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OPA2140: input current noise

Renan Santos Adriano
Genius 16530 points
Part Number: OPA2140

Hello Team,

My Customer is using the OPA2140 as a positive amplifier for low noise DC source. They do not found any information about input current noise in the datasheet. They did some tests and found out that the noise depends dramatically on the voltage at the input pins and in temperature. They are asking for more information about the input current noise for a better design of a lower noise amplifier.

Do we have such a document we can share with them?

Regards,

Renan

  • 0
    Guru 47515 points

    Well Renan, 

    These JFET input devices really only have a leakage input bias current, from that max 10pA number, you can solve for the max input current noise through root(2qIdc) or 1.8fA/rootHz - usually not an issue in most designs unless you are using high impedances. 

  • 0
    TI__Genius 10850 points

    HI Ranan,

    Michael is correct. Please let us know if you have any additional questions. The engineer responsible for this family of devices is out of office on Holiday, so responses may be a bit delayed.