• Resolved

ultra low power instrumentation amplifier

Prodigy 120 points

Replies: 15

Views: 265

Hi 

How to design ~2uA current low speed instrumentation amplifier using 3 op amp schematic (https://en.wikipedia.org/wiki/Instrumentation_amplifier) ?

Now in-amp current depends on feedback resistors values. 

How big resistors values can be selected to have lowest current and stable in-amp performance?

 

  • In reply to Thomas Kuehl:

    So we can decrease current to 1uA of R7/R8 divider.  i understand the answer  is yes?

    And some small capacitor will help to lower noises.

    Instrumental amplifier with TLV8812  works fine. We tested.

    Now we will try to use TLV8812 for potentiostat circuit. I will inform the results. 

    Vaidas

  • In reply to Vaidas Serpetauskas:

    Hello Vaidis,

    It is good hear the TLV8812 is working well meeting the very low operating current INA portion of the application. It should work well in the potentiostat application as well. The very low +/-100 fA input (typ) bias current is ideal for that application.

    Please do let us know the results you receive from the TLV8812 for the complete application.

    Regards, Thomas

    Precision Amplifiers Applications Engineering

  • In reply to Thomas Kuehl:

    Also keep in mind if your desire is only 1Hz, you are now in the 1/f noise region, up to 500nV at 1Hz with the TLV8811. Maybe should run an output SNR for the whole thing, 

    There was an earlier file using the LPV821 showing 2Vpp, that is 0.707Vrms for the SNR simulation. Might try something like this with your current circuit. 

    Michael Steffes

  • In reply to Vaidas Serpetauskas:

    Hi Vaidas,

    If you have the information you need for now and could close this e2e inquiry it would be helpful to us who support the Precision Amplifiers forum. If you need to reopen the discussion a new e2e inquiry can be started at any time.

    Thanks, Thomas

    Precision Amplifiers Applications Engineering

  • In reply to Thomas Kuehl:

    ok

    Thanks