PCF8570P/F5,112 datasheet by NXP Semiconductors

PCF8570P/F5,112 Frequently Asked Questions (FAQs)

• What is the maximum frequency of the I2C bus that the PCF8570 can handle?
  The PCF8570 can handle I2C bus frequencies up to 400 kHz, but it's recommended to use a maximum frequency of 100 kHz for reliable operation.
• Can I use the PCF8570 as a level shifter between 3.3V and 5V systems?
  Yes, the PCF8570 can be used as a level shifter between 3.3V and 5V systems, but it's essential to ensure that the input voltage (VCC) is within the recommended range (2.5V to 6.0V) and that the output voltage (VOUT) is within the specified range for the specific application.
• How do I handle the internal pull-up resistors on the PCF8570?
  The internal pull-up resistors on the PCF8570 are enabled by default. To disable them, you need to write a '0' to the corresponding register bit. It's recommended to disable the internal pull-up resistors if you're using external pull-up resistors or if you're connecting the PCF8570 to a bus with existing pull-up resistors.
• What is the maximum current that the PCF8570 can sink or source?
  The PCF8570 can sink or source up to 25 mA per output pin, but the total current should not exceed 100 mA for the entire device.
• Can I use the PCF8570 as an output expander with a microcontroller that has limited GPIO pins?
  Yes, the PCF8570 is commonly used as an output expander to increase the number of GPIO pins available on a microcontroller. It can be used to control LEDs, relays, or other devices that require a digital output signal.