Application Note
Contents
1. 5 Located in the center of the board is the ISL54209 IC U1 The evaluation board has a pin 1 dot to show how the IC should be oriented onto the evaluation board The IC pin 1 indicator dot needs to be aligned with the evaluation board pin 1 dot indicator 1 CAUTION These devices are sensitive to electrostatic discharge follow proper IC Handling Procedures 1 888 INTERSIL or 1 888 468 3774 Intersil and design is a registered trademark of Intersil Americas Inc Copyright Intersil Americas Inc 2008 All Rights Reserved All other trademarks mentioned are the property of their respective owners Application Note 1406 Power Supply The DC power supply connected at banana jacks J10 VDD and J11 GND provides power to the part The IC requires a 2 7V to 5 5V DC power supply for proper operation The power supply should be capable of delivering 100UA of current Logic Control The state of the ISL54209 device is determined by the voltage at the IN pin and the CTRL pin Access to the CTRL pin is through the banana jack J12 CTRL Access to the IN pin is through banana jack J13 IN when jumper JP3 is in position 2 to 3 and through the USB J1 USB TO HOST connector Vguys line when the jumper JP3 is in position 2 to 1 The following control pins are 1 8V logic compatible which allows for control via a standard pcontroller Logic 0 LOW when lt 0 5V or floating Logic 1 HIGH when gt 1 4V Note The e2. SETUP BLOCK DIAGRAM Using The Board Refer to Figure 2 Lab Equipment The equipment external supplies and signal sources needed to operate the board are listed below 1 3V to 5V dc Power Supply 2 Stereo Audio Source MP3 Radio CD Player or Audio Generator Headphone Set or Audio Analyzer Oscilloscope Two Standard USB Cables Computer with USB Port USB Device i e USB Memory Stick MP3 Player with USB Port etc oon fk Ww Initial Board Setup Procedure 1 Attach the main evaluation board to a DC power supply at J10 VDD and J11 GND Positive terminal at J10 and negative terminal at J11 The supply should be capable of delivering 3V to 5V and 100mA of current Set the supply voltage to 3 3V 2 Connect the stereo audio source left channel to J3 RCA connector or J5 BNC connector and right channel to J4 RCA connector or J6 BNC connector 3 Connect the USB device to the USB B type receptacle J2 USB TO DEVICE Audio Mode Operation 1 Install headphone in the headphone jack J7 No USB cable should be connected at the J1 USB TO HOST connector Logic Control Put CTRL Logic 1 and IN Logic 0 You will now be in Audio mode 3Q audio switches are ON Turn the audio source ON You should hear the music in the headphones You can observe the audio signals at the output of the IC on an oscilloscope or audio analyzer by using the J8 and J9 BNC connectors C
3. the D line of the J1 USB connector The BNC connector J14 D is in parallel with the D line of the J2 USB connector The BNC connector J15 D is in parallel with the D line of the J2 USB connector If you want to use the J14 and J15 BNC connectors you must populate R4 and Ro with OQ resistors These BNC connectors can be used to connect test equipment to evaluate the performance of the IC BOARD COMPONENT DEFINITIONS DESIGNATOR DESCRIPTION U1 ISL54209IRUZ IC J1 B type USB Receptacle J2 A type USB Receptacle J3 J5 Left Stereo Audio Input J4 J6 Right Stereo Audio Input J7 Headphone Speaker Jack J8 COM BNC Connector J9 COM BNC Connector J10 VDD Positive Connection J11 VDD GND Connection J12 CTRL Logic Control J13 IN Logic Control J14 D BNC Connector J15 D BNC Connector JP1 JP2 D D Differential Probe Connection JP3 IN Pin Connector Selection Jumper Position 2 to 3 Control through J13 Jumper Position 2 to 1 Control through J1 JP4 Connect 4MQ Pull down Resistor to IN Pin 3 intersil July 14 2008 Application Note 1406 COMPUTER USB PORT USB TO HOST JP2 HEADPHONE JACK O COM COM JP3 U1 iy ele ISL54209EVAL1Z EVALUATION BOARD LOGIC CONTROL USB DEVICE CTRL 0 J12 USB DEVICE J2 sO AUDIO LEFT AUDIO RIGHT FIGURE 2 BASIC EVALUATION TEST
4. 6mW into a 32Q headphone speaker load A 3Vp p signal is acceptable but performance will degrade The audio input channels are AC coupled with 100uF capacitors These capacitors remove any DC voltage from the audio signals and reference them to ground of the device If the audio source being connected to the evaluation board already has internal AC coupling capacitors at the output of its drivers then the capacitors on the evaluation board should be shorted out replaced with OQ resistors This will prevent further attenuation of the low frequency content of the audio signal due to the increase of the high pass corner frequency resulting from the evaluation board capacitor in series with the audio source capacitor Audio Outputs The evaluation board has a standard headphone jack labeled HEADPHONE JACK J7 A 32Q stereo headphone should be plugged into this jack The BNC connector J8 COM is in parallel with the audio left line of the headphone jack and the D line of the J1 USB To HOST connector The BNC connector J9 COM is in parallel with the audio right line of the headphone jack and the D line of the J1 USB To DEVICE connector These BNC connectors can be used to connect resistive loads and or test equipment to evaluate the performance of the IC 2 intersil July 14 2008 Application Note 1406 USB Connections A B type USB receptacle labeled USB TO HOST J1 is located on the left under side of
