Error due to CMR for current sense amp

Thread Starter

RamaD

Joined Dec 4, 2009
328
AD8206 current sense amplifier has a min. CMRR of 76dB (6310) and a fixed gain of 20. If my common mode voltage is 13.6V, then the worst case error due to CMR is

13.6V/6310 = 2.16mV, referred to the input, or
2.16mV * 20 = 43.2mV at the output.

Will it be this high? Or am I calculating wrongly?
 

Thread Starter

RamaD

Joined Dec 4, 2009
328
Thank you Crutschow.
Actually there was a problem with a uC based charger being designed by a friend. The current was 0.7A(!) when the charger breaker was off, though the shunt was on the battery side connected to the uC.
I managed to get a pin compatible INA282, with 120dB CMRR, though the gain is 50. Thanks again.
 
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