Op Amp CMRR calculator | Op Amp CMRR formula

This page covers Op Amp (Operational Amplifier) CMRR calculator. It mentions Op Amp CMRR formula used in this CMRR calculator. The CMRR stands for Common Mode Rejection Ratio. Refer Op Amp for more information on Operational Amplifier basics.

CMRR Calculator #1 Using Ad and Acm in numerical

Following calculator uses numerical values of Ad and Acm for CMRR calculation.

EXAMPLE: Op Amp CMRR Calculator 1:
INPUTS:
A_D = 2, A_CM = 10000
OUTPUTS:
CMRR (Numerical) = A_D/A_CM = 0.0002
CMRR (dB) = 20*Log₁₀ (CMRR(Numerical)) = -73.97

CMRR Calculator #2 Using Ad and Acm in dB

Following calculator uses decibel (dB) values of Ad and Acm for CMRR calculation.

EXAMPLE: Op Amp CMRR Calculator 2:
INPUTS: A_D in dB = 6, A_CM in dB = 80
OUTPUTS: CMRR (dB) = 6 - 80 = -74 dB

Op Amp CMRR Formula

Following Op Amp CMRR formula or equation is used for calculations by this CMRR calculator.

CMRR is defined as ratio of differential Gain (A_D) to Common Mode Gain (A_CM). For 741C Op-Amp, it is typically 90 dB.

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