ADA4522 CMRR spec

splin on Jun 23, 2016

In the datasheet rev D, CMRR is specified as 155dB typical @ 5V and 160dB for 30V operation, yet figure 30 shows it to be only 110dB from 10Hz to 100Hz, declining thereafter. Presumably the graph is in error?

Is CMRR normally specified at DC?

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0 Emman.A

on Jun 22, 2016 5:37 PM
Hi Tony,

The CMRR performance in the specs table is DC CMRR. If you are going to extend figure 30 down to DC using ideal setup, it should yield to the same DC CMRR performance. Therefore I would say that both measurements are correct.

Depending on the common mode voltage (CMV) present on your circuit, you can refer to specs table if it is DC CMV or in figure 30 if it is AC CMV to compute for its error contribution on the system

I hope this helps.

Best regards,

Emman
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0 Emman.A

on Jun 22, 2016 5:37 PM
Hi Tony,

The CMRR performance in the specs table is DC CMRR. If you are going to extend figure 30 down to DC using ideal setup, it should yield to the same DC CMRR performance. Therefore I would say that both measurements are correct.

Depending on the common mode voltage (CMV) present on your circuit, you can refer to specs table if it is DC CMV or in figure 30 if it is AC CMV to compute for its error contribution on the system

I hope this helps.

Best regards,

Emman
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