OPA172: Programming amplifier gain

Kumar Balaji

Intellectual 410 points

Part Number: OPA172

Hi,

I am facing trouble in setting the gain of the OPA172 amplifier.

I want to set 20 as gain.

Should i go through the formula(1+R3/R4) or by the traditional formula (-Rf/Rin)

Please advice.

Thanks,

Kumar.V

over 6 years ago

0 Ron Michallick over 6 years ago

TI__Guru**** 169086 points

Kumar,

Note that 1+R3/R4 is always positive assuming R3 and R4 are positive; -Rf/Rin is always negative (inverting) assuming Rf and Rin are positive.
Your gain of 20 is positive.

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OPA172: Programming amplifier gain