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SIM908_Hardware Design_V2.00

1. 41 TABLE 20 ABSOLUTE MAXIMUM 5 NA 44 TABLE 21 RECOMMENDED OPERATING 5 2 2221 44 TABLE 22 DIGITAL INTERFACE CHARACTERISTICS lee 44 TABLE 23 SIM CARD INTERFACE CHARACTEKERISTIQZA 45 TABLE 24 VDD EXT CHARACTERISTICS 4 45 TABLE 25 VDD CHARACTERUS f 8 amp N 8 45 26 VRTC CHARACIBRISTICS i aun 45 TABLE 27 GSM CURRENT CONS QWPTIJON 46 TABLE 28 THE ESD CHARACTERISTICS TEMPERATURE 25 C HUMIDITY 45 47 TABLE 29 SIM908 GSM 900 AND GSM 850 CONDUCTED RF OUTPUT POWER 47 TABLE 30 SIM908 DCS 1800 AND PCS 1900 CONDUCTED RF OUTPUT POWER 48 TABLE 31 SIM9Q8 CONDUCTED RF RECEIVE SENSITIVITY 49 TABLE 32 SIMQOXQPERATING FR
2. 33 4 8 2 Design Considerations for SIM Card Holder essere erneuten senes nene eas 34 4 9 LCD Depay uo CMM CM MEE 36 AIO e Ree 36 I pO SS SSS 37 REB OL EE 37 dd 4 ERR ee nme sss 38 4 14 General Purpose Input Output CbPIO 39 Eege 39 A 39 ZI Ee ee 40 GPS Application E an RUE 41 5 1 CGE Oe e E ch m 41 5 2 GPS Poweron down A 42 5 2 1 Power on GPS en glne Mg e dE 42 522 Powerdown GPS EE WE 42 5 3 GPS VANT OUT GPS VANT IN lu 42 5 4 GPS Antenna ee reo Doc ushana es 42 5 4 1 GPS Antenna 2 2 2222 222 2 42 5 4 3 GPS Antenna Choice Consideration 2 2 43 6 Electrical Reliability and Radio Characteristics 44 6 1 Absolute Maximum Ratngs E 44 6 2 Recommended Operating Condrttons ee 44 6 3 Digital Interlace Characteristics u u uuu o Ne H 44 6 4 SIM Card Intertaee Characteristic
3. A company of SIM Tech SIM908 Hardware Design V2 00 Smart Machine Smart Decision Document Title SIM908 Hardware Design Version 2 00 2012 05 07 Document Control ID SIM908 Hardware Design V2 00 General Notes SIMCom offers this information as a service to its customers to support application and engineering efforts that use the products designed by SIMCom The information provided is based upon requirements specifically provided to SIMCom by the customers SIMCom has not undertaken any independent search for additional relevant information including any information that may be in the customer s possession Furthermore system validation of this product designed by SIMCom within a larger electronic system remains the responsibility of the customer or the customer s system integrator All specifications supplied herein are subject to change Copyright This document contains proprietary technical information which 15 the property of SIMCom Limited copying of this document and giving it to others and the using or communication of the contents thereof are forbidden without express authority Offenders are liable to the payment of damages rights reserved in the event of grant of a patent or the registration of a utility model or design specification supplied herein are subject to change without notice at any time Copyright Shanghai SIMCom Wireless Solutions Ltd 2012 SIM908 Hardware Design V
4. WS rore Smart Machine Smart Decision 33 Package Dimensions BOTTOM VIEW TOP VIEW Figure 3 Dimensions of SIM908 Unit mm lt 30 00 _ 25 2 9 00 2 20 e en gt em gt e _ vo ux a gt gt gt gt Figure 4 Recommended PCB footprint outline Unit mm SIM908_Hardware Design_V2 00 16 2012 05 07 m 22 Com Smart Machine Smart Decision 3 4 Mechanical Dimensions of the RF Connector The RF connector in the module side is an ultra small surface mount coaxial connectors Part Number U FL R SMT vended by HRS It has high performance with wide frequency range surface mountable and reflows solder able Following figure are the related parameters Certainly user can visit http www hirose connectors com for more information To get good RF performance in user s design SIMCom suggests user to use the matching RF adapter cable which is also supplied by HRS Part Number U FL LP CV 040 the following figure is the dimensions of UEL series RF adapter cable User can contact SIMCom for more information z H a an un 0 6 H et Figure 5 U FL R SMT Unit mm E iim P N 20278 18 7 2035
5. 23 454 Minimum Functionality eieiei A R egene reegen dereen 23 4 3 2 Sleep Mode 1 22 44444 23 433 Wake Up SIM908 from Sleep Mode 1 AT CSCLK 1 23 Sleep Mode 010 E 24 4 3 5 Wake Up SIM908 from Sleep Mode 2 AT CSCLK 2 24 4 4 Charging ntef g e le 24 441 Bou Rack Ne EE 25 AAD Battery Pack anaana aaa aaa a aaa AASA Saa SA Aasaa 25 Timplemented Charon uuu uuu u a E 25 4 4 4 Operating Modes during Charong 26 AAD Mar R E e e E EEEE 27 4 5 ee 24 4 6 LI 29 461 Function of Serial Port and Debug Port 29 462 Software Upgrade and 22 0 NANENANE NENNEN ENANAR aAa 30 4 7 EE EE 3l AJA Speaker interlace aetema 21 4 7 2 Microphone Interfaces Configuration 32 473 Earphone Interface 32 4 4 Audio Electronic Characteristics EE 32 4 8 SINDC Re 33 SIM908 Hardware Design_V2 00 3 2012 05 07 ee ee 5 Smart Machine Smart Decision ASA SEM Card le e
6. 102 ee Eh Figure 39 GSM antenna matching circuit SIM908_Hardware Design_V2 00 40 2012 05 07 eo 060 09 of SIM Tech Smart Machine Smart Decision In this figure the components R101 R102 C101 and C102 is used for antenna matching the components value only can be got after the antenna tuning Usually matching components value is provided by antenna vendor the default value of R101 and R102 are 00 and reserve the place of C101 and C102 without soldering The RF test connector in figure 39 is used for conducted RF performance test and should be placed as close as possible to the modules RF ANT pad The traces in bold type should be treated as 500 impedance controlled line in PCB layout For details about radio frequency trace layout please refer to document 9 5 GPS Application Interface SIM908 provide a high performance L1 GPS solution for cellular handset applications The solution offers best in class acquisition and tracking sensitivity Time To First Fix TTFF and accuracy The GPS engine supports both fully autonomous operations for use in handheld consumer navigation devices and other standalone navigation systems The GPS NMEA information 15 output by DEBUG port The default baud rate 15 115200bps The GPS engine is controlled by GSM engine so when it is necessary to run GPS GSM engine must powered on and not in SLEEP mode
7. the GPS function is controlled by AT command via serial port The GPS function AT commands are listed in the following table Table 19 AT Commands for GPS function Command Description AT CGPSPWR GPS power control AT CGPSRST GPS mode reset hot warm cold AT CGPSSTATUS Get current GPS status AT CGPSOUT GPS NMEA data output control AT CGPSINF Get current GPS location info AT CGPSIPR Set GPS NMEA output uart bps For details of these AT command please refer to document 1 51 GPS Operating Modes GPS has two operating modes which can be controlled by AT command Active mode GPS is active as a GPS receiver The GPS engine will automatically acquire and track GPS satellites Power down mode The GPS engine will be set into this mode by sending AT command AT CGPSPWR 0 In this mode the internal power supply for GPS will be shutdown and the current consumption 15 very low The last position current time and ephemeris data will be stored in the GSM host memory SIM908 Hardware Design V2 00 41 2012 05 07 060 060 eec A company of SIM Tech 5 2 GPS Power on down Scenarios Smart Machine Smart Decision 5 2 11 Power on GPS engine User can power GPS engine by sending AT command AT CGPSPWR 1 5 2 2 Power down GPS engine User can power down GPS engine by sending AT command AT CGPSPWR 0 53 GPS VANT OUT and GPS VANT IN GPS VANT OUT is a 2 8V output for active external antenna
8. IN TXD VBAT PWRKEY GND C Figure 23 Connection for software upgrading and debugging The serial port and the debug port support the CMOS level If user connects the module to the computer the level shifter should be added between the DCE and DTE For details about software upgrading please refer to document 4 SIM908 Hardware Design V2 00 30 2012 05 07 4 7 Audio Interfaces Qeeee 502222 Smart Machine Smart Decision SIM908 provides two analog inputs MICIP IN and MIC2P 2N which could be used for electret microphone The module also provides two analog outputs SPK1P 1N and SPK2P 2N The output can directly drive 32Q receiver AT command AT CMIC is used to adjust input gain level of microphone AT command AT SIDET is used to set the side tone level In addition AT command AT CLVL is used to adjust the output gain level For more details please refer to document 1 and document 5 In order to improve audio performance the following reference circuits are recommended The audio signals have to be layout according to differential signal layout rules as shown in following figures If user needs to use an amplifier circuit for audio National Semiconductor Company s LM4890 is recommended 4 7 1 Speaker Interface Configuration be placed to speaker as close as possible The lines in bold type should be accorded to
9. 5 8 Smart Machine Smart Decision PWRKEY Power H m on down logic ESD ANTI MODULE Figure 12 Powered on down module using button The power on scenarios is illustrated as following figure P Tpulldown gt 18 Tdelay gt 2 25 x lt gt 2 4V PWRKEY N Virs0 4V Input x x x x gt STATUS Output x Serial Port Undefined X Active Figure 13 Timing of power on module When power on procedure is completed SIM908 will send following URC to indicate that the module is ready to operate at fixed baud rate RDY This does not appear when autobauding function 15 active Note User can use AT command AT IPR x to set a fixed baud rate and save the configuration to non volatile flash memory After the configuration is saved as fixed baud rate the Code RDY should be received from the serial port every time when SIM908 is powered on For details please refer to the chapter AT IPR in document 1 4 2 1 2 Turn on the SIM908 using the VCHG Signal The SIM908 will be automatically turned on when a charger is connected to the switched off SIM908 of which VBAT pin voltage is greater than 3 2V SIM908 will go into the Charge only Mode In this mode the module does not register to the network and has only a few AT commands available When module is powered on using the VCHG signal SIM908 sends out
