What is the CMRR in decibels (dB) for a typical 741C op-amp? Given the typical open-loop differential gain for the 741C is 200,000 and the typical commonmode gain is 6.3.

Answer 1

The CMRR in decibels (dB) for a typical 741C op-amp can be calculated using the formula:

CMRR(dB) = 20 log10 (open-loop differential gain / common-mode gain)

Substituting the values given:

CMRR(dB) = 20 log10 (200,000 / 6.3)

CMRR(dB) = 20 log10 (31,746.03)

CMRR(dB) = 90.31 dB (rounded to two decimal places)