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TI TCA4311A and NXP PCM9510AD

kerr chang
Genius 4075 points

Other Parts Discussed in Thread: TCA4311A

HI Team

         we want use TI TAC4311A to replace NXP PCM9510.

The PCM9510 does not have rise time boost circuitry but the TI component does.  The significance is that there could be interference with other switches or buffers that are connected on the same bus.   This warning is mentioned in the PCM9510 data sheet.

Could yor let me know what rise time boost circuitry is ?

  • 0
    TI__Genius 16560 points
    Kerr Chang,

    You are correct. Rise time accelerators are not recommended for use with buffers or other rise time accelerators on the same bus. The reason for this is that ringing/false edges can be created as a result. For this reason, I would not recommend replacing the PCM9510 with the TCA4311A, as you may introduce some communication issues if they have other buffers on the same bus. Unfortunately, we do not currently have a version of this device without rise time accelerators.


    Rise time accelerators are current sources that get turned on for a very short period of time (~30 ns typically). When the device detects that the bus is getting pulled up by the resistor, it will engage the rise time accelerator, which is a high current source, to pull the bus high quickly. Then it turns off.

    The issue with this is on long cable runs through buffers, there is propagation delay, which may allow the signal to rise up slightly during a hand off (such as the acknowledge pulse) of the SDA line, and this could trip the rise time accelerator, causing a false data or clock edge.