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GM862-QUAD / PY Hardware User Guide

1. r 1 SZ E d e D WW d 3 x Pr mar ay Agen paaa g Reproduction forbidden without Telit Communications S p A written authorization All Rights Reserved page 7 of 68 VA e Telit GM862 QUAD PY Hardware User Guide 1vv0300748 Rev 5 20 09 07 3 Interface connectors on GM862 QUAD PY 3 1 Description The Telit GM862 QUAD PY is provided of the following interfaces e GSM antenna connector e Board To Board Interface connector e SIM Card Reader The Telit GM862 QUAD PY board to board connector is a CSTP 50 pin vertical SMD Molex 5299 1 0508 male 3 2 Connectors Position Board to Board Connector GSM Antenna Connector SIM Card Holder e ad Reproduction forbidden without Telit Communications S p A written authorization All Rights Reserved page 8 of 68 e Telit GM862 QUAD PY Hardware User Guide 1vv0300748 Rev 5 20 09 07 3 3 Board to Board Connector Molex 52991 0508 male GM862 Connector LAY OUT 1 80 on 2 20 DEE t he 0 25 ean MIN TYP 12 LAYOUT COMPONENT SIDE Reproduction ep without Telit Communications S p A written authorization All Rights h page 9 of 68 Z e Telit GM862 QUAD PY Hardware User Guide 1vv0300748 Rev 5 20 09 07 3 3 1 Molex 52991 0508 male GM862 Connector PIN OUT Pin
2. The following pictures explain these constraints fixing point flexible cable starting point x WW Os Angle connector fixing example K II EWERS as aN Za a 3 a gt i M a S dh et 8 demm Reproduction forbidden without Telit Communications S p A written authorization All Rights Reserved page 64 of 68 e Telit GM862 QUAD PY Hardware User Guide 1vv0300748 Rev 5 20 09 07 fixing point flexible cable starting point Angle connector fixing example 2 NOTE in the examples the cable is always bent this is not a constrain If the installation does not require it then the cable can be kept straight ensuring that the fixing is without sliding 13 2Precautions e The plug should be inserted in the connector only after the installation of the Telit GM862 QUAD PY in the board This is to prevent accidental breaking of the antenna connection during the transport e The coaxial cable must be fixed at least in one point without sliding possibilities e The plug insertion removal must be done axially with the female connector of the GM862 keeping lateral strains to a minimum e The insertion crimping pull out force must be less than 15N e The Hole s diameter for GM862 shielding reed soldering is 1 5 0 05 mm kag Reproduction forbidden without Telit Communications S p A written authorization All Rights h page 65 of 68 Z e Telit
3. The Base Band Chip of the GM862 QUAD PY Telit Module provides two different audio blocks both in transmit Uplink and in receive Downlink direction e MT lines should be used for handset function e HF lines is suited for hands free function car kit These two blocks can be active only one at a time selectable by AXE hardware line or by AT command The audio characteristics are equivalent in transmit blocks but are different in the receive ones and this should be kept in mind when designing Reproduction forbidden without Telit Communications S p A written authorization All Rights h page 36 of 68 Le e Telit GM862 QUAD PY Hardware User Guide 1vv0300748 Rev 5 20 09 07 audio2 skd EXTERNAL AMPLIFIER Balanced 8 16 8n Fully Differential Power Buffers Differential Line Out Drivers GM862 QUAD H 3 BZ E E gt 5 S Vv gt kg D o ast LU Do g Co bi NG SE a gt S 7em 45dBV Pa 45dBV Pa T af J FE peg pa 7 papa Reproduction forbidden without Telit Communications S p A written authorization All Rights Reserved page 37 of 68 VA e Telit GM862 QUAD PY Hardware User Guide 1vv0300748 Rev 5 20 09 07 8 1 Microphone Paths Characteristic and Requirements TIP being the microphone circuitry the more noise sensitive its design and layout must be done with particular care Both microp
4. o OD N Oa a KB O N a a fa Ka AA Oo a P Od N O 17 18 19 20 21 22 23 24 25 26 27 Signal VBATT GND VBATT GND VBATT A D VBATT CHARGE EAR HFt EAR MT EAR HF EAR MTt MIC HF MIC MTt MIC_HF MIC_MT ON_OFF AXE SIMIO C103 TXD PWRMON SIMVCC RESET SIMRST RESERVED SIMCLK SIMIN GPO2 JDR C106 CTS C125 RING GPI1 GPIO8 1 0 Al AO AO AO AO Al Al Al Al Function Main power supply Ground Main power supply Ground Main power supply A D converter 11 bit Input Impedance gt 100Kohm Main power supply Battery Charger Input Handsfree ear output phase Handset earphone signal output phase Handsfree ear output phase Handset earphone signal output phase Handsfree microphone input phase Handset microphone signal input phase Handsfree microphone input phase Handset microphone signal input phase Input command for switching power ON or OFF toggle command Handsfree switching External SIM signal Data I O Serial data input TXD from DTE Module Status ON indication Signal output for power on off control of external devices External SIM signal Power 3 Reset input External SIM signal Reset Reserved External SIM signal Clock External SIM signal Presence active low General purpose output Open Collector Jammer Detect Report Output for Clear to send signal CTS to DTE Output for Ring indicator signal RI to DTE General p
5. PY Hardware User Guide 1vv0300748 Rev 5 20 09 07 Current characteristics Level Typical Output Current 1MA Input Current TuA 4 3 1 Reset signal Signal Function UO Pin RESET Phone reset 23 connector SO301 RESET is used to reset the GM862 QUAD PY modules Whenever this signal is pulled low the GM862 is reset When the device is reset it stops any operation After the release of the reset GM862 QUAD and GM862 QUAD PY are unconditionally rebooted without doing any detach operation from the network where it is registered This behaviour is not a proper shut down because any GSM device is requested to issue a detach request on turn off For this reason the Reset signal must not be used to normally shutting down the device but only as an emergency exit in the rare case the device remains stuck waiting for some network response The RESET is internally controlled on start up to achieve always a proper power on reset sequence so there s no need to control this pin on start up It may only be used to reset a device already on that is not responding to any command NOTE do not use this signal to power off the GM862 QUAD PY Use the ON OFF signal Pin 17 of SO301 to perform this function or the AT SHDN command Reset Signal Operating levels Signal Min Max RESET Input high 2 0V 2 2V RESET Input low OV 0 2V this signal is internally pulled up so the pin can be left floating if not used If unused this signal may be le
6. All Rights Reserved page 16 of 68 Za Reproduction forbidden without Telit Communications S p A written authorization e Telit GM862 QUAD PY Hardware User Guide 1vv0300748 Rev 5 20 09 07 For example 1 Let s assume you need to drive the ON pin with a totem pole output of a 3 5 V microcontroller uP_OUT1 ON Q2 uP_OQUT1 _D gt BC847BW 50T 323 Fs 3 5 e ove d L Is Power ON OFF inpulse GND 2 Let s assume you need to drive the ON pin directly with an ON OFF button OND Reproduction forbidden without Telit Communications S p A written authorization All Rights Reserved page 17 of 68 VA e Telit GM862 QUAD PY Hardware User Guide 1vv0300748 Rev 5 20 09 07 5 2 Turning OFF the GM862 QUAD PY The turning off of the device can be done in two ways e by software command see GM862 QUAD PY Software User Guide e by hardware shutdown e by hardware unconditional shutdown When the device is shut down by software command or by hardware shutdown it issues to the network a detach request that informs the network that the device will not be reachable any more The hardware unconditional shutdown does not issue this request and shuts down immediately the device 5 2 1 Hardware Shutdown To turn OFF the GM862 QUAD PY the pin ON must be tied low for at least 1 second and then released The same circuitry and timing for the power on shall be used The device shuts
7. DECOUPLING CAPACITORS GAD S a UBO2 a aaa a 4 h 15349121D ER 4 i ENE o y Sa Z 15K Ea if oc B 4 re bi ox 50 C627 R645 ma o AB 1000F 47K E Se TO FROM dei SCH GM862 MIC m i 1 gt ET ABN R PISO GND GND a U602 m ng a T53VB12ID Oe o 15K vi 7 o Sis DU a el ee j 4 Pee eee E EE an cn 150k This circuit has a gain of 10 times 20 dB and is therefore suited for the Mic MT input if you have a microphone with a sensitivity close to the suggested one 45 dBV msPa If your microphone has a different sensitivity or if the buffer is connected to the Mic HF inputs then a gain adjustment shall be done by changing resistors R604 and R606 if the required value is not a standard one you can change R605 e R607 and as a consequence the capacitors C636 and C637 to maintain the bandwidth 150 4000Hz at 3dB Reproduction forbidden without Telit Communications S p A written authorization All Rights Reserved page of 68 Ee e Telit GM862 QUAD PY Hardware User Guide 1vv0300748 Rev 5 20 09 07 The buffer gain is given by the formula R604 R606 Gain R605 R607 The C636 and C637 capacitors are placed in order to cut off the gain at higher frequencies than the transmitted GSM band the cutoff frequency 3dB should be 3500Hz in order to have 1dB at 3kHz The cutoff frequency is given by the formula 1 1 ________ Hz egenen 2a
8. GM862 QUAD PY Hardware User Guide 1vv0300748 Rev 5 20 09 07 14 Conformity Assessment Issues The GM862 QUAD 8 GM862 QUAD PY module is assessed to be conforming to the R amp TTE Directive as stand alone products so If the module is installed in conformance with Telit Communications installation instructions require no further evaluation under Article 3 2 of the R amp TTE Directive and do not require further involvement of a R amp TTE Directive Notified Body for the final product In all other cases or if the manufacturer of the final product is in doubt then the equipment integrating the radio module must be assessed against Article 3 2 of the R amp TTE Directive In all cases assessment of the final product must be made against the Essential requirements of the R amp TTE Directive Articles 3 1 a and b safety and EMC respectively and any relevant Article 3 3 requirements The GM862 QUAD amp GM862 QUAD PY module is conform with the following European Union Directives e R amp TTE Directive 1999 5 EC Radio Equipment amp Telecommunications Terminal Equipments e Low Voltage Directive 73 23 EEC and product safety e Directive 89 336 EEC for conformity for EMC In order to satisfy the essential requisite of the R amp TTE 99 5 EC directive the GM862 QUAD amp GM862 QUAD PY module is compliant with the following standards e GSM Radio Spectrum Standard EN 301 511 and 3GPP 51 010 1 e EMC Electromagnetic Compatibility Stand
9. PY UART rx uart 4 DTR 43 Data Terminal Ready Input to the GM862 QUAD PY that controls the dtr_uart DTE READY condition 5 GND 2 4 Ground Ground 6 DSR 33 Data Set Ready Output from the GM862 QUAD PY that indicates dsr_uart the module is ready 7 RTS 45 Request to Send Input to the GM862 QUAD PY that controls the rts_uart Hardware flow control 8 CTS 29 Clear to Send Output from the GM862 QUAD PY that controls cts_uart the Hardware flow control 9 RI ri_uart 30 Ring Indicator Output from the GM862 QUAD PY that indicates the incoming call condition NOTE According to V 24 RX TX signal names are referred to the application side therefore on the GM862 QUAD PY side these signal are on the opposite direction TXD on the application side will be connected to the receive line here named TXD rx_uart of the GM862 QUAD PY serial port and vice versa for RX p TIP For a minimum implementation only the TXD and RXD lines can be connected the other lines can be left open provided a software flow control is implemented The signals of the TRACE serial port are GM862 Signal a BY Name Usage Number RX TRACE 41 Python Debug Receive line Input line of Python Debug serial Port TX TRACE 35 Python Debug Transmit line Output line of Python Debug serial Port GND 2 4 Ground Ground GG Reproduction forbidden without Telit Communications S p A written authorization All Rights Reserved page 31 of 68 VA e Tel
