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ADS127L01: Is there a buffered single ended to differential driver available?

Ed Marquette1
Prodigy 10 points
Part Number: ADS127L01
Other Parts Discussed in Thread: THS4551, , OPA320

We're using the ADS127L01 with a multiplexer.  If we use the normal differential in, differential out adc driver like the THS4551 then I need a buffer between the mux and THS4551 so the on resistance of the mux doesn't affect signal level, so more space, cost, and noise is involved.  Is there a way to drive the ADS127L01 using just a single part?  Thanks

  • 0
    TI__Mastermind 40610 points

    Hello Ed,

    I am not aware of a single device solution.  For best performance, adding a buffer in front of the FDA stage will give the best overall performance.  The EVM board has a spot to include such a buffer.  If your input range is less than 5V, you could use an OPA320 or similar amplifier as the buffer.  For +/-12V signals, the OPA192 would be a good option.

    If you do not need the absolute best THD performance, you could use a dual op-amp for a single ended to differential driver.  The below cookbook circuit shows the basic topology.

    http://www.ti.com/lit/an/sbaa265/sbaa265.pdf

    This circuit uses the OPA320 to drive an 18b, 1MSPS SAR data converter.  For the ADS127L01, you will likely need a higher bandwidth amplifier.  The OPA2625 would be a good choice.  You will likely need to adjust the input RC filter values; I would start with the EVM values of 10ohm and 22nF.

    Regards,

    Keith N.
    Precision ADC Applications