10. R TEMP Thermistor Figure 16 SIM908 with battery charger and pack connection SIM908_Hardware Design_V2 00 24 2012 05 07 ee ee Smart Machine Smart Decision Battery temperature measurement is a customization function which is supported by the software in the module In above figure the 15 a NTC thermistor and it is recommended to use MURATA NCP15XH103F03RC Its impedance is 10Kohm at 25 Refer to the above figure for the reference circuit 4 4 Battery Pack Characteristics SIM908 has optimized the charging algorithm for the Li Ion battery that meets the characteristics listed below The maximum charging voltage of the Li Ion battery pack 15 4 2V and the recommended capacity is 1100mAh The Battery packs with more than 1100 mAh capacity will take more time for charging The battery pack should have a protection circuit to avoid overcharging deep discharging and over current and the circuit should be insensitive to pulsed current The internal resistance of the battery pack including protection circuit should be as low as possible Its recommended value does not exceed 150mQ The battery pack must be protected from reverse pole connection On the SIM908 the build in circuit of the power management chipset monitorsthe supply voltage constantly Once the Under voltage is detected the SIM908 will be powered down
11. 2 PWM1 ADC VDD EXT GND VRTC GND 2012 05 07 ee of SIM Tech 3 2 Pin Description Smart Machine Smart Decision Table 5 Pin description VBAT 62 63 I Power supply 3 2V 4 8 It is recommended 10 VRTC 42 Power supply for connect with a battery or a capacitor e g 4 7uF VDD EXT 44 O 2 8V output power supply If it is unused keep open GPS VANT OUT 75 O 2 8V output for GPS active antenna If it is unused keep open GPS VANT IN 76 I GPS active antenna power supply If it is unused keep open E2 510111 40 41 43 57 58 GND Ground 60 61 64 65 77 78 80 VCHG I Charger input TEMP 73 I Battery temperature sensor PWRKEY should be pulled low at PWRKEY 3 I least 1 second and then released to Pulled up internally power on down the module MICIP I Differential audio input MICIN 24 SPKIP 22 Differential audio output SPKIN Pu If these pins are unused MIC2P 27 I Differential audio input MIC2N 28 SPK2N 25 Differential audio output SPK2P STATUS 52 Power on status If these pins are unused NETLIGHT 51 O Network status keep open DISP CLK 6 DISP DATA LO r If these pins are unused Display interface DISP D C 8 keep open DISP CS 9 O SIM908_Hardware Design_V2 00 14 2012 05 07 en Smart Machine Smart Decision Machine Smart Decision I2C SDA 56 O serial bus da
12. The other interfaces q RIC Radio Power Power management unit Frequency supply T Digital Interface GPS SIM UART p gt Analog base Digital base A Analog Interface 7 _ 5 gt Audio lt gt e LCD SPI ADC T T GPS UART FLASH Figure 1 SIM906 functional diagram SIM908 Hardware Design V2 00 12 2012 05 07 3 Qeeee 666 A Package Information 31 Pin out Diagram GND GND PW RKEY NC GND DISP CLK DISP DATA DISP D C DISP CS GND NC NC NC GND GPS DBG TXD GPS DBG RXD SIM DATA SIM RST SIM CLK SIM VDD GPS ANT GND GND GPS VANT IN GPS VANT OUT VCHG TEMP BAT 80 GND 79 78 76 75 ESI 69 RXD CTS Q SIM908 VIEW EH 1 _ 6 8 19 10 14 119 20 MIC2P 27 29 30 31 34 36 z O e N r JE t Z Z E EIOOO fo x S SS x x x 008468 GP GP GP GP GP GP Figure 2 SIM908 pin out diagram Top view SIM908 Hardware Design_V2 00 13 Smart Machine Smart Decision GND GSM ANT GND GND 2 I2C SCL NC NC STATUS NETLIGHT PWMS
13. 2 Walt for at least 800mS after STATUS pin changed to low level 3 Power on the module Power down Tdelay gt 800mS Restart gt a gt gt lt PWRKEY N N STATUS x N Figure 15 Timing of restart SIM908 SIM908 Hardware Design_V2 00 22 2012 05 07 ee ee ee A company of SIM Tech 43 Power Saving Mode Smart Machine Smart Decision SIM908 have two sleep modes sleep mode 1 is enabled by hardware pin DTR sleep mode 2 is only enabled by serial port regardless of the DTR In sleep mode the current of module is very low The AT command AT CFUN lt fun gt can be used to set SIM908 into minimum functionality When SIM908 is in sleep mode and minimum functionality the current of module is lowest Note Customer must shut off the power supply of GPS and then the AT commands about the power saving mode can be executed correctly and the current consumption will be lower 4 3 1 Minimum Functionality Mode There are three functionality modes which could be set by the AT command A T CFUN lt fun gt The command provides the choice of the functionality levels lt fun gt 0 1 4 AT CFUN 0 minimum functionality AT CFUN I full functionality default AT CFUN 4 flight mode disable RF function Minimum functionality mode minimizes the current consumption to the lowest level If SIM908 is set to minimum functionality by AT CFUN O the RF function and SIM card function will
14. Smart Machine Smart Decision The table below summarizes the various operating modes of SIM908 Table 4 Overview of operating modes Mode Function Module will automatically go into sleep mode if the conditions of sleep mode are enabling and there is no on air and no hardware interrupt such as GSM GPRS GPIO interrupt or data on serial port SLEEP In this case the current consumption of module will reduce to the minimal level In sleep mode the module can still receive paging message and SMS GSM Software is active Module registered to the GSM network and the module IDLE is ready to communicate Normal Connection between two subscribers 15 in progress In this case power operation TALE consumption depends on network settings such as DTX off on FR EFR HR hopping sequences antenna CURE Module is ready for GPRS data transfer but no data is currently sent or received In this case power consumption depends on network settings and STANDBY GPRS configuration There is GPRS data transfer PPP or TCP or UDP in progress In this case GPRS power consumption is related with network settings e g power control DATA level uplink downlink data rates and GPRS configuration e g used Power down multi slot settings Normal power down by sending the AT command AT CPOWD 1 or using PWRKEY The power management unit shuts down the power supply for the baseband part of the module and only the power supply for the RTC
15. if the active external antenna worksvat 2 8V voltage supply domain user can connect the GPS VANT OUT and GPS VANT IN directly If the antenna s power is not 2 8V a proper voltage should be provided to the pin GPS VANT IN depending on the active antenna and the pin GPS VANT OUT should be kept open For passive antennas both the pin GPS VANT OUT and the pin GPS VANT IN should be kept open 54 GPS Antenna Interface 5 4 1 GPS Antenna Interface The RF interface has an impedance of 500 To suit the physical design of individual applications SIM908 offers alternatives Recommended approach GPS RF connector GPS ANT pad If the GPS antenna connector is used the GPS ANT pad should be left not connected and the customer s main board under the GPS ANT pad should be copper keep out To minimize loss on the RF cable it need be very careful to choose cable SIMCom recommend the insertion loss should be meet following requirements e 5 lt 198 The customer s GPS antenna also can located in customer s main board and connect to module s GPS ANT pad through microstrip line or other type RF trace which impendence must be controlled in 500 MODULE GND Oe Matching circuit Antenna feed pad R101 GND m C101 C102 TENE E Eech Figure 40 GPS antenna matching circuit SIM908 Hardware Design V2 00 42 2012 05 07 In this figure
16. 2011 06 28 2011 08 26 2011 08 29 2011 09 02 2011 09 09 2011 09 22 2011 11 10 2011 12 13 2012 01 17 2012 02 21 2012 05 07 SIM908 Hardware Design V2 00 Version 1 00 1 01 1 02 1 03 1 04 1 05 1 06 1 07 1 08 1 09 2 00 Smart Machine Smart Decision Description of change Origin Correct the NC pins Correct the name of table 19 Modify antenna design guide Correct the figure 21 Add NC PIN53 Correct the pin44 name in figure 2 Modify GSM GPS antenna interface Add ESD design consideration Reinforce the explaining of the SIM Presence signal and AT commands about power saving mode Correct the page number delete Manufacturing chapter Add chapter 6 11 Module label information Add some notes in chapter 5 Author LiGang Ma Honggang Ye Haibing MA Honggang MA Honggang MA Honggang Ye Haibing Ma Honggang Ma Honggang Ma Honggang Ma Honggang 2012 05 07 060 060 eec A company of SIM Tech 1 Introduction Smart Machine Smart Decision This document describes SIM908 hardware interface in great detail This document can help user to quickly understand SIM908 interface specifications electrical and mechanical details With the help of this document and other SIM908 application notes user guide users can use SIM908 to design various applications quickly 2 SIM908 Overview Designed for global market SIM908 is integrated with a high performance GSM GPRS engine and GP