10. MIC HF or MIC MT depending on the audio path chosen or if possible it should be placed close to the shielded cable connector If the ground return path is well designed then it is possible to eliminate the C3 capacitor provided the buffer is close to the mic input NOTE The cable to the microphone should be shielded NOTE The microphone changes with the value of R2 Usually the microphone sensitivity is characterized with 2kQ biasing resistance so try to keep the value of R2 around 2kQ For mic characteristics refer to the manufacturer e Reproduction forbidden without Telit Communications S p A written authorization All Rights h page 44 of 68 VA e Telit GM862 QUAD PY Hardware User Guide 1vv0300748 Rev 5 20 09 07 8 5 Microphone Buffering As seen previously a microphone shall be connected to the input pins of the GM862 QUAD PY through a buffer amplifier that boosts the signal level to the required value Again the buffered microphone circuitry can be balanced or unbalanced where possible it is always preferable a balanced solution The buffering circuit shall be placed close to the microphone or close to the microphone wire connector 8 5 1 Buffered Balanced Mic A sample circuit can be BALANCED MICROPHONE BUFFER 20dB 34 D i R615 wS 5 i ATK sali Ee
11. Power saving CFUN 0 module registered on the network and can receive voice call or an SMS but it is not possible to send AT AT CFUN 0 or 7 20 3 562 commands module wakes up with an unsolicited code call or AT CFUN 5 SMS or rising RTS line CFUN 5 full functionality with power saving module registered on the network can receive incoming calls and SMS RX mode 1 slot in downlink 52 3 2 slot in downlink 65 2 GSM Receiving data mode 3 slot in downlink 78 6 4 slot in downlink 88 4 GSM TX and RX mode Min power level 78 1 GSM Sending data mode Max power level 200 1 GPRS class 10 TX and RX mode Min power level 123 7 GPRS Sending data mode Max power level 370 8 The GSM system is made in a way that the RF transmission is not continuous else it is packed into bursts at a base frequency of about 216 Hz the relative current peaks can be as high as about 2A Therefore the power supply has to be designed in order to withstand with these current peaks without big voltage drops this means that both the electrical design and the board layout must be designed for this current flow 1 Worst best case depends on network configuration and is not under module control if T a Reproduction forbidden without Telit Communications S p A written authorization All Rights Reserved page 21 of 68 PA e Telit GM862 QUAD PY Hardware User Guide 1vv0300748 Rev 5 20 09 07 If the layout of the PCB is not well designed a strong noise floo
12. a microcontroller with a serial port UART that works at a voltage different from 2 8 3V then a circuitry has to be provided to adapt the different levels of the two set of signals As for the RS232 translation there are a multitude of single chip translators For example a possible translator circuit fora 5V TRANSMITTER RECEIVER can be HO TOTWZZ4FR Tab Gi ep 2 BY ERD TO DEM HAHOWAHE A 2 Bu TO GMaG2 Ha DN AxB_2 BY TOF SZO7AFE BNC TIP This logic IC for the level translator and 2 8V pull ups not the 5V one can be powered directly from PWRMON line of the GM862 QUAD PY Note that the TC7SZ07AE has open drain output therefore the resistor R2 is mandatory paaa g Reproduction forbidden without Telit Communications S p A written authorization All Rights Reserved page 34 of 68 VA e Telit GM862 QUAD PY Hardware User Guide 1vv0300748 Rev 5 20 09 07 NOTE The UART input line TXD rx uart of the GM862 QUAD PY is NOT internally pulled up with a resistor so there may be the need to place an external 47KQ pull up resistor either the DIR dtr uart and RTS rts uart input lines are not pulled up internally so an external pull up resistor of 47KQ may be required A power source of the internal interface voltage corresponding to the 2 8VCMOS high level is available at the PWRMON pin on the connector whose absolute maximum output current is 1mA A maximum of 9 resistors of 47 KO pull up c
13. down after the release of the ON pin TIP To check if the device has powered off the hardware line PWRMON should be monitored When PWRMON goes low the device has powered off _ e Reproduction forbidden without Telit Communications S p A written authorization All Rights Reserved page 18 of 68 Le e Telit GM862 QUAD PY Hardware User Guide 1vv0300748 Rev 5 20 09 07 5 2 2 Hardware Unconditional Restart To unconditionally Shutdown the GM862 QUAD PY the pin RESET must be tied low for at least 200 milliseconds and then released The maximum current that can be drained from the RESET pin is 0 15 mA A simple circuit to do it is si ee Unconditional Restart impulse A AA A 3 9 VV V NOTE don t use any pull up resistor on the RESET line nor any totem pole digital output Using pull up resistor may bring to latch up problems on the GM862 QUAD PY power regulator and improper functioning of the module The line RESET must be connected only in open collector configuration TIP The unconditional hardware Restart should be always implemented on the boards and software should use it as an emergency exit procedure M em lt g Le Reproduction forbidden without Telit Communications S p A written authorization All Rights Reserved page 19 of 68 e Telit GM862 QUAD PY Hardware User Guide 1vv0300748 Rev 5 20 09 07 For example 1 Let s assume you n
14. earphone Reproduction forbidden without Telit Communications S p A written authorization All Rights Reserved page 54 of 68 VA e Telit GM862 QUAD PY Hardware User Guide 1vv0300748 Rev 5 20 09 07 9 6 Car Kit Speakerphone Design For the car kit speaker phone function the power output requirement is usually at least 4W therefore an amplifier is needed to boost the GM862 QUAD PY output The design of the amplifier shall comply with the following guidelines The input to the amplifier MUST be taken from the Ear HE audio path of the GM862 QUAD PY because of its echo canceller parameters suited to a car cabin use The amplifier shall have a gain of 30 40 times 29 32 dB to provide the desired output power of 5 10W with the signal from the GM862 QUAD PY Ear HE audio output lines If the amplifier has a fixed gain then it can be adjusted to the desired value by reducing the input signal with a resistor divider network The amplifier shall have a mute control to be used while not in conversation This results in two benefits eliminating the background noise when not in conversation and saving power The power to the amplifier should be decoupled as much as possible from the GM862 QUAD PY power supply by either keeping separate wires and placing bypass capacitors of adequate value close to the amplifier power input pads The biasing voltage of the amplifier shall be stabilized with a low ESR e g a tantalum capac
15. forbidden without Telit Communications S p A written authorization All Rights Reserved page 13 of 68 VA e Telit GM862 QUAD PY Hardware User Guide 1vv0300748 Rev 5 20 09 07 42 GSM Antemna Installation Guidelines e Install the antenna in a place covered by the GSM signal e The Antenna must be installed to provide a separation distance of at least 20 cm from all persons and must not be co located or operating in conjunction with any other antenna or transmitter e Antenna shall not be installed inside metal cases e Antenna shall be installed also according Antenna manufacturer instructions 4 3 Logic level specifications Where not specifically stated all the interface circuits work at 2 8V CMOS logic levels The following table shows the logic level specifications used in the Telit GM862 QUAD PY interface circuits Absolute Maximum Ratings Not Functional Parameter Min Max Input level on any 0 3V 3 6V digital pin when on Input voltage on 0 3V 3 0 V analog pins when on Voltage on Buffered 0 3V 25V pins Operating Range Interface levels 2 8V CMOS Level Min Max Input high level 2 1V 3 3V Input low level OV 0 5V Output high level 2 2V 3 0V Output low level OV 0 35V For 2 0V signals Operating Range Interface levels 2 0V CMOS Level Min Max Input high level 1 6V 3 3V Input low level OV 0 4V Output high level 1 65V 2 2V Output low level OV 0 35V page 14 of 68 VA Telit GM862 QUAD
16. the upper as inverting and the lower as not inverting configuration we obtain an additional 6dB gain 2 times Remember the not inverting amplifier section gain shall not be less than 1 Like for the balanced buffered microphone the amplifier overall gain can be modify changing the value of resistor R719 R720 and R711 and as a consequence the capacitors C726 and C727 It is advisable to change R708 only if you have difficulty to find a commercial value for R711 in this case change R708 as little as possible The 3dB bandwidth is given by the approximated formula considering C725 gt gt C726 freq l Hz Reproduction forbidden without Telit Communications S p A written authorization All Rights Reserved page of 68 e Telit GM862 QUAD PY Hardware User Guide 1vv0300748 Rev 5 20 09 07 The buffer bandwidth at 3dB shall be 4KHz Note that the biasing of the operational amplifier is given for the inverting amplifier by the series divider R714 R715 The 100nF capacitor C719 is needed to filter the noise that could be coupled to that divider For the not inverting operational amplifier the biasing is given by a different divider R7 15 R717 with the capacitor C720 and through a series resistor R718 of 470KQ TIP example of calculation Let s assume you have a microphone with a sensitivity of 45dBV Pa and you want to use it in 2nd differential microphone path Mic HF
17. 000 R711 2 65 10 F modified in 6 8nF f 4181Hz and 2 7nF f 2 3931Hz because of commercial values Reproduction Paden without Telit Communications S p A written authorization All Rights Reserved page 49 of 68 VA e Telit GM862 QUAD PY Hardware User Guide 1vv0300748 Rev 5 20 09 07 9 OUTPUT LINES Speaker 9 1 Short Description The Telit GM862 QUAD PY provides two audio paths in receive section Only one of the two paths can be active at a time selectable by AXE hardware line or by AT command You must keep in mind the different audio characteristics of the receive blocks when designing gt the Ear MT lines EPN1 and EPP1 are the Differential Line Out Drivers they can drive an external amplifier or directly a 16 Q earpiece at 12dBFS gt the Ear_HF lines EPPA1 2 and EPPA2 are the Fully Differential Power Buffers they can directly drive a 160 speaker in differential balanced or single ended unbalanced operation mode FS acronym of Full Scale It is equal to OdB the maximum Hardware Analog Receive Gain of BaseBand Chip The Ear MT audio path should be used for handset function while the Ear_HF audio path is suited for hands free function car kit Both receiver outputs are B T L type Bridged Tie Load and the OEM circuitry shall be designed bridged to reduce the common mode noise typically generated on the ground plane and to get the maximum power output fr
18. 15 SAFETY RECOMMANDATIONS READ CAREFULLY Be sure the use of this product is allowed in the country and in the environment required The use of this product may be dangerous and has to be avoided in the following areas LI Where it can interfere with other electronic devices in environments such as hospitals airports aircrafts etc Q Where there is risk of explosion such as gasoline stations oil refineries etc It is responsibility of the user to enforce the country regulation and the specific environment regulation Do not disassemble the product any mark of tampering will compromise the warranty validity We recommend following the instructions of the hardware user guides for a correct wiring of the product The product has to be supplied with a stabilized voltage source and the wiring has to be conforming to the security and fire prevention regulations The product has to be handled with care avoiding any contact with the pins because electrostatic discharges may damage the product itself Same cautions have to be taken for the SIM checking carefully the instruction for its use Do not insert or remove the SIM when the product is in power saving mode The system integrator is responsible of the functioning of the final product therefore care has to be taken to the external components of the module as well as of any project or installation issue because the risk of disturbing the GSM network or external devices or having impact o