5. eater than the VDD voltage This resistor is not on the evaluation board There is an internal diode in the IC from the IN pin to VDD that will get forward biased and draw current as the voltage at the IN pin exceeds the VDD voltage With Vays 5 25V and VDD 3 3V this resistor will limit the current to around 2 76uA and the voltage at the IN pin will be around 3 6V which is well above the VinH minimum level of 1 4V required for proper operation When the computer is not connected at J1 the internal pull down will pull the IN pin low putting the ISL54209 in the Audio mode or Low Power mode depending on the condition of the CTRL pin When a USB cable from the computer is connected at J1 the voltage at the IN pin will be driven high and the part will automatically go into the USB mode Audio Inputs The evaluation board has two audio inputs labeled AUDIO LEFT J3 or J5 and AUDIO RIGHT J4 or J6 Each of these inputs have a BNC connector wired in parallel with a RCA jack connector You can connect an audio source generator at either the BNC connector or the RCA connector In a typical application the left and right outputs of a stereo source such as an MP3 player would be connected to the RCA jacks J3 and J4 respectfully Over a signal range of 1V 0 707V ms these switches have an extremely low ron resistance variation They can pass ground referenced audio signals with very low distortion lt 0 05 THD N when delivering 15
6. er to the USB connector J1 USB TO HOST This will establish a connection from the computer through the USB switches of the IC to the USB device connected at the USB connector J2 USB TO DEVICE to send and receive data This application note will guide the user through the process of configuring and using the evaluation board to evaluate the ISL54209 device in both the Audio mode and the USB mode Features Standard USB Connectors e RCA Audio Input Jacks and Headphone Speaker Jack Convenient Test Points and Connections for Test Equipment ISL54209EVAL1Z Evaluation Board User s Manual AN1406 0 July 14 2008 Picture of Evaluation Board Top View FIGURE 1 ISL54209EVAL1Z EVALUATION BOARD Board Architecture Layout Basic Layout of Evaluation Board The basic layout of the main board is as follows Refer to Figure 1 1 Power and Ground connections are at the top of the board J10 and J11 2 Logic control connections are at the top of the board J12 and J13 3 Audio Source Inputs are at the lower right side of the board J3 J6 Audio outputs are at the lower left side of the board J7 J8 J9 Connector J7 is a standard headphone jack for connecting a 329 headphone 4 USB connection to an upstream host controller Computer is made at connector J1 located on left under side of the board USB connection to a downstream USB device is made at connector J2 located on right underside of the board
7. intersil Application Note Description The ISL54209EVAL1Z evaluation board is designed to provide a quick and easy method for evaluating the ISL54209 USB Audio Switch IC The ISL54209 device is an unique IC To use this evaluation board properly requires a thorough knowledge of the operation of the IC Refer to the data sheet for an understanding of the functions and features of the device Studying the device s truth table along with its pinout diagram on page 2 of the ISL54209 data sheet is the best way to get a quick understanding of how the part works A picture of the main evaluation board is shown in Figure 1 The ISL54209 TDFN IC is soldered onto the evaluation board It is located in the center of the board and is designated as U1 The ISL54209 IC has two modes of operation called Audio mode and USB mode The evaluation board contains standard Audio and USB connectors to allow the user to easily interface with the IC to evaluate its functions features and performance in the two modes of operation For example when the board is properly powered a headphone can be plugged into the headphone jack J7 and a stereo source such as a MP3 player can be connected at the RCA connectors J3 AUDIO LEFT and J4 AUDIO RIGHT to play music through the audio switches of the IC Figure 2 You can then turn off the audio source remove the headphones configure the logic for USB operation and then attach a USB cable from a comput