17. HOLDER 34 FIGURE 30 AMPHENOL 707 10 006 5122 SIM CARD HOLDER 34 FIGURE 31 MOLEX 9128 NM CARD HOLDER 35 FIGURE 32 REFERENCE CIRCUIT OF THE KEYPAD INTERFACE 36 FIGURE 33 OF VOICE CALLING AS A RECEIVER 37 FIGURE 34 RI BEHAVIOUR OF DATA CALLING AS A RECEIVER 38 FIGURE 35 RI BEHAVIOUR OF URC OR RECEIVE SMS 38 FIGURE 36 RI BEHAVIOUR AS A CALLER 38 FIGURE 37 REFERENCE CIRCUIT OF NETLIGH WE 39 FIGURE 38 THE RF INTERFACE OF MODULE eege 40 FIGURE 39 GSM ANTENNA MATCHING 40 MATCHING CIRCUL WE 42 FIGURE 41 MODULE LABEL INFORMATION 49 SIM908 Hardware Design_V2 00 2012 05 07 Version History Date
18. SIM Tech Appendix A Related Documents Table 34 Related documents SN 1 21 3 5 6 10 11 12 13 14 12 17 18 Document name SIM908 AT Command Manual AN_SIM900_TCPIP SIM900 Multiplexer User Manual Application Note AN SIM900 Series Update Tool UGD AN SIM900 AUDIO AN SIM900 Audio LINE IN input SIM900 Embedded AT Application Note AN Serial Port AN 51 900 Layout amp Schematic for Reference Module secondary SMT UGD ITU T Draft recommendation V 25ter GSM 07 07 new GSM 07 10 GSM 07 05 GSM 11 14 GSM 11 11 GSM 03 38 GSM 11 10 SIM908 Hardware Design_V2 00 Smart Machine Smart Decision Remark SIM908 AT Command Manual Applications User Manual SIM908 Multiplexer User Manual Application Note SIM908 Series Update Tool User Guide Applications Note About SIM908 Audio Applications Note About SIM908 LINE IN Input SIM908 Embedded AT Application Note Application Note About Serial Port Application Note About SIM908 TE PCB Layout amp Schematic Module secondary SMT User Guide Serial asynchronous automatic dialing and control Digital cellular telecommunications Phase 2 AT command set for GSM Mobile Equipment ME Support GSM 07 10 multiplexing protocol Digital cellular telecommunications Phase 2 Use of Data Terminal Equipment Data Circuit terminating Equipment DTE DCE interfac
19. all conditions for example no mobile fee or a invalid SIM card While you are in this condition and need emergent help please remember using emergency calls In order to make or receive calls the cellular terminal or mobile must be switched on and in a service area with adequate cellular signal strength Some networks do not allow for emergency call if certain network services or phone features are in use e g lock functions fixed dialing etc You may have to deactivate those features before you can make an emergency call Also some networks require that a valid SIM card be properly inserted in the cellular terminal or mobile SIM908_Hardware Design_V2 00 53 2012 05 07 eo of SIM Tech Smart Machine Smart Decision Contact us Shanghai SIMCom Wireless Solutions Ltd Add SIM Technology Building No 633 Jinzhong Road Changning District Shanghai P R China 200335 Tel 86 21 3252 3300 Fax 86 21 3252 3301 URL www sim com wm SIM908_Hardware Design_V2 00 54 2012 05 07
20. be disabled In this case the serial port 1s still accessible but all AT commands correlative with RF function and SIM card function will not be accessible For detailed information about AT Command AT CFUN lt fun gt please refer to document 1 Table 6 The current consumption of Minimum Functionality Mode fun Current consumption uA sleep mode 0 651 1 1500 4 DS 4 3 2 Sleep Mode T AT CSCLK 1 When the GPS function 15 shut off user can control SIM908 module to enter or exit the sleep mode 1 AT CSCLK 1 by DTR signal When DTR is in high level and without interrupt air and hardware such as GPIO interrupt or data in serial port SIM908 will enter sleep mode 1 automatically In this mode SIM908 can still receive paging or SMS from network but the serial port 1s not accessible Note For SIM906 it requests to set AT command AT CSCLK 1 and ensure DTR at high level to enable the sleep mode 1 the default value is 0 which can not make the module to enter sleep mode For more details please refer to document 1 4 33 Wake Up SIM908 from Sleep Mode 1 AT CSCLK 1 When SIM908 is in sleep mode AT CSCLK 1 the following methods can wake up the module SIM908 Hardware Design 2 00 23 2012 05 07 gt gt o 3 E m 3 Smart Machine Smart Decision Pull down DTR pin The serial port will be active after DTR pin 15 pulled to low level
21. component It is important to note that use of a LP antenna will result in a minimum of 3dB of gain loss when compared to a RHCP antenna at a defined elevation This is due to the right hand gain rule of antenna propagation Use of PIFA antenna is another LP possibility but the PIFA usually exhibits a considerable amount of gain nulls or holes in the radiation pattern This will be undesirable for obtaining a low circular error probability CEP since the antenna may not allow the receiver to capture the desired satellite at the ideal orientation due to these noted gain nulls Once again careful testing in an appropriate anechoic chamber 15 required If the customer s design is for automotive applications then an active antenna can be used and located on top of the car in order for guarantee the best signal quality GPS antenna choice should be based on the designing SIM908 Hardware Design 2 00 43 2012 05 07 ee ee Se lt product and other conditions Smart Machine Smart Decision For detailed Antenna designing consideration please refer to related antenna vendor s design recommendation The antenna vendor will offer further technical support and tune their antenna characteristic to achieve successful GPS reception performance depending on the customer s design 6 Electrical Reliability and Radio Characteristics 6 1 Absolute Maximum Ra
22. components R101 C101 and C102 is used for antenna matching components value only O Bn Smart Machine Smart Decision can be got after the antenna tuning Usually matching components value is provided by antenna vendor the default value of R101 is 00 and users need to reserve the place of C101 and C102 without soldering The traces in bold type should be treated as 50Q impedance controlled line in PCB layout 5 4 22 GPS Antenna Choice Consideration To obtain excellent GPS reception performance a good antenna will always be required The antenna 15 the most critical item for successful GPS reception in a weak signal environment Proper choice and placement of the antenna will ensure that satellites at all elevations can be seen and therefore accurate fix measurements are obtained Most customers contract with antenna design houses to properly measure the radiation pattern of the final mounted configuration In a plastic housing with associated components near the antenna Linear antennas are becoming more popular and the gain is reasonable since a smaller ground plane can be used User can consider following factors as Choose a linear antenna with a reasonably uniform hemispherical gain pattern of gt 4dB1 Use of an antenna with lower gain then this will give less than desirable results Please note that a RHCP antenna with a gain of 3dBi equates to
23. customized Please contact SIMCom for more details SIM908 Hardware Design V2 00 39 2012 05 07 ee 4 17 GSM Antenna Interface O Smart Machine Smart Decision The RF interface has an impedance of 50Q To suit the physical design of individual applications SIM908 offers alternatives Recommended approach GSM RF connector GSM ANT pad GPS_ANT PAD GSM GPS Antenna connector Antenna connector GSM ANT PAD SIr4968 S2 1047 K HMHP XXX XX TED II UNI C 0678 Figure 38 The RF interface of module If the GSM RF connector is used the GSM ANT pad should be left not connected the customer s main board under the GSM ANT pad should be copper keep out To minimize the loss on the RF cable 1 be very careful to choose cable SIMCom recommends the insertion loss should be meet following requirements GSM900 lt 1dB DCS1800 lt 1 54 The customer s GSM antenna also can be located in customer s main board and connect to modules GSM_ANT pad through microstrip line or other type RF trace which impendence must be controlled in 50Q To facilitate the antenna tuning and certification test a RF connector and an antenna matching circuit should be added The following figure is the recommended circuit MODULE RF test connector GND Matching circuit Antenna feed pad R101 R102 GND J102 Jeun
24. for about 50ms Receive a voice or data call from network Receive a SMS from network 4 3 4 Sleep Mode 2 AT CSCLK 2 Be sure that GPS function is closed then AT CSCLK 2 can set module to the sleep mode 2 In this mode SIM908 will continuously monitor the serial port data signal When there is no data transfer over 5 seconds on the RXD signal and there is no on air and hardware interrupts such as GPIO interrupt SIM908 will enter sleep mode 2 automatically In this mode SIM908 can still receive paging or SMS from network but the serial port is not accessible Note For SIM906 It is requested to set AT command AT CSCLK 2 to enable the sleep mode 2 the default value is 0 which can not make the module to enter sleep mode For more details please refer to document 1 4 3 5 Wake Up SIM908 from Sleep Mode 2 AT CSCLK 2 When SIM908 is in sleep mode 2 AT CSCLK 2 the following methods wake up the module Send data to SIM908 via main serial port Receive a voice or data call from network Receive a SMS from network Note The first byte of the user s data will not be recognized 4 4 Charging Interface SIM908 has integrated a charging circuit inside the module for Li Ion batteries charging control which make it very convenient for user s applications that support battery charging A common connection is shown in the following figure 5V VBAT Module Battery Pack TEMP
