Instrumentation amplifier question

Discussion in 'General Electronics Chat' started by msr, Sep 14, 2010.

  1. msr

    Thread Starter Well-Known Member

    Jul 8, 2008

    Can I use an instrumentation amplifier like a common opamp?

    In particular, I would like to know if I can use a INA118 like an opamp inverting circuit?

    Thanks for your help!
  2. Audioguru

    AAC Fanatic!

    Dec 20, 2007
    If you look at the datasheet of the instrumentation amplifier, you will see that it already has negative feedback and its gain is set completely differently than an opamp.
    With an opamp, you must add your own negative feedback that determines the gain.

    If you add a gain-setting resistor then an instrumentation amplifier makes an inverting amplifier with a very high input impedance.
  3. schmitt trigger

    Active Member

    Jul 12, 2010
    Additionally there are some common mode range vs output voltage limitations which are dependent on the gain. See the plots on page 4.