PCF8574DWRG4 datasheet by Texas Instruments

PCF8574DWRG4 Frequently Asked Questions (FAQs)

• What is the maximum frequency of the I2C bus that the PCF8574 can handle?
  The PCF8574 can handle I2C bus frequencies up to 400 kHz, but it's recommended to limit it to 100 kHz for reliable operation.
• Can I use the PCF8574 as a level shifter between 3.3V and 5V systems?
  Yes, the PCF8574 can be used as a level shifter between 3.3V and 5V systems, but make sure to follow the recommended voltage levels and current limitations.
• How do I handle the internal pull-up resistors on the I2C bus?
  The internal pull-up resistors on the I2C bus are typically around 10 kΩ. You can add external pull-up resistors if needed, but make sure to calculate the total resistance to avoid overloading the bus.
• What is the maximum current that can be sourced or sunk by the PCF8574's I/O pins?
  The maximum current that can be sourced or sunk by the PCF8574's I/O pins is around 25 mA per pin, but it's recommended to limit it to 10 mA per pin for reliable operation.
• Can I use the PCF8574 to drive inductive loads like relays or solenoids?
  No, the PCF8574 is not designed to drive inductive loads like relays or solenoids. It's recommended to use an external driver or buffer for such applications.