25. is remained Software is not active The serial port is not accessible Power supply connected to VBAT remains applied AT command AT CFUN be used to set the module to a minimum functionality mode Minimum without removing the power supply In this mode the RF part of the module will not work or functionality the SIM card will not be accessible or both RF part and SIM card will be closed and the mode serial port is still accessible The power consumption in this mode 15 lower than normal Charge only mode The module will enter Charge only mode automatically when a charger and battery are mode connected to a switched off SIM908 In this mode the module does not search for network and has limited access to available AT commands available The module can also enter Charge only mode from Charge mode during normal operation by normally powered down the module Charge mode The module will automatically go to this mode when a charger is connected to a Normal during normal operation mode module when battery voltage is not lower than 3 2V Normal operation mode operation includes SLEEP IDLE TALK GPRS IDLE and GPRS DATA SIM908 Hardware Design V2 00 11 2012 05 07 a Smart Machine Smart Decision Kl 23 SIM908 Functional Diagram The following figure shows a functional diagram of SIM908 The GSM baseband engine The GPS engine Flash The GSM radio frequency part The antenna interface
26. 1 10 37 y at 20278 1P 08 13 32 Plus 4 0 4 4 7 0 4 at 2 278 1R 18 4 750 4 at 20351 18 37 ta E Coaxial cable Receptacle Piue PAN 20311 18 08 gt __ 3 8 63 _ Plug j oa 2 5 MAX at 20278 18 08 13 32 2 5 at 20351 18 37 2 7 at 20278 1R 18 Receptacle Figure 6 U FL series RF adapter cable Unit mm SIM908_Hardware Design_V2 00 17 2012 05 07 060 060 eec A company of SIM Tech 4 GSM Application Interface Smart Machine Smart Decision 4 1 Power Supply The power supply range of SIM908 is from 3 2V to 4 8V The transmitting burst will cause voltage drop and the power supply must be able to provide sufficient current up to 2A For the VBAT input a bypass capacitor low ESR such as a 100 uF is strongly recommended this capacitor should be placed as close as possible to SIM908 VBAT pins The following figure is the reference design of 5V input power supply The designed output for the power supply 15 4 1V thus a linear regulator can be used DC INPUT 0101 MIC29302 FB101 VB T 270 OHM Figure 7 Reference circuit of the LDO power supply If there is a high drop out between the input and the desired output VBAT a DC DC power supply will be preferable because of its better efficiency especially with the 2A peak current in burst mode of the module The following figure is the reference c
27. 2 00 2 2012 05 07 gt 3 E m 5 Be 2095999 5 8 Smart Machine Smart Decision Contents di 3 E 7 I Introduction E n 8 PEE WE ONENI 8 2 1 SIM908 Kovkeatures 8 2 2 Operan ERR RR RR amm 11 23 SIM905 BITS a o nm 12 3 Package EE un WE WE 13 3 1 Pron Di A EE E TE 13 3 2 BIS cie e EET W 14 3 3 126 eene 16 3 4 Mechanical Dimensions of the RF Connector 17 4 GSM Application Interface 18 4 1 Joi lipa 18 411 Miuinimizing Voltage Drop of 19 4 1 2 Monitoring Power Supply E 19 4 2 Powet on down SCC MOS uuu u E 19 2 WM EE Lo rr Jh E 19 4 2 2 Power down 51 908 21 4 2 3 Restart SIM908 by PWRKEY gt 220002020245 27 4 3 Power
28. 2 00 37 2012 05 07 gt 3 E 3 5 209999 5 8 Smart Machine Smart Decision RI HIGH Establish the call Hang up the call Idle Ring Figure 34 RI behaviour of data calling as a receiver HIGH RI 120mS LOW Idle Receive SMS URC Figure 35 RI behaviour of URC or receive SMS However if the module is used as caller the RI will remain high Please refer to following figure HIGH LOW Idle Ring Establish Hang up Idle the call the call Figure 36 RI behaviour as a caller 4 13 Network Status Indication The NETLIGHT pin can be used to drive a network status indication LED The status of this pin is listed in following table Table 17 Status of the NETLIGHT pin Status SIM908 behavior Off SIM908 is not running 64ms On 800ms Off SIM908 not registered the network 64ms On 3000ms Off SIM908 registered to the network 64ms On 300ms Off PPP GPRS communication is established A reference circuit is recommended in the following figure SIM908_Hardware Design_V2 00 38 2012 05 07 gt 3 E m 5 Be 209999 5 8 Smart Machine Smart Decision MODULE VBAT NETLIGHT Figure 37 Reference circuit of NETLIGHT 4 14 General Purpose Input Output GPIO SIM908 provides up to 6 GPIO pins The output voltage level of the GPIO can set by the command A T SGPIO The
29. 8 battery charging happens after detecting charger supply and the presence of battery If there is no charger supply or no battery present charging function will not be enabled Normally there are three main states in the whole charging procedure DDLO charge Pull up mode and UVLO charge Pre charge mode Fast charge DDLO charge and UVLO charge DDLO 1s the state of battery when its voltage is under 1 5V And UVLO means the battery voltage 15 less than 3 3V and more than 1 5V The battery is not suitable for fast charging when its condition is DDLO or UVLO The SIM908 provides a small constant current to the battery when the battery is between DDLO and In DDLO charging state SIM908 gives out ImA current to the battery And in UVLO charging state SIM908 provides about less than 200mA current to the battery DDLO charging terminates when the battery voltage reaches 1 5 V UVLO charging terminates when the battery voltage 15 up to 3 3V Both DDLO and UVLO charge are controlled by the SIM908 hardware only Fast charge If there is a charger supply and battery present and the battery is notin DDLO and UVLO SIM908 will enter fast charge state Fast charge is controlled by the software to make the current voltage regulation The charging scheme for the Li Ion battery is constant current about 550mA first followed by constant voltage charging once 4 2V 1s reached Charging is stopped when the charging current at constant voltage
30. EQUENCIES 49 TABLE 332Z1N USNISRATION OF MODULE LABEL E 50 JADBLPEO4 RELM ED DOC RA OCH KE 51 TABLE 35 AND ABBREVIATIONS EE 52 KE E 53 SIM908 Hardware Design_V2 00 5 2012 05 07 Smart Machine Smart Decision Figure Index FIGURE 1 SIM908 FUNCTIONAL DIAGRAM 17 FIGURE 2 SIM908 PIN OUT DIAGRAM TOP VIEW Keser eege a Een Gerd eegen Up Spe eng 13 FIGURE 3 DIMENSIONS OF SIM908 4 UNIT MM D Abee 16 FIGURE 4 RECOMMENDED PCB FOOTPRINT OUTLINE UNIT MM 16 FIGURE S HC HR bilo rcc 17 FIGURE 6 SERIES RF ADAPTER CABLE UNIT MM aassasssssssssssssssa 17 FIGURE 7 REFERENCE CIRCUIT OF THE LDO POWER SUPPLY 18 FIGURE 8 REFERENCE CIRCUIT OF THE DC DC POWER SUPPLY 18 FIGURE 9 VBAT VOLTAGE DROP DURING TRANSMIT 57 19 FIGURE 10 THE MINIMAL VBAT VOLTAGE REQUIREMENT AT VBAT DROP eee 19 FIGURE 11 POWERED ON DOWN MODULE USING TRANSISTOR E 19 FIGURE 12 POWERED ON DOWN MODULE USING BUTTON 20 FIGURE 13 TIMIN
31. G OF POWER ON Nene 20 FIGURE 14 TIMING OF POWER DOWN SIM908 BY 2 FIGURE 15 TIMING OF RESTART SIM908 ageet 22 FIGURE 16 SIM908 WITH BATTERY CHARGER AND PACK CONNECTION 24 FIGURE 17 RTC SUPPLY FROM 28 FIGURE 18 RTC SUPPLY FROM NON CHARGEABLE BATTERY 28 FIGURE 19 SUPPLY FROM RECHARGEABLE BATTERY 28 FIGURE 20 SEIKO XHA414H IVOIE CHARGE DISCHARGE CHARACTERISTIC eene 28 FIGURE 21 CONNECTION OF THE SERIAL INTERFACES A See 29 FIGURE 22 CONNECTION OF RXD AND TXD ONLY amp W RZ 29 FIGURE 23 CONNECTION FOR SOFTWARE UPGRADING AND DEBUGGING rmm 30 FIGURE 24 SPEAKER REFERENCE CIRCUL EN TE 3l FIGURE 25 SPEAKER WITH AMPLIFIER REFERENCE CIRCUIT 3l FIGURE 26 MICROPHONE REFERENCRCICOILTL 32 FIGURE 27 EARPHONE 32 FIGURE 28 REFERENCE CIRCUIT OF THE 8 PIN SIM CARD HOLDER 33 FIGURE 29 REFERENCE CIRCUIT OF THE 6 PIN SIM CARD
32. Interface SIM908 provides a serial LCD display interface It could also be used as SPI interface in the embedded application For details about embedded AT application please refer to document 7 Note This function is not supported in the standard firmware If user wants this function the firmware must be customized Please contact SIMCom for more details 4 10 Keypad Interface The keypad interface consists of 3 keypad column outputs and 3 keypad row inputs The basic configuration is 3 keypad columns and 3 keypad rows total 9 keys Table 14 Pin definition of the keypad interface Pin name Pin number Default function Second function Default state KBRO 31 GPIOI Output Pull down GPIO2 KBRI 32 GPIO2 Output Pull down GPIO3 KBR2 33 GPIO3 Output Pull down Keypad matrix 4 34 GPIO4 Output Pull down 5 KBC1 35 GPIOS Output Pull down GPIO6 2 36 GPIO6 Output Pull down The keypad interface allows a direct external matrix connection A typical recommended circuit of the keypad is shown in the following figure MODULE KBC1 i KBC20 1 S i L KBR0OO 2 I ak KBR16 pp p a I L L KBR2O E uis n Sg ES 1 Figure 32 Reference circuit of keypad interface Note This function is not supported in the standard firmware If user wants this function the firmware must be customized Please
33. KEY FEATURES uuu 8 TABLE 2 GPS ENGINE PERFORMANCE EE 10 TABLE 3 CODING SCHEMES AND MAXIMUM NET DATA RATES OVER AIR INTERFACE 10 TABLE 4 OVERVIEW OF OPERATING MODES 11 PINDE S RhIPIN eegen 14 TABLE 6 THE CURRENT CONSUMPTION OF MINIMUM FUNCTIONALITY MOPE 23 TABLE 7 SPECIFICATION OF RECOMMENDED BATTERY PACK 25 TABLES CHARGE OPERATING MODES on tin ctn edo eer gettin cta ue abu ed ee edu ea 26 TABLE 9 AT COMMAND USUALLY USED IN CHARGE ONLY MODERN 27 TABLE 10 MICROPHONE INPUT CHARACTERISTICS Mae 32 TABLE 11 AUDIO OUTPUT CHARACTERISTICS 33 TABLE 12 PIN DESCRIPTION AMPHENOL SIM CARD HOLDER 35 TABLE 13 PIN DESCRIPTION MOLEX SIM CARD HOLDER 35 TABLE 14 PIN DEFINITION OF IHEKEYRAIDINTRREACR 36 TABLE S ADG RTE CR WEEN 37 TABLE 16 RILBEHAVIORS Em 37 TABLE 17 SEATUS OF THE NETLIGHT PIN TN A 38 TABLE 18 PIN DEFINITION OF THE GPIO 39 TABLE 19 AT COMMANDS FOR GPS FUNCTION
