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OPA2192: opa2192 replace LT6011IS8 issue

user3830479
Expert 1090 points
Part Number: OPA2192
Other Parts Discussed in Thread: OPA192, OPA189, OPA188

Dear all；

    We uesd OPA2192 replace LT6011IS8, The performance of OPA2192 is better than LT6011, but the OPA2192 output signal noise is greater than LT6011，

 Can you give suggestions for improvement or have more suitable partnumber recommendations. so2-1 is waveform for LT6011. Attached is circuit, thanks!0702.Circuit.pdf

  • 0
    TI__Guru* 93105 points

    Hello user3830479,

    Your potentiostat application it is best served by an op amp having both very low input bias current and low 1/f (0.1 to 10 Hz) noise. TI has a number of low 1/f precision op amps, but because of the very low input bias current requirement or their input common-mode input voltage (VCM) limits with +6 Vs and +2.5 Vmid, they don't quite fulfill the application needs. Therefore, I don't have a recommended replacement for the OPA2192.

    If I find something I haven't considered that meets the applications requirements, I'll let you know.

    Regards, Thomas

    Precision Amplifiers Applications Engineering

  • 0
    TI__Guru 67601 points

    I do not see  so2-1 node on your schematic and you show multiple circuits using LT6011.  Having said that, total noise is a function of bandwidth and OPA192 has much higer bandwidth than LT6011, 10MHz vs 350kHz, respectively, which with everything else equal will result in a higher noise.  Also, if you are looking at one of the high-gain circuits, its noise bandwidth is very low, BW=GBW/Gain, and therefore the low frequency, 1/f, noise dominates the total noise.  

    If you compare 1/f noise of LT6011 and OPA192, the former actually has lower noise - see below, and thus it is no surprise that its total noise is lower.

    Therefore, you may want to consider using one of our zero-drift amplifier like OPA188 or OPA189, which have no 1/f noise.

  • 0 in reply to Marek Lis
    TI__Genius 11135 points
    Hello user3830479

    We haven't heard back from you so we assume this answered your question. If you need additional help just post another reply.

    Thanks
    Dennis