19. 3 Configurable GPIO CMOS2 8V 1uA 1mA INPUT HIGH HIGH 47K Pull Up 4 7K Pull Up Alternate function 47 GPIO4 I O GPIO04 Configurable GPIO CMOS 2 8V 1uA 1mA INPUT EE Ee Control E Alternate function 48 GPIO5 VO GP1005 Configurable GPIO CMOS2 8V 1uA 1mA INPUT LOW BA 49 GPIO6 VO GPIOO6 Configurable GPIO CMOS2 8V 1uA 1mA INPUT mom HIGH Sa 50 GPIO7 WO GPIO07 Configurable GPIO CMOS2 8V 1uA 1mA INPUT LOW EE 32 GPIO8S VO GPIO08 Configurable GPIO CMOS2 8V 1uA 1mA INPUT LOW 34 GPIO9 VO GPIO09 Configurable GPIO CMOS2 8V 1uA 1mA INPUT LOW 38 GPIO10 I O GPIO10 Configurable GPIO CMOS2 8V 1uA 1mA INPUT LOW 40 GPIO11 Vo GPIO11 Configurable GPIO CMOS2 8V 1uA 1mA INPUT HIGH HIGH 4 7K Pull Up 42 GPIO12 I O GPIO12 Configurable GPIO CMOS2 8V 1uA 1mA INPUT HIGH HIGH 47K Pull Up 44 GPIO13 I O GPIO13 Configurable GPIO CMOS 2 8V 1uA 1mA INPUT LOW Input pins can only be read and report the digital value high or low present on the pin at the read time output pins can only be written or queried and set the value of the pin output an alternate function pin is internally controlled by the GM862 QUAD PY firmware and acts depending on the function implemented 1 Reproduction forbidden without Telit Communications S p A written authorization All Rights A page 56 of 68 e Telit GM862 QUAD PY Hardware User Guide 1vv0300748 Rev 5 20 09 07 Not all GPIO pins support all these three modes e GPIO1 is an INPUT ONLY e GPIO2 is an OUTPUT O
20. 52991 0508 male of your Telit GM862 QUAD PY modules When mounting the Telit GM862 QUAD PY modules on your board take care of soldering the GM862 shielding reeds on a ground plane or signal Molex 53748 0504 female low profile Connector LAY OUT e GZ N DaF TYP wea 900000 00000 00000100 NA ka PCB LAYOUT COMPONENT SIDE paaa Reproduction forbidden without Telit Communications S p A written authorization All Rights Reserved page 63 of 68 VA e Telit GM862 QUAD PY Hardware User Guide 1vv0300748 Rev 5 20 09 07 NOTE be very careful when connecting the Telit GM862 module RF connector The Telit GM862 module RF connector can be damaged if not connected with the proper antenna RF connector The minimum number of insertion cycles is recommended 13 1Antenna Coaxial Cable Fixing The following constraints must be respected in the Telit GM862 QUAD PY modules antenna cable connection e The fixing point of the coaxial cable must not be placed too close to the antenna connector of the GM862 module leaving at least 30mm of flexible cable between the fixed point and the plug end e The fixing point must be at the same height of the GM862 module antenna connector eventually using a wedge between the PCB and the cable if it is directly fixed to the PCB e The flexible cable must never be bent with a radius lower than 25mm RG174 cable e The cable must be a RG174 type or more flexible ones
21. 862 QUAD PY debe ser conforme a los usos para los cuales ha sido dese ado descritos en este manual del usuario FR L int gration du module cellulaire GSM GPRS GM862 QUAD PY dans application de Putilisateur sera faite selon les r gles de conception d crites dans ce manuel HE tt anna Sw r TYAN NI Joona MUNAA NPA NR DU Wann MUDUNNT AWIT DY GM862 QUAD PY The information presented in this document is believed to be accurate and reliable However no responsibility is assumed by Telit Communications S p A for its use nor any infringement of patents or other rights of third parties which may result from its use No license is granted by implication or otherwise under any patent rights of Telit Communications S p A other than for circuitry embodied in Telit products This document is subject to change without notice page 6 of 68 VA e Telit GM862 QUAD PY Hardware User Guide 1vv0300748 Rev 5 20 09 07 2 Dimensions The Telit GM862 QUAD PY module overall dimension are e Length 43 9 mm e Width 43 9 mm e Thickness 6 9 mm e Volume 13 cm The layout is shown in the following figure 43 1 1 pl E oe ee wo 0 7 K 15 35 43 9 L4 7 2 8 0 5 EE pi Pr Zo
22. A NAINA KANA NAN AGA 60 Th ADC EROR NANANA NANANA 61 11 1 ADC e En TEE 61 11 1 1 DESCH PLOW EE 61 11 1 2 Using ADC Converter 61 12 Indication of network service availability cc Gn 62 13 Mounting the GM862 Modules on your Board nannnnnnnnnnnaaa nna 63 13 1 Antenna Coaxial Cable Fixing maamin ANAN AURA 64 13 2 TU EE 65 14 Conformity Assessment DT ATA 66 15 SAFETY RECOMMANDATIONG ccccccssceeecesseeeeeeeeeseeeeeeeeneeeeseueseeeseaeeneeeseeaneeessanans 67 16 Document Change E E 68 E T J Cd iA gaa 3 TA _ ome Dt ee a tap ES Reproduction forbidden without Telit Communications S p A written authorization All Rights Reserved page 3 of 68 Ee e Telit GM862 QUAD PY Hardware User Guide 1vv0300748 Rev 5 20 09 07 This document is relating to the following products GM862 QUAD 3 990 250 659 GM862 QUAD PY 3 990 250 658 H Wi 4 gg Le a Reproduction forbidden without Telit Communications S p A written authorization All Rights Reserved page 4 of 68 VA e Telit GM862 QUAD PY Hardware User Guide 1vv0300748 Rev 5 20 09 07 DISCLAIMER The information contained in this document is the proprietary information of Telit Communications S p A and its affiliates TELIT The contents are confidential and any disclosure to persons other than the officers employees agents or subcontractors of the owner or licensee of this document without the prior wr
23. E BUFFER 110 dB 3VLEXT MIG SINGLE fei 3V EXT MIG SINGLE mee a M3PBB p714 4 sa 88 ATK il GNO DA nang 3 a U 01 T a g8 153v912ID Ebe GM862_MIC DECOUPLING CAPACITORS Ox an vem EIER Ka f BS ng v II TEE cc 5 al i m A 4 1 gt u CH B E R C719 R7156 GE Th ns Sa a WU D oat 1000F 47k m g o MIC PUN ops TOMIC 1 Dd la a r TO l a R 0603 0503 ou E om t m eU mu keg 1 M862 MIC D Dzon o 5 27nF i 7 SZ ENG A GHD GHD r 4 3YL EXT MIG 5INELE S a U701 EI i teg SEER GMB862_MIC 9v_EXT_MIC SINGLE na a a7 J a L EXT MIC oy if O E ye 1 p i i seg R720 i i Kl 10K fi7 2s em o y GMD mo ga S Ea T E 0603 De nG ga 0603 4 a Est tO g nt C725 uoo C720 R715 1000F Ir u H 100nF AFK Z iby r a YAY IBY EE Ei lan 0603 0603 0603 GNG GNC GNOD The above schematic can be used for a single ended buffered unbalanced microphone the required biasing circuitry is not included Note also that the capacitor C3 is not needed The gains of the two amplifiers are given by the formulas R719 R720 R711 Gain inverting buffer R708 Gain not inverting buffer 1 Assigning half of overall gain to each amplifier you will obtain the requested gain because of doubling the microphone signal path in fact by the use of two amplifiers
24. NLY open collector e GPIO3 GPIO8 to GPIO13 support both input or output mode but not Alternate function e GPIO4 supports all three modes and can be input output RF Transmission Control Alternate function e GPIO5 supports all three modes and can be input output RFTXMON output Alternate function e GPIO6 supports all three modes and can be input output ALARM output Alternate function e GPIO7 supports all three modes and can be input output BUZZER output Alternate function All GPIO pins except from GPIO1 and GPIO2 that are buffered with a transistor are 2 8V CMOS signals fig 01 ch1 ON OFF 2sec ch2 GPIO 06 bis ch2 chl GM862 Reproduction forbidden without Telit Communications S p A written authorization All Rights h page 57 of 68 VA e Telit GM862 QUAD PY Hardware User Guide 1vv0300748 Rev 5 20 09 07 10 1 GPIO Logic levels Where not specifically stated all the interface circuits work at 2 8V CMOS logic levels The following table shows the logic level specifications used in the GM862 QUAD PY interface circuits Absolute Maximum Ratings Not Functional Parameter Min Max Input level on any digital 0 3V 3 6V pin when on Input voltage on analog 0 3V 3 0 V pins when on Operating Range Interface levels 2 8V CMOS Level Min Max Input high level 21V 3 3V Input low level OV 0 5V Output high level 2 2V 3 0V Output
25. QUAD PY a 100 F tantalum capacitor is usually suited e Make sure the low ESR capacitor on the power supply output usually a tantalum one is rated at least 10V e A protection diode should be inserted close to the power input in order to save the GM862 QUAD PY from power polarity inversion D D e Reproduction forbidden without Telit Communications S p A written authorization All Rights Reserved page 22 of 68 Le e Telit GM862 QUAD PY Hardware User Guide 1vv0300748 Rev 5 20 09 07 An example of linear regulator with 5V input is 154 input linear regulator 3 5V OUT YAB1 LT1528Ca 5 INPUT ek a o pi D2 293 e203 Ganz i 1 1 1 1 BR ADA Su Zu ky D COR EHD BRAPA d Ea Sii EOS CONT E ie Sho 1 i i I 7 1 F OM l H l Dani 30 I m f 5605 i I l H Ges i l E 1 l 1 Reproduction forbidden without Telit Communications S p A written authorization All Rights A page 23 of 68 VA e Telit GM862 QUAD PY Hardware User Guide 1vv0300748 Rev 5 20 09 07 6 2 1 2 12V input Source Power Supply Design Guidelines e The desired output for the power supply is 3 8V hence due to the big difference between the input source and the desired output a linear regulator is not suited and shall not be used A switching power supply will be preferable because of its better efficiency especially with the 2A peak current load r
26. ROVG CO36 freq TIP example of calculation Let s assume you have a microphone with a sensitivity of 45 dBV m Pa and you want to use it in 1st differential microphone path Mic MT inputs in normal spoken conditions at acoustic pressure of 4 7dBPa As reported at page 33 the electrical level output from the microphone will be MicLevel 45 4 7 49 7 dBvims MicVoltage 210 22310 Vms corresponding to When the talker is screaming we will have a signal of 330 mV mson the Mic MT inputs due to a 20dB higher Mic Level see TIP 1 with a buffer gain G4 G 20 log AmplifierOutput MicVoltage 20 log 330 10 3 33 10 3 20 log 10 20dB The corresponding values for the resistors on the buffer could be if we keep the input resistance 10kQ R604 R606 gain R607 gain R605 10 15 150 kQ The commercial values of 150kQ 8 15kQ are then chosen As a consequence the values of the capacitors C636 and C637 shall be C636 C637 1 21r 4000 R606 265 10 F A commercial value of 270pF gives a cutoff frequency of 3931Hz with an errorless than 1 8 as D d H 3 gt E f KS d 8 Reproduction forbidden without Telit Communications S p A written authorization All Rights Reserved page 46 of 68 VA e Telit GM862 QUAD PY Hardware User Guide 1vv0300748 Rev 5 20 09 07 8 5 2 Buffered Unbalanced Single Ended Microphone SINGLE ENDED MICROPHON
27. S e Jeli wireless solutions GM862 QUAD PY Hardware User Guide GM862 QUAD PY GM862 QUAD HW User Guide 1vv0300748 Rev 5 20 09 07 E i IAN y j Ea ii fy D EATR nl Y4 2 AG E y Zi 3 b Em All H SH Making machines talk VA e Telit GM862 QUAD PY Hardware User Guide 1vv0300748 Rev 5 20 09 07 Contents D e e EE 6 2 DiIM NnSiONS eege ee EES eu 7 3 Interface connectors on GM862 QUAD PY EN 8 3 1 DESCHIPTOM Z ebeegebeeg gege Eden Deeg ANA AR 8 3 2 Connectors POSITION ma AGAR BEAN GAN aaa 8 3 3 Board to Board Connector seeks enegeEe gek ES E geed SSES Ee 9 3 3 1 Molex 52991 0508 male GM862 Connector DIN OUT 10 3 3 2 Antenna eene 12 gt Antenna AA APA AA AA AA 13 4 1 GSM Antenna RequirementSi nana IBANAG nG 13 4 2 GSM Antenna Installation Guidelines SEENEN NENNEN EEN En 14 4 3 Logic level SpeclliCall0NS aaa inneni aeaaea eaaa aaeeea 14 4 3 1 Ee LEE 15 5 Hardware Commands ee 16 5 1 Turning ON the GM662 QUAD PY daa akan BINA AILEEN 16 5 2 Turning OFF the GM862 QUAD PY eeekeeEEEEEEEEEN EENEG 18 5 2 1 Hardware ShutdoWwN EE GANAN MANA Kr adders 18 5 2 2 Hardware Unconditional Restart 19 6 Power Supply saa AGA AA AA AA 21 6 1 Power Supply Requirements 1 20000000000000000EEEEESEEESEESSSESSSSSS20S22002200SsSSSSNNASNASNNNNNA SAAN 21 6 2 General Design RUES aaa ANAN AABANG 22 6 2 1 Electrical Design Guidelines ee an nuna erties GNG NN AKNG eee ee ENNA ANAE e
28. T 2 8V 3V Universal Asynchronous Receive Transmit e microcontroller UART 5V or other voltages different from 2 8V Depending from the type of serial port on the OEM hardware a level translator circuit may be needed to make the system work The only configuration that doesn t need a level translation is the 2 8V UART The TRACE Serial Port is a 3 wire RX TX GND 2 8V UART The MODEM serial port on the GM862 QUAD PY is a 2 8V UART with all the 7 RS232 signals It differs from the PC RS232 in the signal polarity RS232 is reversed and levels The levels for the GM862 QUAD PY UART are the CMOS levels Absolute Maximum Ratings Not Functional Parameter Min Max Input level on any 0 3V 3 6V digital pin when on Input voltage on analog 0 3V 3 0 V pins when on Operating Range Interface levels 2 8V CMOS Level Min Max Input high level Vu 21V 3 3V Input low level Vu OV 0 5V Output high level Voy 2 2V 3 0V Output low level Vo OV 0 35V page 30 of 68 VA e Telit GM862 QUAD PY Hardware User Guide 1vv0300748 Rev 5 20 09 07 The signals of the GM862 QUAD PY MODEM serial port are RS232 GM862 Pin Signal QUAD PY Name Usage Number Pin Number 1 DCD 36 Data Carrier Detect Output from the GM862 QUAD PY that indicates dcd uart the carrier presence 2 RXD 37 Transmit line see Note Output transmit line of GM862 QUAD PY UART tx uart 3 TXD 20 Receive line see Note Input receive of the GM862 QUAD