34. S engine The GSM GPRS engine is a quad band GSM GPRS module that works on frequencies GSM 850MHz EGSM 900MHz DCS 1800MHz and PCS 1900M Hz SIM908 features GPRS multi slot class 10 class 8 optional and supports the GPRS coding schemes CS 1 CS 2 CS 3 and CS 4 The GPS solution offers best in class acquisition and tracing sensitivity Time To First Fix TTFF and accuracy With a tiny configuration of 30 30 3 2mm SIM908 can meet almost all the space requirements in user applications such as M2M smart phone PDA tracker and other mobile devices SIM908 has 80 SMT pads and provides all hardware interfaces between the module and customers boards Serial port and debug port can help user easily develop user s applications e GPS Serial port Two audio channels include two audio inputs and two audio outputs These can be easily configured by AT command Charging interface Programmable general purpose input and output The keypad and SPI display interfaces will give users the flexibility to develop customized applications and connector interface SIM908 is designed with power saving technique so that the current consumption is as low as 1 2mA sleep mode GPS engine is powered down SIM908 integrates TCP IP protocol and extended TCP IP AT commands which are very useful for data transfer applications For details about TCP IP applications please refer to document 2 21 51 908 Key Feat
35. Y This procedure makes the module log off from the network and allows the software to enter into a secure state to save data before completely shut down Before the completion of the power down procedure the module will send URC NORMAL POWER DOWN At this moment AT commands can not be executed any more and only the RTC is still active Power down mode can also be indicated by STATUS pin which is at low level at this time 4 2 2 2 Power down SIM908 by AT Command SIM908 can be powered down AT command AT CPOWD I This procedure makes the module log off from the network and allows the software to enter into a secure state to save data before completely shut down Before the completion of the power down procedure the module will send URC NORMAL POWER DOWN At this moment AT commands can not be executed any more and only the RTC is still active Power down mode can also be indicated by STATUS pin which 15 at low level at this time For detail about the AT command AT CPOWD please refer to document 1 SIM908 Hardware Design V2 00 21 2012 05 07 ee ee of SIM Tech 4 2 2 3 Over voltage or Under voltage Power down Smart Machine Smart Decision The module software monitors the VBAT voltage constantly If the voltage lt 3 3V the following URC will be reported UNDER VOLTAGE WARNNING If the voltage gt 4 7V the following URC will be reported OVER VOLTAGE WARNNING If the v
36. YLEVER MUST NOT PROTRUDE BEYOND HOUSING EDGE IM THIS AREA 4 TAILS OM EACH SIDE OF CONNECTOR LIE WITHIN G l2mm OF EACH OTHER 26 0 REF 31 0Q 05 LIQUID CRYSTAL POLYMER LCP 302 GLASS FILL ULS4 0 COLOUR BLACK 0 15 PHOSPHOR BRONZE O lum MIN OVER TAILS CONTACT AREA TERMINAL doum MIN 5n ON SMT PUSH BUTTON 1 NYLON 46 YELLOW M COIL SPRING 0 25 STAINLESS STEEL 2 0 4 STAINLESS STEEL fern STEEL N LEVER 1 0 4 STAINLESS STEEL 2 0 5 THIRD ANGLE PROJECTION C BEVISE ONLY ON CAD SYSTEM s REV TR DIVEMNTIM PEVENITE TYP CONT HEIGHT B ded BHEE MUT NE MITHIRIT BEETTLM SIM PCB CONNECTOR E BT RER iT OTE eee See seg ui EUROPE lo sree More 31228 0001 nm 91228 Figure 31 Molex 91228 SIM card holder Table 13 Pin description Molex SIM card holder Pin Signal Description C1 SIM VDD SIM card power supply 2 SIM RST SIM card reset C3 SIM CLK SIM card clock C4 GND Connect to GND C5 GND Connect to GND C6 VPP Not connect SIM908_Hardware Design_V2 00 35 2012 05 07 ee ee W Smart Machine Smart Decision Cy SIM DATA SIM card data I O C8 SIM PRESENCE Detect SIM card presence 4 9 LCD Display SPI
37. a linear polarized antenna of OdBi Proper ground plane sizing 15 a critical consideration for small GPS antennas Proper placement of the GPS antenna should always bethe FIRST consideration in integrating the SIM908 GPS Module If the customer s design will allow for a ceramic RHCP patch antenna with an appropriately sized ground plane and the patch is normally oriented towards the sky then that particular solution usually works the best Note that if the patch antenna ground plane 15 less han 60x60mm then compromises to the beam width and gain pattern could result Usually the gain becomes very directional and looses several dB of performance Since results can vary measuring the antenna radiation pattern in the final housing in an appropriate anechoic chamber is required Some customers do not have the size availability to implement a patch antenna approach In that instance use of a Linear Polarized LP antenna 1s the next best alternative There are new ceramic LP antennas the market that exhibit reasonable gain characteristics once properly mounted in the housing and when matched to an appropriate sized ground Generally the ground plane requirements are smaller for a LP antenna when compared to a patch but once again proper testing in an anechoic chamber is a mandatory requirement These ceramic elements will need to be located near the end of the ground plane and will require several millimeters of clearance between the closest
38. acteristics 2 e 2 6 6 SIM VDD Characters Table 25 SIM VDD ics N 2 3 lt gt ei c e A Table 26 VRTC characteristics MN Ka E e e 2 lt r2 N 45 00 060 of SIM Tech Smart Machine Smart Decision 6 8 Current Consumption VBAT 3 8V GPS engine is powered down Table 27 GSM current consumption Symbol Parameter Conditions Value Unit VRTC current disconnects Backup battery is 3 V p uA Power down mode 50 uA BS PA MFRMS 9 1 2 Sleep mode BS PA MFRMS 5 1 5 mA BS PA MFRMS 2 1 7 GSM 850 EGSM 900 Idle mode 2 mA DCS 1800 PCS 1900 PCL 5 240 GSM 850 e m EGSM 900 PCL 19 76 Voice call mA PCL 0 180 DCS 1800 m PCS 1900 PCL 15 76 PCL 5 240 PCL 12 110 mA Pe VBAT current EGSM 900 _ Data mode PCL 19 83 GPRS 1Rx 1Tx PCL 0 170 DCS 1800 T PCS 1900 GE 29 PCL 15 80 PCL 5 270 GSM 850 SC EGSM 900 nore 20 Data mode PCL 19 120 GPRS 4Rx 1 Tx PCL 0 210 DCS 1800 porum m PCS 1900 MOLES 115 ie 435 GSM 850 F A EGSM 900 aee is Data mode PCL 19 130 GPRS 3Rx 2Tx PCL 0 320 DCS 1800 mA PCS 1900 a 2 PCL 15 22 Peak current During Tx burst 2 A In above table the current consumption value is the ty
39. ata Communication Equipment The following figure shows the connection between module and client DTE MODULE DCE CUSTOMER DTE Serial port Serial port TXD gt RXD ume RXD RTS RTS CTS Ee CTS DTR 04 DTR DCD lt DCD RI gt O RING Debug port Serial port2 GPS DBG_TX 202 TXD GPS DBG_RX 2 RXD Figure 21 Connection of the serial interfaces If only RXD and TXD are used in user s application other serial pins should be kept open Please refer to following figure MODULE DCE CUSTOMER DTE Serial port Serial port1 TXD lt TXD RXD Pan E RXD RTS 406 7 o RTS CTS CTS ox DTR DOD o DCD RI Q X O RING Debug port Serial port2 GPS DBG TX ues TXD GPS DBG gt RXD Figure 22 Connection of RXD and TXD only 4 6 1 Function of Serial Port and Debug Port Serial port Full modem device Contains data lines TXD and RXD hardware flow control lines RTS and CTS status lines DCD and RI Serial port can be used for CSD FAX GPRS service and AT communication It can also be used for multiplexing function For details about multiplexing function please refer to document 3 Serial port supports the following baud rates 1200 2400 4800 9600 19200 38400 57600 and 115200bps Autobauding only supports the following baud rates 1200 2400 4800 9600 19200 38400 and 57600bps e The d
40. automatically 4 4 2 Recommended Battery Pack Following is the specification of recommended battery pack Table 7 Specification of recommended battery pack Items Description Battery type Li ion Manufacturer Jiade Energy Technology Normal voltage 3 7V Capacity NORMAL 1100mAh Charge Voltage 4 200 0 050V Max Charge Current 1 0C Charge Method CC CV Constant Current Constant Voltage Max Discharge Current 1 0C for continuous discharging mode Discharge Cut off Voltage 3 0V cell Internal resistance Initial lt 130mQ 4 4 3 Implemented Charging Technique SIM908 has battery charging function There are three pins related to the battery charging function there are VCHG VBAT and TEMP BAT ADCO pins The VCHG Pin is driven by an external voltage system can use this Pin to detect a charger supply and provide most charging current through SIM908 module to battery when charging 15 in fast charge state VBAT pin gives charging current to external battery from SIM908 module TEMP Pin is for user to measure the battery temperature Let this Pin open if battery temperature measurement is not user s design concern SIM908_Hardware Design_V2 00 25 2012 05 07 ee Smart Machine Smart Decision It is very simple to implement charging function user just needs to connect the charger to the VCHG Pin and connect the battery to the VBAT Pin SIM90
