PCF8574RGTR datasheet by Texas Instruments

PCF8574RGTR Frequently Asked Questions (FAQs)

• What is the maximum frequency of the I2C bus that the PCF8574RGTR can support?
  The PCF8574RGTR can support I2C bus frequencies up to 400 kHz, but it's recommended to operate at 100 kHz for reliable operation.
• How do I handle the internal pull-up resistors on the I2C bus?
  The internal pull-up resistors on the I2C bus are enabled by default. To disable them, connect an external pull-up resistor to the SCL and SDA lines. The recommended value is 2.2 kΩ for 100 kHz operation.
• What is the maximum current that the PCF8574RGTR can sink or source on each I/O pin?
  The PCF8574RGTR can sink or source up to 25 mA on each I/O pin, but it's recommended to limit the current to 10 mA to ensure reliable operation.
• How do I reset the PCF8574RGTR?
  The PCF8574RGTR can be reset by pulling the RESET pin low for at least 1 ms. This will reset the device to its default state.
• Can I use the PCF8574RGTR as a level shifter?
  Yes, the PCF8574RGTR can be used as a level shifter between 3.3 V and 5 V logic levels. However, it's recommended to use an external voltage regulator to ensure stable operation.