29. an be connected to the PWRMON pin provided no other devices are connected to it and the pulled up lines are GM862 QUAD PY input lines connected to open collector outputs in order to avoid latch up problems on the GM862 QUAD PY Care must be taken to avoid latch up on the GM862 QUAD PY and the use of this output line to power electronic devices shall be avoided especially for devices that generate spikes and noise such as switching level translators micro controllers failure in any of these condition can severely compromise the GM862 QUAD PY functionality O NOTE The input lines working at 2 8VCMOS can be pulled up with 47KQ resistors that can be connected directly to the PWRMON line provided they are connected as in this example NO OTHER devices than those suggested should be powered with the PWRMON line otherwise the module functionality may be compromised It is important to consider that the added circuit must have consumption lower than 1mA In case of reprogramming of the module has to be considered the use of the RESET line to start correctly the activity The preferable configuration is having an external supply for the buffer ME gh e eg pr kag 6 ay A ii el 1 7 5 e e Reproduction forbidden without Telit Communications S p A written authorization All Rights Reserved page 35 of 68 e Telit GM862 QUAD PY Hardware User Guide 1vv0300748 Rev 5 20 09 07 8 Audio Section Overview
30. and it will be again LOW after hanged up The line rises up 300ms before first TX burst and will became again LOW from 500ms to 1sec after last TX burst 10 5 Using the Alarm Output GPIO6 The GPIO6 pin when configured as Alarm Output is controlled by the GM862 QUAD PY module and will rise when the alarm starts and fall after the issue of a dedicated AT command This output can be used to power up the GM862 QUAD PY controlling microcontroller or application at the alarm time giving you the possibility to program a timely system wake up to achieve some periodic actions and completely turn off either the application and the GM862 QUAD PY during sleep periods dramatically reducing the sleep consumption to few UA In battery powered devices this feature will greatly improve the autonomy of the device CO NOTE During RESET the line is set to HIGH logic level S no NG Reproduction forbidden without Telit Communications S p A written authorization All Rights Reserved page 59 of 68 e Telit GM862 QUAD PY Hardware User Guide 1vv0300748 Rev 5 20 09 07 10 6Using the Buzzer Output GPIO7 The GPIO7 pin when configured as Buzzer Output is controlled by the GM862 QUAD PY module and will drive with appropriate square waves a Buzzer driver This permits to your application to easily implement Buzzer feature with ringing tones played at the call incoming on SMS incoming or simply playing a tone w
31. ards EN 301 489 1 and EN 301 489 7 e LVD Low Voltage Directive Standards EN 60 950 In this document and the Hardware User Guide Software User Guide all the information you may need for developing a product meeting the R amp TTE Directive is included The GM862 QUAD amp GM862 QUAD PY module is conform with the following US Directives Use of RF Spectrum Standards FCC 47 Part 24 GSM 1900 e EMC Electromagnetic Compatibility Standards FCC47 Part 15 To meet the FCC s RF exposure rules and regulations The system antenna s used for this transmitter must be installed to provide a separation distance of at least 20 cm from all the persons and must not be co located or operating in conjunction with any other antenna or transmitter The system antenna s used for this module must not exceed 3 dBi for mobile and fixed or mobile operating configurations Users and installers must be provided with antenna installation instructions and transmitter operating conditions for satisfying RF exposure compliance Manufacturers of mobile fixed or portable devices incorporating this module are advised to clarify any regulatory questions and to have their complete product tested and approved for FCC compliance Kag T at Zi Reproduction forbidden without Telit Communications S p A written authorization All Rights Reserved page 66 of 68 Z e Telit GM862 QUAD PY Hardware User Guide 1vv0300748 Rev 5 20 09 07
32. asing The unbalanced microphone biasing voltage should be obtained from a dedicated voltage regulator in order to eliminate the noise present on the power lines This regulator can be the same for all the audio paths The microphone should be supplied from a capacitor multiply circuit For example a circuit for the unbalanced microphone biasing can be 43 By 3JV MIC MIC Fiasing Regulater Capacity multiply carcuit PSS ae SO SSS eS enie BSD See Sate NN UPS SS SESS SS Se ee te UI LP2dBO4IN5x 3_0 Than wow a 2 ep C1 i R1 3 4 uo 10k ON OFF NCL x v 54 CONTE WER e LORA tak Magog alo HI BCB47Bw Base SOT ges C2 iFs i Her 1 i de CONT Z He EH 5t Electret microphone i GND Bage SSS I SSS wich 2 Hi va T 1 i E l NW shielded 1 To Mic Buffer amplifier 1 p h Cable Mid Mit i m i ca 2 i 220nF b l 1 17h 1 i 10v naga fg EC EER R GND GNI Lette DD BITE DD te Seeks Sec ila Reproduction forbidden without Telit Communications S p A written authorization All Rights Reserved page 43 of 68 Le e Telit GM862 QUAD PY Hardware User Guide 1vv0300748 Rev 5 20 09 07 NOTE In the unbalanced application the capacitor C3 shall be 5 200nF otherwise the frequency response will be cut at low band frequencies down to 300Hz This capacitor can be placed close to the MIC pad
33. crophone Biasing nanana naan nG NONA NAA AN AG AG GN GG EN NANA AKASKSSN NG ENNA AA AKNG Knkk k0 nrasane rennet 42 8 4 2 Unbalanced Microphone Biasing anuna nawa wa inienn KRANKEN ANAKARA ANNEER KAARNA 43 8 5 Microphone Buffering 0 nana 45 8 5 1 Buffered Balanced Mir 45 8 5 2 Buffered Unbalanced Single Ended Microphone ssssssessseesseeesisenesneertntennsttnstnnttnnnnnnrtnneennet 47 9 OUTPUT LINES Speaken aaa NANANA NARARANASAN 50 9 1 Short Descnpon manna AA AA AA REA 50 9 2 Output Lines CharacteristiCs cccissciiieccesievctsvecevscccecccesesestvacetonccstuvestucverescccuuccounceeteecsdenceeters 51 9 3 General Design RUl6s nA NINDA GARA 52 9 3 1 Noise FIREN EE 52 9 4 Handset Earphone Designu nn AG GARENA 53 9 5 Hands Free Earphone Low Power DeSiQl ccccssssseeeeeceeeeeeeeeeeeneeeeeeeeeeeeseeeeeeeeeeeeees 54 9 6 Car Kit Speakerphone Designu jm aaah mamamana 55 10 General Purpose NO y cciscenisniininniaiiwiniwdiniwdniaianwnninaniaanneiniana 56 10 1 GPIO Logic E La KANAN KINAKAIN BINIRA ANA 58 10 2 Using a GPIO pinas INPUT Jaan aa ARIIN AABANG 59 10 3 Using the RF Transmission Control GPIQ4 a 59 10 4 Using the RFTXMON Output GPIQB LL aaa naman aman aaa EERE EARS EERE AE NAS ANAN ANAN ANAN ANAN ANAN NANANA 59 10 5 Using the Alarm Output GPIOG 1 1 nanana mana nA ANNA A AASA AASA NASA A ASA AAS ANAN ANAN ANAN ANAN ANAN NANANA 59 10 6 Using the Buzzer Output GPIO7 1111111111113 A
34. e eeee eee nieeeeenieeeeeeieeeeneaa 22 6 2 1 1 5V input Source Power Supply Design Guidelines snssnnsnnnnseeeennrtnnseestenrrnnseerrrrnnrnnnne ent 22 6 2 1 2 412V input Source Power Supply Design Guidelines nssnnsnensssesnnnrrnnseerttnrrnnsreretrnnnnnnsene 24 6 2 1 3 Battery Source Power Supply Design Guidelines 0 00 0 eee eeeeee ee ette nese tiene ee teeeeeetneeeee 26 6 2 1 4 Battery Charge control Circuitry Design Guidelines uu anwaw nanana awww aananannaananannaanasanana 26 6 2 2 Thermal Design Guidelines a0 naaNNN eeeeaeeeeeeeaeeeseeaaeeeeeeaaeeeeeeaeeeseeiaeeeeeeenaeeeeenaes 28 6 2 3 Power Supply PCB layout Guidelines 20 0 2 eee ener erent etree ee eee aeee ee eeeeee teaser teeeeeeeeeeeee 29 T Serial POMS EE 30 CT Level translation Serie EST ERKENNEN EE aaea Ea NANA AA NAA aaun EEan haa 32 7 2 SV UART level translation isis nb NAN KASE 34 8 Audio Section Overview REENEN 36 D D e Reproduction forbidden without Telit Communications S p A written authorization All Rights Reserved page 2 of 68 Z e Telit GM862 QUAD PY Hardware User Guide 1vv0300748 Rev 5 20 09 07 8 1 Microphone Paths Characteristic and Requirements 11111 1 0 220000 m ssssu a 38 8 2 General Design Rules anas KAANAK UA ANING resend 41 8 3 Other Considerations aasa socssoencestecesdeasuercseascessdsaausnesehseesusevshedesesdeesnerso 41 8 4 Microphone emt naaa AA AA 42 8 4 1 Balanced Mi
35. edicated power supply This is because in this way the level translator IC outputs on the module side i e GM862 QUAD PY inputs will work at 3 8V interface levels stressing the module inputs at its maximum input voltage This can be acceptable for evaluation purposes but not on production devices E 11 755 aN G 38 SA Em i f e Reproduction forbidden without Telit Communications S p A written authorization All Rights Reserved page 32 of 68 Le e Telit GM862 QUAD PY Hardware User Guide 1vv0300748 Rev 5 20 09 07 An example of level translation circuitry of this kind is ca U201 MAX3237EAL SSOP 28 oO im gt RX_RS232 1 4C 23 mD D CO DCD RS232 1 4C pa 2D Daanan RING RS232 1 4C 19 DR DOH tant O DSR RS232 1 4C 17 CTs O In CTS_RS232 1 4C 16 2 RTS C CIRTS gea 1 4D 3 2D DIR CIDTR RS232 1 4D mD To X mor CI TX_RS232 1 4C 2D 3v0 RS232 LEVEL TRSANSLATOR the RS232 serial port lines are usually connected to a DB9 connector with the following layout OCD_AS23 EB Wa ka DSR RS232 7 TX_ AS232 C a II ATS_RS232 lt _ _AS232 DD lu CTS AS232 D DTR AS232 TIN RI RS232 7 GND Reproduction forbidden without Telit Communications S p A written authorization All Rights h page 33 of 68 e Telit GM862 QUAD PY Hardware User Guide 1vv0300748 Rev 5 20 09 07 7 2 5V UART level translation If the OEM application uses
36. eed to drive the RESET pin with a totem pole output of a 3 5 V microcontroller UP OUT2 gt RESET Qe BCH47BW 501 323 1F5 TR The hardware unconditional restart must not be used during normal operation of the device since it does not detach the device from the network It shall be kept as an emergency exit procedure to be done in the rare case that the device gets stacked waiting for some network or SIM responses If device does not respond to a command in the timeout window retry issuing the command and if still no response is received a hardware reset shall be issued e Tag Reproduction forbidden without Telit Communications S p A written authorization All Rights Reserved page 20 of 68 VA e Telit GM862 QUAD PY Hardware User Guide 1vv0300748 Rev 5 20 09 07 6 Power Supply The power supply circuitry and board layout are the most important part in the full product design and they strongly reflect on the product overall performances hence read carefully the requirements and the guidelines that will follow for a proper design 6 1 Power Supply Requirements Nominal Supply Voltage 3 8 V Max Supply Voltage 4 2 V Supply voltage range 3 4 V 4 2 V Mode Average mA Mode description IDLE mode Stand by mode no call in progress AT CFUN 1 23 9 Normal mode full functionality of the module AT CFUN 4 22 Disabled TX and RX module is not registered on the network
37. en the battery is discharged and its voltage drops below a certain threshold GM862 QUAD PY internal charger does it As you can see the charging process is not a trivial task to be done moreover all these operations should start only if battery temperature is inside a charging range usually 5 C 45 C The GM862 QUAD PY measures the temperature of its internal component in order to satisfy this last requirement it s not exactly the same as the battery temperature but in common application the two temperature should not differ too much and the charging temperature range should be guaranteed NOTE In this particular application the battery charger input current must be limited to less than 1A Using a current limited wall adapter as the power source can do this For your convenience in the EVK there s also a current unlimited input where the input source is not limited in current and the drawn current is limited to about 0 5A by a MOSFET in the EVK The external battery charger is suggested in applications where the total consumption is higher than the current provided by the GM862 QUAD PY module D NOTE For all the threshold voltages inside the GM862 QUAD PY all threshold are fixed in order to maximize Li lon battery performances and do not need to be changed NOTE In this application the battery charger input current must be limited to less than 400mA This can be done by using a current limited wall adapter a
