SBOU260 September   2021 ISOUSB111

 

  1.   Trademarks
  2. 1Introduction
  3. 2Overview
  4. 3Pin Configuration of the ISOUSB111 Full/Low Speed Isolated USB Repeater
  5. 4EVM Setup and Operation
  6. 5EVM Schematics
  7. 6PCB Layout and 3D Diagram
  8. 7Bill of Materials

4 EVM Setup and Operation

This section describes the typical setup and operation of the EVM for device evaluation. Figure 4-1 shows a typical test configuration for operating the ISOUSB111DWEVM using an USB 2.0 type-B receptacle.

Figure 4-1 Typical EVM Test Setup
Use a jumper to connect pin 2 to pin 1 of J10 to enable the U3 LDO. The U3 LDO provides a 5 V supply to the USB device, and it also powers the U5 LDO to generate 3.3V. If an external 5V source is used to power the USB device through TP5, connect pin 2 to pin 3 of J10 to disable the U3 LDO and set its output to high impedance.

ISOUSB111DWEVM has many DNP resistors which can be populated or unpopulated to setup the EVM to desired operating test conditions. Table 4-1 lists and describes all the possible test configurations that can be achieved by populating various resistors.

Table 4-1 Resistor Configurations
Resistor Description
R7 DNP is the default. To disable the U4 LDO, populate a zero ohm resistor on R7 and not populate R8.
R8 Connects U4 E N - to ground to enable the LDO. When R8 is populated, R7 needs to be unpopulated.
R9 Connects VBUS1 to type-B receptacle VBUS. VBUS1 is power at 5 V when R9 is populated. When R9 is populated, R10 and R11 need to be unpopulated to disconnect the U4 LDO to VBUS1 and V3P3V1 pins. The internal LDO of ISOUSB111 will generate 3.3 V for V3P3V1 pin.
R10, R11 DNP is the default. Populating R10 and R11 connects the U4 LDO to VBUS1 and V3P3V1 pins. When these two resistors are populated, R9 need to be unpopulated. When R10 and R11 are populated, VBUS1 and V3P3V1 are set to 3.3 V.
R12 DNP is the default. To disable the U5 LDO, populate a zero ohm resistor on R12 and not populate R13.
R13 Connects U5 E N - to ground to enable the LDO. When R8 is populated, R7 needs to be unpopulated.
R14 DNP is the default. It connects VBUS2 to the output of U3 LDO. VBUS2 is power at 5V when R14 is populated. R15 and R16 need to be unpopulated to disconnect the U5 LDO to VBUS2 and V3P3V2 pins. The internal LDO of ISOUSB111 will generate 3.3 V for V3P3V2 pin.
R15, R16 Populating R15 and R16 connects the U5 LDO to VBUS2 and V3P3V2 pins. When these two resistors are populated, R14 need to be unpopulated. When R15 and R16 are populated, VBUS2 and V3P3V2 are set to 3.3 V.
R17, R18, R19, R20 For internal debug purposes.