PCA9539PWE4 datasheet by Texas Instruments

PCA9539PWE4 Frequently Asked Questions (FAQs)

• What is the maximum frequency of the I2C bus that the PCA9539PWE4 can support?
  The PCA9539PWE4 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 case where the PCA9539PWE4 is not responding to I2C commands?
  If the PCA9539PWE4 is not responding to I2C commands, try resetting the device by toggling the RESET pin low and then high. Also, check the I2C bus for any bus contention or noise issues.
• Can I use the PCA9539PWE4 to drive inductive loads such as relays or solenoids?
  No, the PCA9539PWE4 is not designed to drive inductive loads such as relays or solenoids. It is recommended to use an external driver or buffer to drive such loads.
• How do I determine the correct pull-up resistor value for the I2C bus?
  The correct pull-up resistor value for the I2C bus depends on the bus capacitance, frequency, and voltage. A good starting point is to use a 2.2 kΩ pull-up resistor for a 100 kHz I2C bus, but you may need to adjust the value based on your specific application.
• Can I use the PCA9539PWE4 to read the state of an input pin?
  Yes, the PCA9539PWE4 can be used to read the state of an input pin. The device has an input port that can be read through the I2C interface.