38. epresented by the GM862 QUAD PY e When using a switching regulator a 500Khz switching frequency regulator is preferable because of its smaller inductor size and its faster transient response This allows the regulator to respond quickly to the current peaks absorption e In any case the frequency and Switching design selection is related to the application to be developed due to the fact the switching frequency could also generate EMC interferences e For car PB battery the input voltage can rise up to 15 8V and this should be kept in mind when choosing components all components in the power supply must withstand this voltage e A Bypass low ESR capacitor of adequate capacity must be provided in order to cut the current absorption peaks a 100 F tantalum capacitor is usually suited e Make sure the low ESR capacitor on the power supply output usually a tantalum one is rated at least 10V e For Car applications a spike protection diode should be inserted close to the power input in order to clean the supply from spikes e A protection diode should be inserted close to the power input in order to save the GM862 QUAD PY from power polarity inversion This can be the same diode as for spike protection Reproduction forbidden without Telit Communications S p A written authorization All Rights Reserved page 24 of 68 e Telit GM862 QUAD PY Hardware User Guide 1vv0300748 Rev 5 20 09 07 An example of switching regulator wi
39. er Saving function is enabled it is possible to consider from the thermal point of view that the device absorbs current significantly only during calls If we assume that the device stays into transmission for short periods of time let s say few minutes and then remains for a quite long time in idle let s say one hour then the power supply has always the time to cool down between the calls and the heat sink could be smaller than the calculated one for 500mA maximum current or even could be the simple chip package no heat sink Moreover in the average network conditions the device is requested to transmit at a lower power level than the maximum and hence the current consumption will be less than the 500mA being usually around 150mA For these reasons the thermal design is rarely a concern and the simple ground plane where the power supply chip is placed can be enough to ensure a good thermal condition and avoid overheating page 28 of 68 Z e Telit GM862 QUAD PY Hardware User Guide 1vv0300748 Rev 5 20 09 07 6 2 3 Power Supply PCB layout Guidelines As seen on the electrical design guidelines the power supply shall have a low ESR capacitor on the output to cut the current peaks and a protection diode on the input to protect the supply from spikes and polarity inversion The placement of these components is crucial for the correct working of the circuitry A misplaced component can be useless or can even decrease the power sup
40. fer to SW User Guide or to GM862 QUAD PY AT Commands User Guide for the full description of this function PB Reproduction forbidden without Telit Communications S p A written authorization All Rights Reserved page 61 of 68 VA e Telit GM862 QUAD PY Hardware User Guide 1vv0300748 Rev 5 20 09 07 12 Indication of network service availability The STAT LED pin status shows information on the network service availability and Call status The pin is an Open Collector output where it is possible to directly connect a LED to show information on the network service availability and Call status Therefore the status indicated in the following table is reversed with respect to the pin status LED status permanently off fast blinking period 1s Ton 0 5s slow blinking period 3s Ton 0 3s permanently on LU 5 el Device Status device off Net search Not registered turning off Registered full service a call is active ba e e Reproduction forbidden without Telit Communications S p A written authorization All Rights Reserved page 62 of 68 VA e Telit GM862 QUAD PY Hardware User Guide 1vv0300748 Rev 5 20 09 07 13 Mounting the GM862 Modules on your Board In order to electrically connect your board to the Telit GM862 QUAD PY modules use a CSTP 2x25 pin vertical SMD SCH SCH Molex 53748 0504 female low profile as a counterpart to the CSTP 50 pin vertical SMD Molex
41. ft unconnected If used then it must always be connected with an open collector transistor to permit to the internal circuitry the power on reset and under voltage lockout functions a zZ Reproduction forbidden without Telit Communications S p A written authorization All Rights Reserved page 15 of 68 p e Telit GM862 QUAD PY Hardware User Guide 1vv0300748 Rev 5 20 09 07 5 Hardware Commands 5 1 Turning ON the GM862 QUAD PY To turn on the GM862 QUAD PY the pin ON must be tied low for at least 1 second and then released The maximum current that can be drained from the ON pin is 0 1 mA A simple circuit to do it is ON RI S Bd If ik N N A Ql ale IT VV v N J Power ON impulse so ay KINO R2 Kag OP NOTE don t use any pull up resistor on the ON line it is internally pulled up Using pull up resistor may bring to latch up problems on the GM862 QUAD PY power regulator and improper power on off of the module The line ON must be connected only in open collector configuration NOTE The GM862 QUAD PY turns fully on also by supplying power to the Charge pad Module provided with a battery on the VBATT pads TIP To check if the device has powered on the hardware line PWRMON should be monitored After 900ms the line raised up the device could be considered powered on PWRMON line rises up also when supplying power to the Charge pad
42. g this current limit depends on the required time for the complete charge and from the battery pack capacity During this phase the voltage across the battery terminals still raises but at a lower rate Once the battery voltage reaches its maximum voltage then the process goes into its third state Final charging The voltage measure to change the process status into final charge is very important It must be ensured that the maximum battery voltage is never exceeded otherwise the battery may be damaged and even explode Moreover for the constant voltage final chargers the constant voltage phase final charge must not start before the battery voltage has reached its maximum value otherwise the battery capacity will be highly reduced The final charge can be of two different types constant voltage or pulsed The constant voltage charge proceeds with a fixed voltage regulator very accurately set to the maximum battery voltage and hence the current will decrease while the battery is becoming charged page 26 of 68 Z e Telit GM862 QUAD PY Hardware User Guide 1vv0300748 Rev 5 20 09 07 When the charging current falls below a certain fraction of the fast charge current value then the battery is considered fully charged the final charge stops and eventually starts the maintenance The pulsed charge process has no voltage regulation instead the charge continues with pulses Usually the pulse charge works in the following manner the cha
43. general purpose UO pin 47 Kohm CMOS 2 8V 47 GPIO4 UO Configurable general purpose I O pin TX Disable Control 4 7 Kohm CMOS 2 8V 48 en UO Configurable general purpose UO pin Transmitter ON Monitor CMOS 2 8V 49 E ue ee general purpose UO pin CMOS 2 8v 50 GE ue Configurable general purpose UO pin CMOS 2 8v BUZZER 1 For the exclusive use of the Technical Support Service 2 An earphone with a 150 ohm impedance can be directly connected to EAR and EAR 3 On this pin a maximum of 10nF bypass capacitor is allowed Note If not used almost all pins should be left disconnected The only exceptions are the following pins pin signal 1 3 5 7 VBATT 2 4 8 GND 17 ON OFF 20 TXD 23 RESET 37 RXD 45 RTS RTS should be connected to the GND on the module side if flow control is not used page 11 of 68 Telit GM862 QUAD PY Hardware User Guide 1vv0300748 Rev 5 20 09 07 3 3 2 Antenna Connector The Telit GM862 QUAD PY includes one 50 Ohm MMCX coaxial female RF connector On the user application side the following connector must be used 45 15 a Telegartner MMCX angle plug crimp Order n J01340A0121 NOTE be very careful when connecting the Telit GM862 QUAD PY RF connector The RF connector can be damaged if not connected with the proper antenna RF connector The minimum number of insertion cycles are recommended Reproduction ep without Telit Communications S p A written authorizati
44. gh pass cut can be obtained with the formula Gain KO R2 1 req RP Hz fred apa sca MA And an example of internal Ear amplifier could be INTERNAL EAR AMPLIFIER 12dB a 1 1 m i 1 oye zg Zce o mb 1 1 mi v oh ag 1 4 pa 5 i 1 i 1 i 42 7 bt 1 1 2 a LM4662M z Zom ba Pr 1 ER geet TO SPEAKER 5 bop IW ape ae SS i Iran nu 1 ai L EAR K d BJ SHUTDONN bo g i a ee Tua FROMGM862 QUAD PY EAR lt T vor BYPASS Dsp a Chai cBa2 7 lawn Ing l ag 25 eae aonn iaon 1 vey Kai 1 CROZ HM Hu 1 1C0nF Opus 0803 i Tea C801 He oe we PLAS i GEN 12156061 03F i Cep 4 i 7 1 Pan Hara i 2 MUTE CONTROLLED f 1 1 DI ba d Zi Se il ALWAYS ON i ppm Je i END i 1 GHD GAO 1 AMPLI POWER CONTROL i 1 ieee oe Skee ee SSeS BEB at eee ea BOGE Bea eed Some amplifier require a low impedance load at high frequency in order to avoid auto oscillation this can be made with a capacitor 100nF in series with a resistor 150 When designing your application remember to provide an adequate bypass capacitor to the amplifier and place it close to the power input pin of the IC keeping the traces as short as possible 9 5 Hands Free Earphone Low Power Design The same design considerations made for the handset are valid for the hands free
45. hanges Release First ISSUE 0 Added chapter 11 Conformity assessment Issues Modified 3 3 1 4 1 4 2 4 3 6 1 6 2 14 Modified 3 3 1 removed chapter 13 camera Updated DISCLAIMER Added note on charger CFUN4 and ON_OFF Added Power consumptions table Added new table for GPIO status in Reset and Power on added RFTXMON timing Switching description modified in 12V input Source Power Supply Design Guidelines Added Alternate Function for GPIO4 modified absolute maximum ratings added GPIO2 Alternate function description added safety recommendations removed schematic for stat led updated schematics for On off and Reset Updated 8 1 Microphone Paths Characteristic and Requirements paragraph TE
46. hen needed by your application A sample interface scheme is included below to give you an idea of how to interface a Buzzer to the GPIO7 Mu R112 47E SG 1 a Q102 8 SS BZ101 Sou E AK 30T 23 SMUS 1 227 Ge SMBT29074 3 3 e CH Ll D 2 Sia D101 new a MCL4148 JC d iez 2 Em BCR 141W A oa SOT 323 4 a Ws dub db 1 NOTE To correctly drive a buzzer a driver must be provided its characteristics depend on the Buzzer and for them refer to your buzzer vendor Reproduction forbidden without Telit Communications S p A written authorization All Rights Reserved page 60 of 68 11 11 1 11 1 VA e Telit GM862 QUAD PY Hardware User Guide 1vv0300748 Rev 5 20 09 07 ADC section 11 1ADC converter 1 Description The GM862 QUAD PY module provides a Analog to Digital Converter The input line named ADC IN1 is available on pin 6 of the B2B connector of the module and on pin 19 of PL103 on EVK2 Board The on board A D is 11 bit converter It is able to read a voltage level in the range of 0 2 volts applied on the ADC pin input store and convert it into 11 bit word Min Max Units Input Voltage range 0 2 Volt AD conversion 11 bits Resolution lt 1 mV 2 Using ADC Converter An AT command is available to use the ADC function The command is ATHADC 1 2 The read value is expressed in mV Re
