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ADS1282: Buffered input using the THS4531A

Reid Dorrance
Prodigy 60 points

Part Number: ADS1282
Other Parts Discussed in Thread: THS4531A, , THS4521, THS4551

Hi,

We are using the ADS1282 and the THS4531A in a Single-Ended Input to Differential Output Amplifier application. Similar to figure 95 of the data sheet of the THS4531a (Outputs connected thru a small series resistor). Despite a RC filter on differential inputs, will the ADS1282 require a buffer or any other external supporting circuitry to change the differential input impedance?

Thanks,
Reid

  • 0
    TI__Mastermind 44770 points

    Hi Reid,

    I believe the THS4531A should be able to drive the ADS1282 directly with any additional buffers, but I haven't seen the THS4531A tested in this way. Are you planning on bypassing the internal PGA of the ADS1282? If you do run into any issues you can always enable the internal PGA in a gain of 1 as long as your input signal is withing the PGA's absolute input range.

    NOTE: There are several TI Designs that use the THS4521 to drive SAR ADC inputs (see http://www.ti.com/product/THS4521/toolssoftware#Reference%20designs), so using either the THS4521 or the lower noise THS4551 should be able to drive the ADS1282 inputs without issues.

    Also, make sure to use high quality C0G/NP0-type capacitors with low voltage coefficients of capacitance to avoid introducing additional distortion into your signal!

    Best regards,
    Chris