Happy new year all!

I'm wondering how to correctly use the reference pin on an INA128 Instrumentation Amplifier. Is there a way to use this pin to eliminate negative voltages (i.e. do a voltage shift)?

Thanks again.

  • 1
    \$\begingroup\$ Yes, you can do a voltage shift through InAmp's REF pin. A very similar question was posted today. \$\endgroup\$ – Nick Alexeev Jan 1 '13 at 4:14
  • \$\begingroup\$ Thanks, that's what I am looking for. In the schematic on the reference section, how would you add the decoupling cap and what value? \$\endgroup\$ – user1883691 Jan 1 '13 at 4:28
  • \$\begingroup\$ Using this pin wrong can kill your CMMR, so be a bit careful. \$\endgroup\$ – Scott Seidman Jan 1 '13 at 12:51

The reference pin is exactly for level shifting the output. Note that it is best to use a low impedance source for this.An op amp as a unity gain buffer or other configuration should ideally drive this pin.

For decoupling take a look at the typical application circuit in the datasheet. It recommends a 0.1uF capacitor. Perhaps an extra 10uF capacitor would also be good.


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