47. hese conditions the attenuation can be considered as a thumb rule around 20dB For the earphone we shall distinguish two different types the earphones having the microphone sustained close to the mouth and the ones having the microphone on the earpiece cable The same considerations for the additional voice attenuation due to the distance from the microphone and the noise pick up can be made for the earphone having the microphone on the earpiece cable while the other kind of earphone shall be threaten as an handset TIP how to compensate the losses in car cabin hands free condition The voice signal that in the normal spoken conditions produces on the microphone membrane an acoustic pressure of 4 7dBPa at 1kHZz will have a further attenuation of 20dB due the 50cm distance Therefore a microphone having the suggested nominal sensitivity of 45ABV Pa will produce a lower electrical that means MeVollage 510 0 33 10 Setting the microphone gain at 10dB 3 times the signal in the nominal conditions on the Mic HF inputs s of GM862 QUAD PY Telit Module will be Mic HE Level 0 33 10 3 3 1 10 _ re dg 7 Reproduction forbidden without Telit Communications S p A written authorization All Rights Reserved page 40 of 68 VA e Telit GM862 QUAD PY Hardware User Guide 1vv0300748 Rev 5 20 09 07 Hence in these conditions the signal level on the Mic_HF input pads of
48. hone paths are balanced and the OEM circuitry should be balanced designed to reduce the common mode noise typically generated on the ground plane However also an unbalanced circuitry can be used for particular OEM application needs TIP due to the difference in the echo canceller type the Mic MT audio path is suited for p Handset applications while the Mic_HF audio path is suited for hands free function car kit The Earphone applications should be made using the Mic_HF audio path but DISABLING the echo canceller by software AT command If the echo canceller is left active with the Earphone then some echo might be introduced by the echo cancel algorithm Mic MT 1 differential microphone path e line coupling AC e line type balanced e coupling capacitor 2 100nF e differential input resistance 50kQ e max differential input voltage 1 03Vpp 365MV ms MicG 0 e microphone nominal sensitivity 45 ABV ms Pa e analog gain suggested 20dB e echo canceller type handset Mic HF 2 differential microphone path e line coupling AC e line type balanced e coupling capacitor 2 100nF e differential input resistance 50kQ e max differential input voltage 1 03V 365MV ms MicG 0 e microphone nominal sensitivity 45 ON el H e analog gain suggested 10dB e echo canceller type car kit hands free Reproduction forbidden without Telit Communications S p A written authorizatio
49. icrophone amplifier TIP example of external microphone amplifier calculation Let s suppose to use the 1 differential microphone path In this case the maximum differential input voltage to Mic MI lines is 365MVims 1 03Vpp corresponding to 8 76dBV Now we can calculate the maximum voltage gain of an external microphone amplifier G4 MicLevel 20dB G 8 76dBV D D e Reproduction forbidden without Telit Communications S p A written authorization All Rights Reserved page 39 of 68 VA Telit GM862 QUAD PY Hardware User Guide 1vv0300748 Rev 5 20 09 07 49 7 20 G 8 76 40 9 20 G G 20 94dB you can set Ga 20dB to use standard resistor values TIP environment consideration For hands free car kit microphone you must take into account the voice attenuation due to the distance between the microphone itself and the talker when designing the external microphone amplifier Not only you must consider that the microphone will pick up also ambient noise to overcome this problem it is preferable to set the gain of the microphone 70dB lower with respect to the calculated value for a nominal sensitivity The corresponding reduction in signal level will be compensated by an increased voice volume of the talker which will speak louder because of the ambient noise For a car cabin usually the distance between the microphone itself and the talker is 40 50cm in t
50. inputs in normal spoken conditions at acoustic pressure of 4 7dBPa As reported at page XX the electrical level output from the microphone will be MicLevel 45 4 7 49 7 ABV ms but we have to consider 20dB loss due to the higher distance from the mouth of the talker 50cm MicLevel 49 7 20 69 7 dBV ms cee aera at MicVoltage 10 427 20 0 33 107 In order to have a signal of 1 MVms at the Mic HE inputs as suggested at TIP environment consideration the buffer must have a gain Gu Mic HF MicVoltage 1 10 3 0 33 10 or 10 dB a Keeping in mind that balancing the line will double the signal to calculate the resistor values assign half of required gain Ga to each amplifier section And therefore Gs 1 5times or 3 52dB Choosing as 10kQ as the input resistance the corresponding values for the resistors on the buffer will be R711 Gs R708 1 510 15 kQ R719 Gg 1 R720 1 5 1 10 5 kQ The commercial values of 15kQ and 5 6kQ be accepted S por er af i NT i f L d h k s5 Te Ss Reproduction forbidden without Telit Communications S p A written authorization All Rights Reserved page 48 of 68 e Telit GM862 QUAD PY Hardware User Guide 1vv0300748 Rev 5 20 09 07 As a consequence of the assigned values of the resistors the nominal values of C726 and C727 are C726 1 217 4000 R719 7 10 10 F C727 1 217 4
51. it GM862 QUAD PY Hardware User Guide 1vv0300748 Rev 5 20 09 07 7 1 Level translation In order to interface the Telit GM862 QUAD PY with a PC com port or a RS232 EIA TIA 232 application a level translator is required This level translator must e invert the electrical signal in both directions e change the level from 0 3V to 15 15V Actually the RS232 UART 16450 16550 16650 amp 16750 chipsets accept signals with lower levels on the RS232 side EIA TIA 562 allowing for a lower voltage multiplying ratio on the level translator Note that the negative signal voltage must be less than OV and hence some sort of level translation is always required The simplest way to translate the levels and invert the signal is by using a single chip level translator There are a multitude of them differing in the number of driver and receiver and in the levels be sure to get a true RS232 level translator not a RS485 or other standards By convention the driver is the level translator from the 0 3V UART level to the RS232 level while the receiver is the translator from RS232 level to 0 3V UART In order to translate the whole set of control lines of the UART you will need e 5 driver e 3 receiver NOTE The digital input lines working at 2 8VCMOS have an absolute maximum input voltage of 3 75V therefore the D level translator IC shall not be powered by the 3 8V supply of the module Instead it shall be powered from a 2 8V 3 0V d
52. it for the balanced microphone biasing can be t3V MIC V E MIC Biasing Regulator Capacity multiply circuit sc i Ean AE Se ele ro REN Ey Ci ee eee ud LPR9ODAIMSX 3 0Q iN von H l S 1 j Z Jon C1 Ri i 3 F our EH ON OFF nel ty l av pa 0402 F Laga ea VER 1 i KI 3 gt i i 2 BC847Bw Dede DINAANAN xD a 1 501 322 1 Ce Fs i Alay 4 i Kees 1 i Av Re dk 1 i wi pa Electret micropnane NU 0402 POSS pea AES 1 ii MICH R 3 1 i i i b l 7 b To MIC Buffer amplifier MK 1 1 SE i H 1 1 MIS R3 i ik 1 1 aaa ARR aQ aaa i ex 1 o402 NOTE In the balanced application the resistors R2 and R3 must have the same value to keep GJ Si BS Za Reproduction forbidden without Telit Communications S p A written authorization All Rights Reserved page 42 of 68 VA e Telit GM862 QUAD PY Hardware User Guide 1vv0300748 Rev 5 20 09 07 NOTE The cable to the microphone should not be shielded instead a twisted pair cable shall be used NOTE The microphone sensitivity changes with the value of R2 and R3 Usually the microphones are characterized with 2kQ biasing resistance so try to keep the sum of R2 and R3 around 2kQ Refer to your microphone manufacturer for the mic characteristics 8 4 2 Unbalanced Microphone Bi
53. ited and for some particular applications may not be enough For these reasons when the power output of the GM862 QUAD PY is not enough or if the speaker characteristics are different from the suggested then it is preferable to use an amplifier to increase the power and current output capabilities Again the output from the GM862 QUAD PY is bridged and both lines should be used where possible as inputs to the power amplifier This ensures a higher common mode rejection ratio reducing the GSM current busts noise on the speaker output In this case the EAR MT lines from the GM862 QUAD PY should be AC coupled with a ceramic capacitor of 100nF or bigger It is always desirable to have a mute control on the amplifier in order to turn it off while the device is not sending signal to the output in this manner the amplifier background noise which may be audible during idle conditions is cut off A principle schematic may be cal is m T n4 47k NCC A 4 au Ou S i Cap Wii 1 EAR QUT CT UT na a t 3 Wi H Cap MT Ui S 1 2 FE ES ycc a END C1 HE iu 147k fit eer eNO GND RS Ee LS d Reproduction forbidden without Telit Communications S p A written authorization All Rights Reserved page 53 of 68 VA e Telit GM862 QUAD PY Hardware User Guide 1vv0300748 Rev 5 20 09 07 The resulting gain and hi
54. itor of adequate value NOTE The GM862 QUAD PY audio path connected to the car kit hands free amplifier MUST be Ear_HF one otherwise the echo cancellation will not be done due to the difference in the echo canceller characteristics of the GM862 QUAD PY internal audio path from the external audio path Example of car kit amplifier schematic HIGH POWER EXT EAR AMPLIFIER 6w Se ceoeSOe EEDIT EDDIE SS eee eee ADA eee ADD RSC EE eee eee og ou i ver a 7 5 EE i i D zl ad JEAP HF4 l aut F C913 Agge TO SPEAKER 1 a al 3 OHM i wl Ten Fa ER a ng ms in C bai Cl OSILS JEAP H CAR RODE Capo c90 Big 300nF 1000uF 6 MUTE SSES Su D av T PLOGd 3 1 wi L cain C308 a 7 D ai e el HUTE CONTAOLLED E Ha a ALWAYS ON GONT E pos Ga ND ew AMPLI POWER CONTAOL page 55 of 68 Le e Telit GM862 QUAD PY Hardware User Guide 1vv0300748 Rev 5 20 09 07 10 General Purpose O The general purpose I O pins can be configured to act in three different ways e input e output e alternate function internally controlled The following GPIO are available on the GM862 QUAD PY GPI1 GPI01 Configurable GPIO CMOS 2 8V 1uA 1mA INPUT Open Collector 28 GPO2 O GPO02 Configurable GPIO CMOS 2 8V 1uA 1mA OUTPUT LOW Alternate function JDR 46 GPI03 VO GPIO0
55. itten consent of Telit is strictly prohibited Telit makes every effort to ensure the quality of the information it makes available Notwithstanding the foregoing Telit does not make any warranty as to the information contained herein and does not accept any liability for any injury loss or damage of any kind incurred by use of or reliance upon the information Telit disclaims any and all responsibility for the application of the devices characterized in this document and notes that the application of the device must comply with the safety standards of the applicable country and where applicable with the relevant wiring rules Telit reserves the right to make modifications additions and deletions to this document due to typographical errors inaccurate information or improvements to programs and or equipment at any time and without notice Such changes will nevertheless be incorporated into new editions of this document All rights reserved 2006 2007 Telit Communications S p A 2 Ko Reproduction forbidden without Telit Communications S p A written authorization All Rights Reserved page 5 of 68 VA e Telit GM862 QUAD PY Hardware User Guide 1vv0300748 Rev 5 20 09 07 1 Overview The aim of this document is the description of some hardware solutions useful for developing a product with the Telit GM862 QUAD PY module In this document all the basic functions of a mobile phone will be taken into accoun
