PCF8574PWRE4 datasheet by Texas Instruments

PCF8574PWRE4 Frequently Asked Questions (FAQs)

• What is the maximum frequency of the I2C bus that the PCF8574PWRE4 can support?
  The PCF8574PWRE4 can support I2C bus frequencies up to 400 kHz, but it is recommended to operate at 100 kHz or lower for reliable operation.
• Can the PCF8574PWRE4 be used as a level shifter for 5V to 3.3V or vice versa?
  Yes, the PCF8574PWRE4 can be used as a level shifter for 5V to 3.3V or vice versa, but it is not recommended as it is not designed for level shifting and may not provide reliable operation.
• What is the maximum current that can be sourced or sunk by the PCF8574PWRE4?
  The PCF8574PWRE4 can source or sink up to 25 mA of current per pin, but it is recommended to limit the current to 10 mA or less to ensure reliable operation.
• Can the PCF8574PWRE4 be used in a 5V system with 5V logic levels?
  Yes, the PCF8574PWRE4 can be used in a 5V system with 5V logic levels, but it requires an external voltage regulator to regulate the VCC pin to 3.3V or lower.
• What is the purpose of the internal pull-up resistors on the PCF8574PWRE4?
  The internal pull-up resistors on the PCF8574PWRE4 are used to pull up the I2C bus lines (SCL and SDA) to the VCC voltage when the device is not actively driving the bus.