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THS3201 / use for transimpedance amp

Toshiyuki
Mastermind 7075 points
Other Parts Discussed in Thread: THS3201

Hi,

Customer is choosing THS3201 for avalanche photodiode transimpedance amp.

However, I believe almost all transimpedance amps are voltage-feedback, not current-feedback.

Could we use THS3201 as a transimpedance amp ?

Best Regards,

Kato

  • 0
    TI__Genius 12631 points

    Hello,

     Current Feedback amps do have some inherent issues with their use as transimpedance amps:

    1. DC bias current at the inverting node is higher than a lot of VFAs

    2. Inverting current noise is higher than VFAs.

    3. The BW of CFAs depend on the value of the feedback resistance, so large values of transimpedance gain can kill the BW. Furthermore, stabilizing TIAs may require a feedback capacitance to shape the noise gain - CFAs tend to have stability issues with feedback caps. This being said if you are knowledgable about how to properly shape the noise gain you can get by with stabilizing a CFA in a TIA application.

    -Samir