41. contact SIMCom for more details SIM908_Hardware Design_V2 00 36 2012 05 07 eo of SIM Tech 4 11 ADC Smart Machine Smart Decision SIM908 provides an auxiliary ADC which can be used to measure the voltage User can use AT command to read the voltage value For details of this AT command please refer to document 1 Table 15 ADC specification Parameter Min Unit Voltage range 0 2 8 V ADC Resolution 10 bits Sampling rate 200K Hz 4 12 RI Behaviors Table 16 RI behaviors State RI response Standby High The pin is changed to low When any of the following events occur the pin will be changed to high 1 Establish the call 2 Hang up the call Voice call The pin is changed to low When any of the following events occur the pin will be changed to high 1 Establish the call 2 Hang up the call Data call SUIS The pin is changed to low and kept low for 120ms when a SMS is received Then it is changed to high URE The pin is changed to low and kept low for 120ms when some URCs are reported Then it is changed to high For more details please refer to document 8 The behavior of the RI pin is shown in the following figure when the module is used as a receiver RI HIGH Establish the call Hang up the call LOW Idle Ring Figure 33 RI behaviour of voice calling as a receiver SIM908_Hardware Design_V
42. differential signal layout rules MODULE These components should be placed to speaker as close as possible Thelines in bold type should be accorded to differential signal layout rules ESD ANTI Amplifier H SPK2P Circuit MODULE Figure 25 Speaker with amplifier reference circuit SIM908_Hardware Design_V2 00 31 2012 05 07 i 995 an Smart Machine Smart Decision 4 7 2 Microphone Interfaces Configuration These components should be placed to microphone as close as possible The lines in bold type should ESD Y BM be accorded to differential ANTI signal layout rules MIC1P Electret MODULE Microphone Figure 26 Microphone reference circuit Microphone input also could be used to LINE IN input For details please refer to document 6 4 7 3 Earphone Interface Configuration Close to socket The lines in bold type should be accorded to differential signal layout rules Close to module 4 MODULE duF 5 2 3 M 33pF 10pF ESD 4 N 33pF ANTI _ gt Hei 1 1 Amphenol 9001 8905 050 Figure 27 Earphone reference circuit 4 7 4 Audio Elec
43. e for Short Message Service SMS and Cell Broadcast Service CBS Digital cellular telecommunications system Phase 2 Specification of the SIM Application Toolkit for the Subscriber Identity Module Mobile Equipment SIM ME interface Digital cellular telecommunications system Phase 2 Specification of the Subscriber Identity Module Mobile Equipment SIM ME interface Digital cellular telecommunications system Phase 2 Alphabets and language specific information Mobile Station Part 1 Conformance specification Digital cellular telecommunications system Phase 2 MS conformance specification 51 2012 05 07 Qoe 06 of SIM Tech B Terms and Abbreviations Smart Machine Smart Decision Table 35 Terms and Abbreviations SIM908_Hardware Design_V2 00 2012 05 07 ee ee ech E CQheeee lt Smart Machine Smart Decision URC Unsolicited Result Code USSD Unstructured Supplementary Service Data Phonebook abbreviations FD SIM fix dialing phonebook LD SIM last dialing phonebook list of numbers most recently dialed MC Mobile Equipment list of unanswered MT calls missed calls ON SIM or ME own numbers MSISDNs list RC Mobile Equipment list of received calls SM SIM phonebook NC Not connect C Safety Caution Table 36 Safety caution Requirements When in a hospital or other health care facility obse
44. eed 30dBm and at the maximum power level the output power tolerance should not exceed 2dB under normal condition and 2 54 under extreme condition SIM908 Hardware Design V2 00 48 2012 05 07 ee of SIM Tech 6 10 2 Module RF Receive Sensitivity Smart Machine Smart Decision The following table shows the module s conducted receive sensitivity it is tested under static condition Table 31 SIM908 conducted RF receive sensitivity GSM850 109dBm 107dBm EGSM900 109dBm 107dBm DCS1800 109dBm 107dBm PCS1900 109dBm 107dBm 6 10 3 Module Operating Frequencies The following table shows the module s operating frequency range it is followed by the 3GPP TS 05 05 technical specification requirement Table 32 SIM908 operating frequencies GSM850 869 894MHz 824 849 MHz EGSM900 925 960MHz 880 915MHz DCS1800 1805 1880MHz 1710 1785MHz PCS1900 1930 1990M Hz 1850 1910 72 6 11 Module label information The following figure marked information of SIM900 module IMEI 861001000232336 E e T w i 1 LI 41109 AEE Figure 41 Module label information SIM908_Hardware Design_V2 00 49 2012 05 07 of SIM Tech Smart Machine Smart Decision Acompany Table 33 illustration of module label SIM908 Hardware Design_V2 00 50 2012 05 07 ee ee of
45. efault setting is autobauding SIM908_Hardware Design_V2 00 29 2012 05 07 Qeeee Smart Machine Smart Decision Autobauding allows SIM908 to automatically detect the baud rate of the host device Pay more attention to the following requirements Synchronization between DTE DCE When DCE powers on with autobauding enabled user must firstly send character A to synchronize the baud rate It is recommended to send AT until DTE receives the OK response which means DTE and DCE are correctly synchronized For more information please refer to the AT command AT IPR Restrictions of autobauding operation The DTE serial port must be set at 8 data bits no parity and 1 stop bit The URC such as CFUN 1 and READY will not be reported Note User can use AT command AT IPR x to set a fixed baud rate and the setting will be saved to non volatile flash memory automatically After the configuration is set as fixed baud rate the URC such as RDY CFUN 1 and CPIN READY will be reported when SIM908 is powered on Debug port Used for debugging and upgrading firmware Debug port supports the baud rate of 115200bps 4 6 3 Software Upgrade and Debug Refer to the following figure for debugging and upgrading software MODULE RS232 PC GPS DBG TXD O l y K v y O TXD IN TXD OUT O O RXD GPS DBG_RXD O RXD OUT
46. er SIMCom recommends to use Amphenol C707 10 006 5122 User can visit http www amphenol com for more information about holder MAX 30 1 OPTIONAL POLES FOR PRODUCTION 9 8 E r3 Br NM 1 L K PHENOL AS H ISINLOCIO OU C7 W d 6 e H D IL anm e Ft tm Ers Ge 1 el L A O e i aim e 215 WP HR 1 V n P H ors i 2 Ke A 4 p 2 W P Lea DEE lt a poem Ss E C vet wet 2 mer 0003 Figure 30 Amphenol C707 10M006 5122 SIM card holder SIM908 Hardware Design_V2 00 34 2012 05 07 B Smart Machine Smart Decision Table 12 Pin description Amphenol SIM card holder Pin name Signal Description CH SIM VDD SIM card power supply e SIM RST SIM card reset C3 SIM CLK SIM card clock C5 GND Connect to GND C6 VPP Not connect C7 SIM DATA SIM card data I O For 8 pins SIM card holder SIMCom recommends to use Molex 91228 User can visit http www molex com for more information about the holder KN 17 s s 4 5 F ge E E d ot 2 314 XB 3 0 REF FULL STROKE 2 0 SDA 91228 2 54 PITCH 0 4 REF HSG EDGE RECOMMENDED PCH LAYOUT 2 NOTES SEE PRODUCT SPECIFICATION 5 99020 007 2 PACKING TAPE AND REEL FOR DETAIL SEE amp 91228 9001 5 3 PUSH ROG
47. has decreased down to the pre set current 4 4 4 Operating Modes during Charging The battery can be charged during various operating mode That means that charging can be in progress while SIM908 is in Normal mode SLEEP IDLE TALK GPRS IDLE or GPRS DATA mode In this case the voltage supply should be sufficient Here Charging Normal mode is named as Charge mode If the charger is connected to the module s VCHG Pin and the battery is connected to the VBAT Pin while SIM908 is in POWER DOWN mode 51 908 will go into the Charge only mode The following table gives the difference between Charge mode and Charge only mode Table 8 Charge operating modes How to activate mode Features Connect charger to module s VCHG GSM remains operational and registers to GSM and connect battery to VBAT Pin of network while charging is in progress 3 module while SIM908 is in Normal The serial interfaces are available in IDLE TALK 2 operating mode including IDLE TALK mode the AT command set can be used fully in this mode SLEEP mode etc case 5 In SLEEP mode the serial interfaces are not available Once the serial port 15 connected and there is data in transferring SIM908 will exit the SLEEP mode SIM908_Hardware Design_V2 00 26 2012 05 07 gt 3 E m E 2095999 2 5 5 8 Smart Machine Smart Decision 2 Connect charger to module s VCHG Battery can be charged whe
48. input voltage level of the GPIO can also be read by the AT command A T SGPIO For more details please refer to document 1 Table 18 Pin definition of the GPIO interface Pin name Pin number Default function Second function Default state GPIO1 31 GPIOI KBRO Output pull down GPIO2 KBRI D2 GPIO2 KBRI Output pull down GPIO3 KBR2 33 GPIO3 KBR2 Output pull down GPIO4 34 GPIO4 KBCO Output pull down GPIO5 35 GPIOS KBCI Output pull down GPIO6 KBC2 36 GPIO6 KBC2 Output pull down 4 15 PWM SIM908 provides 3 PWMSs which can be used to drive a vibrator and a backlight LED for display or keyboard Each PWMI and PWM2 output frequency varies from 25 6KHz to 3 25MHz Two 7 bit unsigned binary parameters are used for the output period and for the duty cycle The PWM3 for the buzzer outputs a square wave at the desired tone frequency The tone frequencies are programmable from 200 Hz to 5 kHz and can be re programmed on the fly to generate monophonic audio ring tones or alert tones The tone level can be adjusted over a 24 dB range in 4 dB steps or it can be muted The AT command SPWM is used to set the output period and duty cycle of PWM For details please refer to document 1 4 16 Bus The SIM908 provides an interface which is only used in the embedded AT application Note This function is not supported in the standard firmware If user wants this function the firmware must be
