ISL54209EVAL1Z AN1406 ISL54209 1-888-INTERSIL ISL54209IRUZ DFN10

User's Manual ® Application Note Description July 14, 2008 AN1406.0 Picture of Evaluation Board (Top View) The ISL54209EVAL1Z

ISL54209EVAL1Z ISL54209EVAL1Z Evaluation Board User's Manual ® Application Note Description July 14, 2008 AN1406 AN1406.0 Picture of Evaluation Board (Top View) The ISL54209EVAL1Z ISL54209EVAL1Z evaluation board is designed to provide a quick and easy method for evaluating the ISL54209 ISL54209 USB/Audio Switch IC. The ISL54209 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 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 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 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 computer 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 ISL54209 device in both the Audio mode and the USB mode. Features · Standard USB Connectors · RCA Audio Input Jacks and Headphone Speaker Jack · Convenient Test Points and Connections for Test Equipment 1 FIGURE 1. ISL54209EVAL1Z 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 32 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. 5. Located in the center of the board is the ISL54209 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. CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures. 1-888-INTERSIL 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 100µA of current. Logic Control The state of the ISL54209 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 VBUS 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 µcontroller. Logic "0" (LOW) when 0.5V or floating Logic "1" (HIGH) when 1.4V Note: The evaluation board has the option of putting a 4M pull-down resistor from the IN pin to ground by putting a jumper at JP4. However it is not required for the ISL54209 ISL54209 part because the IN and CTRL pins have internal 4M 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 VBUS 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 VBUS 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 500k resistor should be put in series with the IN pin if the VBUS voltage is greater than the VDD voltage. This resistor is not on the evaluation board. There is an 2 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 VBUS = 5.25V and VDD = 3.3V, this resistor will limit the current to around 2.76µA 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 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 (0.707Vrms) these switches have an extremely low rON resistance variation. They can pass ground referenced audio signals with very low distortion (