Use this electronics calculation for a first-pass component, converter, signal, motor, or sensor estimate when the stated operating conditions and units match the device data.

Differential gain

Required number input.

Common mode gain

Required number input.

Compute the common-mode rejection ratio in decibels as 20 x log10(differential gain / common mode gain). The tool evaluates the supplied inputs together and returns the named outputs below; it does not infer omitted operating conditions or change the units shown.^[1]

CMRR (dB)

The resulting cmrr returned as a number.

• Amplifier gain and rejection calculations are small-signal approximations unless the operating point is checked. Gain-bandwidth, slew rate, input and output range, stability, noise, offset, bias current, loading, and frequency-dependent CMRR can limit the result.
• Use finite inputs in the displayed units and preserve more precision than the final presentation requires. Independently verify safety-critical, financial, compliance, or production decisions.

Check the result against the current datasheet and worst-case operating corners, then verify the circuit or measurement with simulation and bench testing where failure matters.

• Instrumentation Amplifier Cmrr Calc

  Common-mode rejection ratio in decibels from measured differential and common-mode voltage gain magnitudes.

• CMRR Linear

  Compute the linear common-mode rejection ratio as Adiff / Acm; the common-mode gain must not be zero.

• PSRR dB

  Compute the power supply rejection ratio in decibels as 20 x log10(delta Vsupply / delta Vout); both deltas must be positive.