56. low level OV 0 35V For 2 0V signals Operating Range Interface levels 2 0V CMOS Level Min Max Input high level 1 6V 3 3V Input low level OV 0 4V Output high level 1 65V 2 2V Output low level OV 0 35V HH a s E 7 EN j d Po BA paaa g Reproduction forbidden without Telit Communications S p A written authorization All Rights Reserved page 58 of 68 VA e Telit GM862 QUAD PY Hardware User Guide 1vv0300748 Rev 5 20 09 07 10 2 Using a GPIO pin as INPUT The GPIO pins when used as inputs can be connected to a digital output of another device and report its status provided this device has interface levels compatible with the 2 8V CMOS levels of the GPIO If the digital output of the device to be connected with the GPIO input pin has interface levels different from the 2 8V CMOS then it can be connected to GPIO1 or can be buffered with an open collector transistor provided a 47KQ pull up to 2 8V 10 3 Using the RF Transmission Control GPIO4 The GPIO4 pin when configured as RF Transmission Control Input permits to disable the Transmitter when the GPIO is set to Low by the application 10 4 Using the RFTXMON Output GPIO5 The GPIO5 pin when configured as RFTXMON Output is controlled by the GM862 QUAD PY module and will rise when the transmitter is active and fall after the transmitter activity is completed For example if a call is started the line will be HIGH during all the conversation
57. n All Rights Reserved page 38 of 68 VA Telit GM862 QUAD PY Hardware User Guide 1vv0300748 Rev 5 20 09 07 WARNING AC means that the signals from microphone has to be connected to input lines of the module by a CAPACITOR which value must be 2 100nF Not respecting this constraint the input stage will be damaged TIP definition of the nominal sensitivity of the microphone lines The nominal sensitivity of the microphone lines indicates the voltage level on the GM862 QUAD PY pins present during normal spoken conditions For a handset the normal spoken conditions take place when the talker mouth is 7cm far from the microphone under these conditions the voice will produce an acoustic pressure of 4 7dBPa 1kHz on the microphone membrane TIP electrical equivalent signal and operating voice levels At normal spoken conditions a microphone having the suggested nominal sensitivity of 45dBV m3 Pa will produce the electrical equivalent signal that means During a call this level varies according to the volume of the talker voice usually the following rough thumb rule for the dynamic range may be used 1 the talker is screaming This is the strongest voice level condition the signal increases by 20dB 2 the talker is whispering This is the lowest voice level condition the voice level decreases by 50dB These changes must be considered for designing the external m
58. n the security Should there be any doubt please refer to the technical documentation and the regulations in force Every module has to be equipped with a proper antenna with specific characteristics The antenna has to be installed with care in order to avoid any interference with other electronic devices and has to guarantee a minimum distance from the body 20 cm In case of this requirement cannot be satisfied the system integrator has to assess the final product against the SAR regulation The European Community provides some Directives for the electronic equipments introduced on the market All the relevant information s are available on the European Community website http europa eu int comm enterprise rtte dir99 5 htm The text of the Directive 99 05 regarding telecommunication equipments is available while the applicable Directives Low Voltage and EMC are available at http europa eu int comm enterprise electr equipment index en bim kaa Ags d Reproduction forbidden without Telit Communications S p A written authorization All Rights Reserved page 67 of 68 VA e Telit GM862 QUAD PY Hardware User Guide 1vv0300748 Rev 5 20 09 07 16 Document Change Log Revision ISSUE 0 ISSUE 1 ISSUE 2 ISSUE 3 ISSUE 4 ISSUE 5 Reproduction forbidden without Telit Communications S p A written authorization All Rights Reserved page 68 of 68 Date 16 10 06 24 10 06 19 12 06 08 01 07 02 07 07 20 09 07 C
59. om the device however also a single ended circuitry can be designed for particular OEM application needs Ze Reproduction forbidden without Telit Communications S p A written authorization All Rights Reserved page 50 of 68 e Telit GM862 QUAD PY Hardware User Guide 1vv0300748 Rev 5 20 09 07 9 2 Output Lines Characteristics Ear MT Differential Line out Drivers Path line coupling line type output load resistance internal output resistance signal bandwidth max differential output voltage differential output voltage SW volume level step number of SW volume steps Ear HF Power Buffers path line coupling line type output load resistance internal output resistance signal bandwidth max differential output voltage max single ended output voltage SW volume level step number of SW volume steps SZ S dE Ai e ER a 4 f d At DC bridged 2140 4 Q typical 150 4000 Hz 3 dB 1310 MVims typ open circuit 328mVrms 16 Q 12dBFS 2 dB 10 DC bridged 2140 40 gt 1 70 150 4000 Hz 3 dB 1310 MVims typ open circuit 656 MVims typ open circuit 2dB 10 emm paaa g Reproduction forbidden without Telit Communications S p A written authorization All Rights Reserved page 51 of 68 VA e Telit GM862 QUAD PY Hardware User Guide 1vv0300748 Rev 5 20 09 07 9 3 General Design Rules There are several configu
60. on All Rights h page 12 of 68 VA e Telit GM862 QUAD PY Hardware User Guide 1vv0300748 Rev 5 20 09 07 4 Antenna 4 1 GSM Antenna Requirements The antenna for a Telit GM862 QUAD PY device shall fulfill the following requirements Frequency range Depending by frequency band s provided by the network operator the customer shall use the most suitable antenna for that those band s Bandwidth 80 MHz in EGSM 900 70 MHz if GSM 850 170 MHz in DCS 140 MHz PCS band Gain Gain lt 3dBi Impedance 50 ohm Input power 5 2 W peak power VSWR absolute lt 10 1 max VSWR lt 2 1 recommended Furthermore if the device is developed for the US market and or Canada market it shall comply to the FCC and or IC approval requirements This device is to be used only for mobile and fixed application The antenna s used for this transmitter must be installed to provide a separation distance of at least 20 cm from all persons and must not be co located or operating in conjunction with any other antenna or transmitter End Users must be provided with transmitter operation conditions for satisfying RF exposure compliance OEM integrators must ensure that the end user has no manual instructions to remove or install the GM862 QUAD PY module Antennas used for this OEM module must not exceed 3dBi gain for mobile and fixed operating configurations MH 5 55 N Par EA ZB Dada NG ANI ED E ee ma D e R e Reproduction
61. on as previous point Try to keep this trace as short as possible e The PCB traces connecting the Switching output to the inductor and the switching diode must be kept as short as possible by placing the inductor and the diode very close to the power switching IC only for switching power supply This is done in order to reduce the radiated field noise at the switching frequency 100 500 kHz usually e The use of a good common ground plane is suggested e The placement of the power supply on the board should be done in such a way to guarantee that the high current return paths in the ground plane are not overlapped to any noise sensitive circuitry as the microphone amplifier buffer or earphone amplifier e The power supply input cables should be kept separate from noise sensitive lines such as microphone earphone cables Kag T at Zi Reproduction forbidden without Telit Communications S p A written authorization All Rights Reserved page 29 of 68 VA e Telit GM862 QUAD PY Hardware User Guide 1vv0300748 Rev 5 20 09 07 7 Serial Ports The serial port on the Telit GM862 QUAD PY is the core of the interface between the module and OEM hardware 2 serial ports are available on the module e MODEM SERIAL PORT e TRACE Usable only on GM862 QUAD PY for Python Debug Several configurations can be designed for the serial port on the OEM hardware but the most common are e RS232 PC com port e microcontroller UAR
62. ply performances e The Bypass low ESR capacitor must be placed close to the Telit GM862 QUAD PY power input pins or in the case the power supply is a switching type it can be placed close to the inductor to cut the ripple provided the PCB trace from the capacitor to the GM862 QUAD PY is wide enough to ensure a dropless connection even during the 2A current peaks e The protection diode must be placed close to the input connector where the power source is drained e The PCB traces from the input connector to the power regulator IC must be wide enough to ensure no voltage drops occur when the 2A current peaks are absorbed Note that this is not made in order to save power loss but especially to avoid the voltage drops on the power line at the current peaks frequency of 216 Hz that will reflect on all the components connected to that supply introducing the noise floor at the burst base frequency For this reason while a voltage drop of 300 400 mV may be acceptable from the power loss point of view the same voltage drop may not be acceptable from the noise point of view If your application doesn t have audio interface but only uses the data feature of the Telit GM862 QUAD PY then this noise is not so disturbing and power supply layout design can be more forgiving e The PCB traces to the GM862 QUAD PY and the Bypass capacitor must be wide enough to ensure no voltage drops occur when the 2A current peaks are absorbed This is for the same reas
63. r is generated on the ground and the supply this will reflect on all the audio paths producing an audible annoying noise at 216 Hz if the voltage drop during the peak current absorption is too much then the device may even shutdown as a consequence of the supply voltage drop TIP The electrical design for the Power supply should be made ensuring it will be capable of a peak current output of at least 2 A 6 2 General Design Rules The principal guidelines for the Power Supply Design embrace three different design steps e the electrical design e the thermal design e the PCB layout 6 2 1 Electrical Design Guidelines The electrical design of the power supply depends strongly from the power source where this power is drained We will distinguish them into three categories e 5V input typically PC internal regulator output e 12V input typically automotive e Battery 6 2 1 1 5V input Source Power Supply Design Guidelines e The desired output for the power supply is 3 8V hence there s not a big difference between the input source and the desired output and a linear regulator can be used A switching power supply will not be suited because of the low drop out requirements e When using a linear regulator a proper heat sink shall be provided in order to dissipate the power generated e A Bypass low ESR capacitor of adequate capacity must be provided in order to cut the current absorption peaks close to the GM862
64. rallel to noisy traces especially the power line e The cable to the speaker shall be a twisted pair with both the lines floating for the bridged output type shielded with the shield to ground for the single ended output type 9 3 1 Noise Filtering The I O of the PCB should have a noise filter close to the connector to filter the high frequency GSM noise The filter can be a IT formed by 2 capacitor and a inductance with the one capacitor of 39pF 0603 case and the other capacitor of 1nF 0603 the inductance shall have a value of 39 H D Reproduction forbidden without Telit Communications S p A written authorization All Rights Reserved page 52 of 68 VA e Telit GM862 QUAD PY Hardware User Guide 1vv0300748 Rev 5 20 09 07 9 4 Handset Earphone Design As seen previously a 16Q earpiece can be directly connected to the output pads EAR_MT and EAR MIT of the GM862 QUAD PY This solution is often the more cost effective reducing the components count to a minimum There are several limitations to the use of this solution speakers direct connect imposes the speaker characteristics to be almost exactly the suggested ones otherwise the power output may be reduced if speaker impedance is bigger than 16Q or the GM862 QUAD PY ear port may be damaged if speaker impedance is less than 150 The other limitation of the speaker direct connection is the power output capability of the GM862 QUAD PY which is lim
