PCF8574ADWG4 datasheet by Texas Instruments

PCF8574ADWG4 Frequently Asked Questions (FAQs)

• What is the maximum frequency of the I2C bus that the PCF8574ADWG4 can support?
  The PCF8574ADWG4 can support I2C bus frequencies up to 400 kHz, but it is recommended to operate at 100 kHz or lower for reliable operation.
• How do I handle the internal pull-up resistors on the I2C bus?
  The PCF8574ADWG4 has internal pull-up resistors on the I2C bus, but they are not enabled by default. You need to enable them by setting the PU (Pull-up Enable) bit in the Control Register (CR) to 1.
• What is the maximum current that can be sourced or sunk by the PCF8574ADWG4's I/O pins?
  The PCF8574ADWG4's I/O pins can source or sink up to 20 mA of current, but it is recommended to limit the current to 10 mA or less to ensure reliable operation.
• How do I reset the PCF8574ADWG4?
  The PCF8574ADWG4 can be reset by pulling the RESET pin low for at least 1 ms. This will reset the device to its default state and clear all registers.
• Can I use the PCF8574ADWG4 as a level translator?
  Yes, the PCF8574ADWG4 can be used as a level translator between 5V and 3.3V or 2.5V systems. However, it is recommended to use an external voltage regulator to ensure that the VCC pin is at the correct voltage level.