SSM2141

REV.

–6–

MAINTAINING COMMON-MODE REJECTION

In order to achieve the full common-mode rejection capability

of the SSM2141, the source impedance must be carefully

controlled. Slight imbalances of the source resistance will result

in a degradation of DC CMR—even a 5

Ω imbalance will

degrade CMR by 20 dB. Also, the matching of the reactive

source impedance must be matched in order to preserve the

CMRR over frequency.

Figure 1. Precision Difference Amplifier. Rejects

Common-Mode Signal =

2

by 100 dB

Figure 2. Precision Unity Gain Inverting Amplifier

Figure 3. Precision Summing Amplifier

Figure 4. Precision Summing Amplifier with Gain

Figure 5. Suitable Instrumentation Amplifier

Requirements can be Addressed by Using an

C