Op Amp CMRR Calculator and Formula

This page provides an Op Amp (Operational Amplifier) CMRR calculator and explains the Op Amp CMRR formula used in the calculator. CMRR stands for Common Mode Rejection Ratio.

CMRR Calculator - 1: Using Ad and Acm in Numerical Form

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

EXAMPLE:

• 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

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

EXAMPLE:

• A_D in dB = 6
• A_CM in dB = 80

OUTPUTS:

• CMRR (dB) = 6 - 80 = -74 dB

Op Amp CMRR Formula

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

CMRR is defined as the ratio of differential Gain (A_D) to Common Mode Gain (A_CM).

For a 741C Op-Amp, the CMRR is typically 90 dB CMRRCalculator from ”./elements/CMRRCalculator.astro”; import OpAmpCmrrCalculator from ”./elements/OpAmpCmrrCalculator.astro”;