8. onnect to J8 for Left audio and J9 for right audio USB Mode Operation 1 2 3 Turn OFF audio stereo source Remove headphone from J7 Headphone Jack Logic Control Put CTRL Logic X and IN Logic 1 You will now be in USB mode 5Q USB switches are ON Connect USB cable from computer USB port to the USB A type receptacle J1 USB TO HOST on the evaluation board The computer should indicate that it is connected to the USB device connected at the J2 connector You will now be able to send and receive data between the computer and USB device You can observe the D and D USB digital signals on an oscilloscope or other test equipment by connecting to the J8 J14 J9 and J15 BNC connectors or various test points located on the board See Test Points on page 5 4 intersil July 14 2008 Application Note 1406 7 Remove the 09 resistors Ry R2 Rg R4 when evaluating Test Points the performance i e eye diagram etc of the high speed USB signal Removal of these resistors disconnects the A k The test t lable are headphone jack J7 and BNC connectors J8 J9 J14 E aa S AE J15 from the USB differential lines These components when connected will degrade the USB signal These TABLE 1 The board has various test points for connecting probes to i re in an lication components will not be there in an actual applicatio DESIGNATOR DESCRIPTION If y
9. ou disconnect the USB cable from J1 and take the IN pin TP1 Vpp Test Point LOW the IC will return to Audio mode You can now plug the headphone set into headphone jack turn the audio source TP2 Ground Test Point ON to once again play music TP3 Veus Test Point TP4 Audio Left Input Test Point TP5 Audio Right Input Test Point JP1 D D Differential Probe Connection USB Device Side of Switch JP2 D D Differential Probe Connection COM Side of Switch 5 i i Intersil July 14 2008 Application Note 1406 Board Schematic AUDIO LEFT AUDIO RIGHT a CTRL MOUNT 4 6 J2 MOUNT sy J3 N eA J4 J12 g D eA gt Er mk senvk ale p h p u K aNd N q 1 wa oe n ra ma l q2 g ome Op aO lo lt amp a e N p ZO a FO 5 N3dO 2 m 0 so lt ma eLLaN p OTST 2cn Oe a a pas a a 2 S a RO KA z ZU als S o T2 U US 5 lt gt S S Wx t lt 7 p zo od Q Q a on I oO S noo Q DETI Q q wi I Intersil Corporation reserves the right to make changes in circuit design software and or specifications at any time without notice Accordingly the reader is cautioned to verify that the Application Note or Technical Brief is current before proceeding For information regarding Intersil Corporation and its products see www intersil com 6 i i Intersil July 14 2008
10. the board This receptacle should be connected using a standard USB cable to the upstream USB host controller which is usually a PC computer or hub When this connection is made and the IN logic control is driven HIGH the ISL54209 device will go into USB mode The USB switches will be turned ON An A type USB receptacle labeled USB TO DEVICE J2 is located on the right underside of the board The USB device can be plugged directly into this receptacle or through a standard USB cable In USB mode the USB host controller and USB device will be connected through the internal USB switches of the IC The USB switches are bi directional which allow the host computer and downstream USB device to both send and receive data Note Before connecting the USB host controller at connector J1 the headphones must be removed from the headphone speaker jack J7 This will prevent the audio load from interfering with USB signal transmission The main purpose of the ISL54209 device is to allow the use of a common USB and Audio Headphone Connector in Personal Media Players and other portable battery powered equipment Either a headphone will be in the common connector to play music or a USB cable from a computer will be in the common connector to transmit digital data ie MP3 into the memory of the Media Player The BNC connector J8 COM is in parallel with the D line of the J1 USB connector The BNC connector J9 COM is in parallel with
11. valuation board has the option of putting a 4MQ pull down resistor from the IN pin to ground by putting a jumper at JP4 However it is not required for the ISL54209 part because the IN and CTRL pins have internal 4MQ pull down resistor These resistors pull the logic pins to ground when J13 J1 or J12 are floated If IN is driven LOW and CTRL is HIGH the part will be in the Audio mode The audio switches will be ON and the USB switches will be OFF If IN is driven HIGH and CTRL X don t care the part will be in the USB mode The USB switches will be ON and the audio switches will be OFF If IN is LOW and CTRL LOW the part will be in the Low Power mode In Low Power mode all switches are OPEN and the part will draw around 1nA of current SETTING UP THE EVALUATION BOARD TO USE THE COMPUTER Veus VOLTAGE TO DRIVE THE IN PIN Rather than using a logic controller to control the IN logic pin through the J13 IN banana jack you can directly drive the IN pin using the Vays voltage from the computer through the USB J1 USB TO HOST connector To control the part through the J1 connector make the following connections 1 Install jumper JP3 at location 2 to 1 This connects the Vbus line of the J1 USB connector to the IN pin of the part Note With the jumper in this position the J13 banana jack is no longer connected to the IN pin of the part 2 A 500kQ resistor should be put in series with the IN pin if the Vgus voltage is gr
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