65. rations for the audio output path but the various design requirements can be grouped into three different categories e handset earphone low power typically a handset e hands free earphone low power typically a earphone e car kit speakerphone high power typically a speaker The three groups have different power requirements usually the first two applications need only few mW of power which can be directly drained from the GM862 QUAD PY pads provided a suited speaker is used This direct connect design is the cheaper and simpler solution and will be suited for the most of the earphone design requirements There s no need to decouple the output ear lines if a suited earpiece is connected For the last group the speakerphone a power amplifier is required to raise the output power up to 5 10W required in a car cabin application All the designs shall comply with the following guidelines e Where possible use a bridged earphone circuitry to achieve the maximum power output from the device e Keep the earphone traces on the PCB and wires as short as possible e f your application requires a single ended earpiece and you want a direct connection then leave one of the two output lines open and use only the other referred to ground Remember that in this case the power output is 4 times lower than the bridged circuit and may not be enough to ensure a good voice volume e Make sure that the earphone traces in the PCB don t cross or run pa
66. rge is stopped for some time let s say few hundreds of ms then the battery voltage will be measured and when it drops below its maximum value a fixed time length charging pulse is issued As the battery approaches its full charge the off time will become longer hence the duty cycle of the pulses will decrease The battery is considered fully charged when the pulse duty cycle is less than a threshold value typically 10 the pulse charge stops and eventually the maintenance starts The last phase is not properly a charging phase since the battery at this point is fully charged and the process may stop after the final charge The maintenance charge provides an additional charging process to compensate for the charge leak typical of a Li lon battery It is done by issuing pulses with a fixed time length again few hundreds of ms and a duty cycle around 5 or less This last phase is not implemented in the GM862 QUAD PY internal charging algorithm so that the battery once charged is left discharging down to a certain threshold so that it is cycled from full charge to slight discharge even if the battery charger is always inserted This guarantees that anyway the remaining charge in the battery is a good percentage and that the battery is not damaged by keeping it always fully charged Li lon rechargeable battery usually deteriorates when kept fully charged Last but not least in some applications it is highly desired that the charging process restarts wh
67. s the power source NOTE When starting the charger from Module powered off the startup will be in CFUN4 to activate the normal mode a command AT CFUN 1 has to be provided This is also possible using the POWER ON There is also the possibility to activate the normal mode using the ON_OFF signal In this case when HW powering off the module with the same line ON_OFF and having the charger still connected the module will go back to CFUN4 Reproduction forbidden without Telit Communications S p A written authorization All Rights Reserved page of 68 VA e Telit GM862 QUAD PY Hardware User Guide 1vv0300748 Rev 5 20 09 07 6 2 2 Thermal Design Guidelines The thermal design for the power supply heat sink should be done with the following specifications e Average current consumption during transmission PWR level max 500mA e Average current consumption during transmission PWR level min 100mA e Average current during Power Saving CFUN 5 4mA e Average current during idle Power Saving disabled 24mA NOTE The average consumption during transmissions depends on the power level at which the device is requested to transmit by the network The average current consumption hence varies significantly TIP The thermal design for the Power supply should be made keeping a average consumption at the max transmitting level during calls of 500mA Considering the very low current during idle especially if Pow
68. t for each one of them a proper hardware solution will be suggested and eventually the wrong solutions and common errors to be avoided will be evidenced Obviously this document cannot embrace the whole hardware solutions and products that may be designed The wrong solutions to be avoided shall be considered as mandatory while the suggested hardware configurations shall not be considered mandatory instead the information given shall be used as a guide and a starting point for properly developing your product with the Telit GM862 QUAD PY module For further hardware details that may not be explained in this document refer to the Telit GM862 QUAD PY Product Description document where all the hardware information is reported NOTICE EN The integration of the GSM GPRS GM862 QUAD PY cellular module within user application shall be done according to the design rules described in this manual IT L integrazione del modulo cellulare GSM GPRS GM862 QUAD PY all interno dell applicazione dell utente dovra rispettare le indicazioni progettuali descritte in questo manuale DE Die integration des GM862 QUAD PY GSM GPRS Mobilfunk Moduls in ein Ger t mu gem der in diesem Dokument beschriebenen Kunstruktionsregeln erfolgen SL Integracija GSM GPRS GM862 QUAD PY modula v uporabni ki aplikaciji bo morala upo tevati projektna navodila opisana v tem piro niku SP La utilizaci n del modulo GSM GPRS GM
69. th 12V input is in the below schematic it is split in 2 parts To SWITCHING VIN OTP 12V INPUT RT201 MF RI10 D202 P6SMB30A 77 77 FIT pa a a a D D H H F T202 F ae U203 50D L5973D RCR I10D 130 Mj vm pi srry pi pi SE 8 Les ari In ek I S 2 R210 C235 C236 C226 C227 10 0K 1000uF luF luF iour ExR XR 1 16V 16V Sov 50V 0603 10x16 0805 1210 CONT D D aD aD GD R212 4 7K Pe 0603 sov 4 7K 0603 Po 0603 SWITCHING REGULATOR Reproduction forbidden without Telit Communications S p A written authorization All Rights Reserved page 25 of 68 Z e Telit GM862 QUAD PY Hardware User Guide 1vv0300748 Rev 5 20 09 07 6 2 1 3 Battery Source Power Supply Design Guidelines e The desired nominal output for the power supply is 3 8V and the maximum voltage allowed is 4 2V hence a single 3 7V Li lon cell battery type is suited for supplying the power to the Telit GM862 QUAD PY module The three cells Ni Cd or Ni MH 3 6 V Nom battery types or 4V PB types MUST NOT BE USED since their maximum voltage can rise over the absolute maximum voltage for the GM862 QUAD PY and damage it NOTE DON T USE any Ni Cd Ni MH and Pb battery types Their use can lead to overvoltage on the GM862 QUAD PY and damage it USE ONLY Rechargeable Li lon battery types e A Bypass low ESR capacitor of adequate capacity must be provided in order to cut the c
70. the GM862 QUAD PY is 10 dB 3 times lower than the nominal as suggested 8 2 General Design Rules There are several configurations for the audio paths but the most effective difference is between balanced and unbalanced microphone configuration It is highly recommended to keep the whole microphone path balanced even if this means having 2 wires connecting the microphone instead of one needed plus ground in the unbalanced case The balanced circuitry is more suited because of its good common mode noise rejection reducing the 216 Hz burst noise produced during the GSM transmissions e Where possible use balanced microphone circuitry e Keep the microphone traces on the PCB and wires as short as possible e f your application requires an unbalanced microphone then keep the lines on the PCB balanced and unbalance the path close to the microphone wire connector if possible e For the microphone biasing voltage use a dedicated voltage regulator and a capacitor multiply circuit e Make sure that the microphone traces in the PCB don t cross or run parallel to noisy traces especially the power line e f possible put all around to the microphone lines a ground trace connected to the ground plane by several vias This is done in order to simulate a shielded trace on the PCB e The biasing circuit and eventually the buffer can be designed in the same manner for the internal and external microphones 8 3 Other Considerations If yo
71. ur application is a hands free car kit scenario but you need to put microphone and speaker inside the same box e Try to have the maximum possible distance between them at least 7cm e since the microphone type is very important if you use an omni directional one and this is the typical application please seal it on the rear side no back cavity in order not to collect unwanted signals e try to make divergent the main axes of the two devices D Reproduction forbidden without Telit Communications S p A written authorization All Rights Reserved page 41 of 68 VA e Telit GM862 QUAD PY Hardware User Guide 1vv0300748 Rev 5 20 09 07 8 4 Microphone Biasing The electret microphones usually need a biasing voltage to work properly Refer to your microphone provider for the characteristics required CO NOTE The microphones have a hot wire were the positive biasing must be connected Usually it is indicated by a symbol or a red point If the polarity of the bias is reversed then the microphone will not work properly For this reason be sure to respect the mic biasing polarity 8 4 1 Balanced Microphone Biasing The balanced microphone bias voltage should be obtained from a dedicated voltage regulator in order to eliminate the noise present on the power lines This regulator can be the same for all the audio paths The microphone should be supplied from a capacitor multiply circuit For example a circu
72. urpose input Configurable general purpose UO pin Internal Pull up Type Power Power Power Power Power Max 2V input Power Power Audio Audio Audio Audio Audio Audio Audio Audio Pull Up to VBATT 100KQ CMOS 2 8V 47KQ 1 8V 3V ONLY CMOS 2 8V 1KQ CMOS 2 8V 1 8V 3V ONLY 1 8V 3V ONLY 1 8V 3V ONLY 47KQ CMOS 2 8V Open Collector CMOS 2 8V CMOS 2 8V transistor base CMOS 2 8V page 10 of 68 VA e Telit GM862 QUAD PY Hardware User Guide 1vv0300748 Rev 5 20 09 07 Internal Pin Signal I O Function Pull up Type 33 C107 DSR O Output for Data set ready signal DSR to DTE CMOS 2 8V 34 GPIO9 I O Configurable general purpose UO pin CMOS 2 8V 35 TX_TRACE O RESERVED on GM862 QUAD Python Debug on GM862 QUAD PY TX data CMOS 2 8V 36 C109 DCD O Output for Data carrier detect signal DCD to DTE CMOS 2 8V 37 C104 RXD O Serial data output to DTE CMOS 2 8V 38 GPIO10 I O Configurable general purpose UO CMOS 2 8V 39 STAT_LED O Status indicator led Open Collector 40 GPIO11 UO Configurable general purpose UO pin 4 7 Kohm CMOS 2 8V 41 RX TRACE RESERVED on GM862 QUAD Python Debug on GM862 QUAD PY RX data CMOS 2 8V 42 GPI012 I O Configurable general purpose UO pin 47 Kohm CMOS 2 8V 43 C108 DTR Input for Data terminal ready signal DTR from DTE CMOS 2 8V 44 GPI013 UO Configurable general purpose UO pin CMOS 2 8V 45 C105 RTS Input for Request to send signal RTS from DTE CMOS 2 8V 46 GPIO3 UO Configurable
73. urrent absorption peaks a 100 F tantalum capacitor is usually suited e Make sure the low ESR capacitor usually a tantalum one is rated at least 10V e A protection diode should be inserted close to the power input in order to save the GM862 QUAD PY from power polarity inversion Otherwise the battery connector should be done in a way to avoid polarity inversions when connecting the battery e The battery capacity must be at least 500mAh in order to withstand the current peaks of 2A the suggested capacity is from 500mAh to 1000mAh 6 2 1 4 Battery Charge control Circuitry Design Guidelines The charging process for Li lon Batteries can be divided into 4 phases Qualification and trickle charging e Fast charge 1 constant current e Final charge constant voltage or pulsed charging e Maintenance charge The qualification process consists in a battery voltage measure indicating roughly its charge status If the battery is deeply discharged that means its voltage is lower than the trickle charging threshold then the charge must start slowly possibly with a current limited pre charging process where the current is kept very low with respect to the fast charge value the trickle charging During the trickle charging the voltage across the battery terminals rises when it reaches the fast charge threshold level the charging process goes into fast charge phase During the fast charge phase the process proceeds with a current limited chargin

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