49. ircuit DC U101 LM2596 ADJ L101 FB101 VBAT ox o e t vin Vout 2 e Y Y Y _ e e 100uH 270 OHM ON TVS101 A core ON FB 102 emt 104 E SMBJ15A 100 eet A 330uF 100nF MBR360 1K Figure 8 Reference circuit of the DC DC power supply The single 3 7V Li ion cell battery can be connected to SIM908 VBAT pins directly But the Ni Cd or Ni MH battery must be used carefully since their maximum voltage can rise over the absolute maximum voltage of module and damage it When battery is used the total impedance between battery and VBAT pins should be less than 150mQ The following figure shows the VBAT voltage drop at the maximum power transmit phase and the test condition is as following VBAT 4 0V bypass capacitor Ca 100uF tantalum capacitor ESR 0 7Q Another VBAT bypass capacitor Cg 1uF SIM908 Hardware Design V2 00 18 2012 05 07 gt 5 3 E m E Be 209999 5 5 8 Smart Machine Smart Decision 577u8 4 615mS m gt E Burst 2A VBAT VBAT Max 300mV Figure 9 VBAT voltage drop during transmit burst 4 1 Minimizing Voltage Drop of VBAT When designing the power supply in u
50. n GSM engine is not while SIM908 is in POWER DOWN registered to GSM network mode Only afew AT commands is available as listed IMPORTANT Here Charge only mode is below Eu charging when power 15 down it means 5 that not all software tasks are running Note VBAT can not provide more than 5mA current while SIM908 module is during the DDLO charge state In other words it is strongly recommended that VBAT should not be the main power supply in the application subsystem if SIM908 DDLO charging State occurs Table 9 AT command usually used in Charge only mode AT command Function AT CCLK Set data and time of AT CPOWD Power down AT CBC Indicated charge state and voltage AT CFUN Start or close the protocol Set AT command AT CFUN 1 module can be transferred from Charge only mode to Charging in normal mode In Charge only mode the default value 15 0 4 4 5 Charger Requirements Following is the requirements of charger for SIM908 Simple transformer power plug Output voltage 5 0 6 Minimum supply current 750mA A 10V peak voltage is allowed for maximum 1ms when charging current is switched off A 1 6A peak current is allowed for maximum 1105 when charging current is switched on 4 5 RTC Backup Current input for RTC when the VBAT 15 not supplied for the system Current output for backup battery when the VBAT power supply is in present and the backup battery is in low vol
51. oltage lt 3 2V the following URC will be reported and the module will be automatically powered down UNDER VOLTAGE POWER DOWN If the voltage gt 4 8V the following URC will be reported and the module will be automatically powered down OVER VOLTAGE POWER DOWN At this moment AT commands can not be executed any more and only the RTC 1s still active Power down mode can also be indicated by STATUS pin which is at low level at this time 4 2 2 4 Over temperature or Under temperature Power down The module will constantly monitor the temperature of the module If the temperature gt 80 C the following URC will be reported CMTE 1 If the temperature lt 30 following URC will be reported CMTE 1 If the temperature gt 85 the following URC will be reported and the module will be automatically powered down CMTE 2 If the temperature lt 40 the following URC wull be reported and the module will be automatically powered down CMTE 2 At this moment AT commands can not be executed any more and only the RTC 1s still active Power down mode can also be indicated by STATUS pin which is at low level at this time The AT command AT CMTE could be used to read the temperature when the module is running For details please refer to document 1 4 2 3 Restart SIM908 by PWRKEY Pin When the module works normally if the user wants to restart the module follow the procedure below 1 Powerdown the module
52. pical one of the module tested in laboratory In the mass production stage there may be differences among each individual SIM908_Hardware Design_V2 00 46 2012 05 07 of SIM Tech Smart Machine Smart Decision 6 9 Electro Static Discharge SIM908 is an ESD sensitive component so more attention should be paid to the procedure of handling and packaging The ESD test results are shown in the following table Table 28 The ESD characteristics Temperature 25 C Humidity 45 Note It is suggested that customers in serials with 100ohm resistances on UART lines ta 6 10 Radio Characteristics SS 6 10 1 Module RF Output Power The following table shows the module conducted output power it is followed by 3GPP TS 05 05 technical specification requirement Table 29 SIM908 GSM 900 and ies conducted RF output power amp SIM908_Hardware Design_V2 00 N 2012 05 07 of SIM Tech Smart Machine Smart Decision For the module s output power the following should be noted At GSM900 and 5 850 band the module is a class 4 device so the modules output power should not exceed 33dBm and at the maximum power level the output power tolerance should not exceed 2dB under normal condition and 2 54 under extreme condition At DCS1800 and PCS1900 band the module is a class 1 device so the module s output power should not exc
53. reference circuit of the 8 pin SIM card holder is illustrated in the following figure VDD EXT SIM_VDD MOLEX 9 1228 SIM_RST VCC GND SIM_CLK 5 IM PRESENCE RST VPP CLK LO PRESENCE GND MODULE SIM DATA Figure 28 Reference circuit of 8 pin SIM card holder Note The SIM Presence is multiplexing with KBCO PIN 34 SIM908 Hardware Design V2 00 B3 2012 05 07 Sch ecce 2 Smart Machine Smart Decision The SIM PRESENCE is used for detection of the SIM card hot plug in User can select the 8 pin SIM card holder to implement SIM card detection function AT command AT CSDT is used to enable or disable SIM card detection function For details of this AT command please refer to document 1 If the SIM card detection function is not used user can keep the SIM PRESENCE pin open The reference circuit of 6 pin SIM card holder is illustrated in the following figure 100nF SIM SIM_VDD VCC GND SIM_RST 22R TSIM CIK RST VPP MODULE CLK IO C707 10M006 5122 I 7 SMFO5C L SIM DATA Figure 29 Reference circuit of the 6 pin SIM card holder 4 8 2 Design Considerations for SIM Card Holder For 6 SIM card hold
54. result code as following when fixed baud rate set RDY CHARGE ONLY MODE When user drives the PWRKEY of Charge only mode SIM908 to a low level voltage for a period of time please refer to Figure 13 Timing of power on module the SIM908 will power up and go into Charge mode during normal operation In this case SIM908 sends out result code as following SIM908 Hardware Design V2 00 20 2012 05 07 eo 060 of SIM Tech Smart Machine Smart Decision From CHARGE ONLY MODE to NORMAL MODE In Charge mode during normal operation all operations and AT commands are available 4 2 2 Power down SIM908 SIM908 will be powered down in the following situations Normal power down procedure power down SIM908 by the PWRKEY pin Normal power down procedure power down SIM908 by AT command AT CPOWD 1 Abnormal power down over voltage or under voltage automatic power down o Abnormal power down over temperature or under temperature automatic power down 4 2 2 1 Power down SIM908 by the PWRKEY Pin User can power down SIM908 by pulling down the PWRKEY pin for at least 1 second and release Please refer to the power on circuit The power down scenario is illustrated in following figure 5S gt Pulldown gt 15 Delay gt 1 75 I I PWRKEY n gp Input Logoff net gt 2 4V STATUS Output Serial Port Active X Undefined Figure 14 Timing of power down SIM908 by PWRKE
55. roadcast Control Channel PBCCH Support CSD transmission Unstructured Supplementary Services Data USSD support MT MO CB Text and PDU mode SMS storage SIM card Group 3 Class 1 Support SIM card 1 8V 3V Antenna pad Speech codec modes Half Rate ETS 06 20 Full Rate ETS 06 10 Enhanced Full Rate ETS 06 50 06 60 06 80 Adaptive multi rate AMR Echo Cancellation Noise Suppression Serial port Full modem interface with status and control lines unbalanced asynchronous 1200bps to 115200bps Can be used for AT commands or data stream Support RTS CTS hardware handshake and software ON OFF flow control Multiplex ability according to GSM 07 10 Multiplexer Protocol Autobauding supports baud rate from 1200 bps to 57600bps Debug port Null modem interface GPS DBG TXD and GPS DBG RXD Can be used for debugging and upgrading firmware Support phonebook types SM FD LD RC ON MC GSM 11 14 Release 99 support RTC Size 30 30 3 2mm Weight 5 2g Firmware upgradeable by debug port SIM908 does work at this temperature but some radio frequency characteristics may deviate from GSM specification SIM908 Hardware Design_V2 00 9 2012 05 07 Grat Smart Machine Smart Decision Table 2 GPS engine Performance Table 3 Coding schemes on net data rates over air interface A SIM908_Hardware Design_V2 00 10 2012 05 07 ee ee ee A company of SIM Tech 22 Operating Modes
