SCPA062 July   2021 TCA9517

 

  1.   Trademarks
  2. 1Introduction
  3. 2SDA Signal During Acknowledge
  4. 3SDA Signal During Acknowledge With Propagation Delay (TCA9517 A to B)
    1. 3.1 Example Waveform in Actual System
  5. 4System Impact
  6. 5SDA Handoff Delay After the Acknowledge
  7. 6Concern With Rise Time Accelerators
  8. 7Conclusion

7 Conclusion

By adding a device with buffers to the I2C communication path, propagation delay is added to the signal transmission. The propagation delay can result in a small window of time where the controller has released the bus to allow for target to Acknowledgment, while the target has not yet taken control of the bus to send the Acknowledge. The impact of this is potentially a voltage spike on the SDA line of the controller, which is non-consequential to a traditional system. The consequence of this is impactful if there is a rise time accelerator on the I2C bus which may cause potential damage to the devices driving the bus if the rise time accelerators were to turn on due to the voltage spike during this window.