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INA configuration using OPA3695

Cristina Oliveira
Prodigy 20 points
Other Parts Discussed in Thread: OPA3695

Hi!

I need high speed amplifiers with high slew rate in order to amplify a differential signal coming from sensors. In the end I need a single signal so I figured the best option is to use the OPA3695 since it has very high slew rate and the IC comes with the 3 amps which makes it ease to implement the instrumentation amplifier configuration. A have a transformer prior to the inputs of the amplifier to avoid low frequency noise, and I'll be using a +/-1.75V voltage supply to limit my output to ~ +/- 0.8V.

I don't need a very high gain, around +2V/V to +4 V/V would be fine, my question is what are the best recommended feedback resistors for such a low voltage supply.

Thanks.

Cristina Oliveira

  • 0
    TI__Expert 4115 points

    Cristina,

    I would recommend to operate the OPA3965 with +/-2.5V (total 5V) power supply and use recommended values shown in data sheet for +5V supply.

    Operation at +/-1.75V may not be good. But if you think it is OK, start with same value resistors as 5V and might be able to reduce to optimize for lower voltage.

  • 0 in reply to Jim Karki
    Prodigy 20 points

    Hi Jim,

    Thank you for your advice, but for my application I really need to limit the output signal's amplitude to +/-0.8V. Once I finish the design of my PCB and test it I will give you feedback on how the OPA3695 behaves with lower power supply. I also have on more question regarding the disable pins. Is it really safe to left them floating for a normal amplifier operation?

    Thanks

     

  • 0 in reply to Cristina Oliveira
    TI__Expert 4950 points

    Hello Cristina,

    Yes, you can leave the diable pin of the OPA3695 floating.

    Best regards,


    Xavier