56. rve the restrictions about the use of mobiles Switch the cellular terminal or mobile off medical equipment may be sensitive to not operate normally for RF energy interference Switch off the cellular terminal or mobile before boarding an aircraft Make sure it is switched off The operation of wireless appliances in an aircraft is forbidden to prevent interference with communication systems Forget to think much of these instructions may lead to the flight safety offend against local legal action or both Do not operate the cellular terminal or mobile in the presence of flammable gases or fumes Switch off the cellular terminal when you are near petrol stations fuel depots chemical plants or where 4 blasting operations are in progress Operation of any electrical equipment in potentially explosive atmospheres can constitute a safety hazard Your cellular terminal or mobile receives and transmits radio frequency energy while switched on RF interference can occur if it 15 used close to TV sets radios computers or other electric equipment Road safety comes first Do not use a hand held cellular terminal or mobile when driving a vehicle unless it 15 securely mounted in a holder for hands free operation Before making a call with a hand held terminal or mobile park the vehicle GSM cellular terminals or mobiles operate over radio frequency signals and cellular networks and cannot be guaranteed to connect in
57. s sc is ono WE 45 6 5 VDD EXT WER E Ngo E 45 0 6 SIM VDD Characteristics LAS W E 45 6 7 akc u E Te uuu EE nas ans enn en 45 6 8 Current Consumption VBAT 3 8 V GPS engine is powered down 46 6 9 Electro Static Discharge 011 47 610 Radio Character k u uU Passes passa asusasaanayanqkakusasuyasuyanqkakusasqyasayastyasusasuyasasasukasusssuyasayasukasusas 47 6 10 1 Module NIN Sw EE 47 6 10 2 D n TE EE E eh E 49 6 10 3 Module Operating Frecguenches 49 611 SPADE Iformation 49 51 A Related Documents 51 B Terms and Wl 52 GN EE 53 SIM908 Hardware Design_V2 00 4 2012 05 07 Smart Machine Smart Decision Table Index TABLE 1 SIM908 GSM GPRS ENGINE
58. ser s application pay special attention to power losses Ensure that the input voltage never drops below 3 1 V even when current consumption rises to 2A in the transmit burst If the power voltage drops below 3 1V the module may be shut down automatically The PCB traces from the VBAT pins to the power supply must be wide enough at least 60mil to decrease voltage drops in the transmit burst The power IC and the bypass capacitor should be placed to the module as close as possible VBAT Min 3 1V Figure 10 The minimal VBAT voltage requirement at VBAT drop 4 1 2 Monitoring Power Supply The AT command can be used to monitor the VBAT voltage For detail please refer to document 1 42 Power on down Scenarios 4 2 1 Power on SIM908 4 2 1 1 Turn on SIM908 Using the PWRKEY Pin Power on User can power on SIM908 by pulling down the PWRKEY pin for at least 1 second and release This pin is already pulled up to 3V in the module internal so external pull up is not necessary Reference circuit is shown as below 3V 100 PWRKEY on down logic 4 7K Turn on off impulse 47K MODULE Figure 11 Powered on down module using transistor SIM908_Hardware Design_V2 00 19 2012 05 07 gt 3 E 3 5 209999
59. ta If these pins are unused I2C SCL I O serial bus clock keep open GPIO1 KBRO 31 GPIO1 keypad row 0 GPIO2 KBRI B2 GPIO2 keypad row 1 GPIO3 KBR2 33 GPIO3 keypad row 2 If these pins are unused GPIO4 KBC0 lO _ GPIO4 keypad column 0 SIM card 34 keep open SIM PRESENCE detection GPIOS KBC1 35 GPIOS keypad column 1 GPIO6 K BC2 36 GPIO6 keypad column 3 I Receive data TXD 71 Transmit data If only TXD and RTS 66 O Request to send are used it is suggested CTS 67 I Clear to send to pull down DTR and DCD 70 O Data carrier detect others pins can be kept RI 69 O Ring indicator E DTR I Data terminal ready GPS DBG TXD 15 O For GPS NMEA information output If these pins are unused GPS DBG RXD 16 I debugging and upgrading firmware keep open Voltage supply for SIM card Support SIM VDD 20 O 1 8V SIM card All signals of SIM interface should SIM DATA 17 SIM data input output protected against ESD SIM CLK 19 O SIM clock Patina TVS e SIM RST 18 SIM reset ADC I Input voltage range 2 8V If it is unused keep open PWMI PWM If these pins are unused PWM2 49 PWM keep open PWM3 PWM Impendence must be controlled to 50Q GSM ANT 59 GSM radio antenna connection Impendence must be controlled to 50Q 4 11 12 13 29 30 These pins should 38 39 45 46 53 54 kept open GPS ANT 79 I GPS radio antenna connection NC SIM908_Hardware Design_V2 00 15 2012 05 07
60. tage state The RTC power supply of module can be provided by an external capacitor or a battery non chargeable or rechargeable through the VRTC The following figures show various reference circuits for RTC back up External capacitor for RTC Large capacitance Capacitor SIM908_Hardware Design_V2 00 27 2012 05 07 gt 5 3 E m E Be ecce 5 5 8 Smart Machine Smart Decision Figure 17 RTC supply from capacitor Non chargeable battery for RTC Non chargeable Backup Battery Figure 18 RTC supply from non chargeable battery Rechargeable battery for Rechargeable Backup Battery Figure 19 RTC supply from rechargeable battery Coin type rechargeable battery is recommended such as XH414H IV01E from Seiko can be used Typical charge discharge curves for this battery are Shown in the following figure Charge Discharge Characteristics Charge 3 3V 50uA 5hr RT CC CV Discharge 20uA cov 0V CC Voltage V 0 20 40 60 80 100 uAh Figure 20 Seiko XH414H IV01E charge discharge characteristic SIM908_Hardware Design_V2 00 28 2012 05 07 eo of SIM Tech 4 6 Serial Interfaces Smart Machine Smart Decision SIM908 provides two unbalanced asynchronous serial ports One is the serial port and the other is the debug port The module is designed as a DCE D
61. tings The absolute maximum ratings stated in following table are stress ratings under non operating conditions Stresses beyond any of these limits will cause permanent damage to SIM908 Table 20 Absolute maximum ratings Symbol Parameter Min Typ VBAT Power supply voltage SS Input voltage 0 3 Ir Input current ER Output current Max 5 5 Bal 10 10 These parameters are for digital interface pins such as keypad GPIO C UART LCD PWMs and DEBUG 6 2 Recommended Operating Conditions Table 21 Recommended operating conditions Symbol Parameter Min Typ Max VBAT Power supply voltage 9 2 4 0 4 8 Operating temperature 40 T25 85 TsrG Storage temperature 45 90 6 33 Digital Interface Characteristics Table 22 Digital interface characteristics Symbol Parameter Min Typ Max High level input current 10 10 r Low level input current 10 10 Vin High level input voltage 2 4 Vit Low level input voltage 0 4 Vou High level output voltage gu Vor Low level output voltage 0 1 These parameters are for digital interface pins such as keypad GPIO UART LCD PWMs and DEBUG SIM908 Hardware Design V2 00 44 Unit Unit 2012 05 07 Smart Machine Smart Decision gt 8 3 s 64 SIM Card Interface Characteristics Table 23 SIM card interface characteristics 65 VDD EXT Characteristics Table 24 VDD EXT char
62. tronic Characteristics Table 10 Microphone input characteristics Parameter Min Unit Working Voltage 5 2 0 V Working Current 200 500 uA External Microphone Load Resistance 3 22 kO Internal biasing DC Characteristics 25 V SIM908_Hardware Design_V2 00 32 2012 05 07 ee ee Se lt Differential input voltage THD lt 1 at F 1KHz pre amp gain 20 dB PGA gain 14 dB THD lt 5 at F 1KHz pre amp gain 0 dB PGA gain 0 dB Table 11 Audio output characteristics Parameter Normal Output SPK Conditions Min 320 THD 0 1 320 THD 1 Output swing voltage single ended Output swing voltage differential 4 8 SIM Card Interface 4 8 1 SIM Card Application Smart Machine Smart Decision 15 9 mVrms 740 mVrms Unit 91 96 1 1 Vpp 22 Vpp The SIM interface complies with the GSM Phase specification and the new GSM Phase 2 specification for FAST 64 kbps SIM card Both 1 8V and 3 0V SIM card are supported The SIM interface 15 powered from an internal regulator in the module It is recommended to use an ESD protection component such as ST www st com ESDA6V1W5 or ON SEMI www onsemi com SMF05C The pull up resistor 15 on the SIM DATA line is already added in the module internal Note that the SIM peripheral circuit should be close to the SIM card socket The
63. ures Table 1 SIM908 GSM GPRS engine key features Feature Implementation Power supply 3 2 4 8 Typical power consumption in sleep mode is 1 2mA BS PA MFRMS 9 GPS Power saving engine is powered down Charging Supports charging control for Li Ion battery SIM908 Quad band GSM 850 EGSM 900 DCS 1800 PCS 1900 SIM908 Frequency bands can search the 4 frequency bands automatically The frequency bands also be set by AT command For details please refer to SIM908 Hardware Design V2 00 8 2012 05 07 gt o 3 8 m E SO 9999 E 3 8 Transmitting power GPRS connectivity Temperature range Data GPRS CSD USSD SMS FAX SIM interface External antenna Audio features Serial port and debug port Phonebook management SIM application toolkit Real time clock Physical characteristics Firmware upgrade Smart Machine Smart Decision document 1 Compliant to GSM Phase 2 2 Class 4 ZW at GSM 850 and EGSM 900 Class 1 1W at DCS 1800 and PCS 1900 GPRS multi slot class 10 default GPRS multi slot class 8 option Normal operation 30 80 C Restricted operation 40 30 C and 80 85 Storage temperature 45 90 GPRS data downlink transfer max 85 6 kbps GPRS data uplink transfer max 42 8 kbps Coding scheme CS 1 CS 2 CS 3 and CS 4 Integrate the TCP IP protocol Support Packet B

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