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TXB0302: Usage this part in DMIC function has noise occurred.

Kyle Chang27
Prodigy 135 points
Part Number: TXB0302
Other Parts Discussed in Thread: 2N7001T, SN74AXC1T45, SN74AVC2T45

Dear TI,

Does this level shift can able to use in DMIC function?

BR

Kyle.

  • 0
    TI__Guru 62080 points

    Kyle,

    If you could highlight some key specs related to DMIC, it would be helpful.

    Translation requirements, speed/datarate, open drain or push pull, unidirectional or bidirectional signal etc will be helpful.

  • 0 in reply to ShreyasRao
    Prodigy 135 points

    Dear Shreyas,

    1. DMIC signal from Intel Kabylake U.

    2.the voltage level need to raise from 1.8V to 3.3V.

    3.the clk frequency is 2.4 MHz.

    4.the raising and falling time maximum is 13 ns.

    Do you have any suggest about this? like circuit, CL ,,,

    attach the DMIC sensor spec.

  • 0 in reply to Kyle Chang27
    TI__Guru 62080 points
    Dear Kyle,

    TXB0302 (auto bidirectional ) will support all the requirements as listed for the DMIC signal.
    There is also 2N7001T(unidirectional) or SN74AXC1T45 (DIR controlled translation) device we recently released which can support 1.8V <->3.3V and exceeding all other requirements listed here.
  • 0 in reply to ShreyasRao
    Prodigy 135 points

    Thank you~
    But I have a issue that as title..
    I think this part can do this.
    But I can't rationalize the waveform that I measured.

    Ch1 is before.
    Ch2 is after.
    Do you know this symptom root cause is what?

    Attach the schematic.

    Best,

    Kyle.

  • 0 in reply to Kyle Chang27
    TI__Guru 62080 points
    Kyle,

    It seems that the device is loaded on the IO ports which is why the output signal is not achieving the desired 3.3V level.
    The TXB0302 is trying to reach the 3.3V final level if you track the high signal(its still rising and not reached the final level). do you have additional loading on the traces not shown here?
    how is it being measured on the scope and what is the probe capacitance? having an active probe with low cap load will help.

    I would recommend using the DIR controlled device, either the SN74AXC1T45 or the SN74AVC2T45 which can work well here.