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AD8418/AD8206/etc Vref current, noise rejection?

Question asked by jasont on May 22, 2015
Latest reply on Jun 8, 2015 by jasont

I am considering the AD8418 or similar device for bidirectional current measurement. One option is to connect Vref1 directly to Vs (positive supply) as shown in Figure 1 of the data sheet, but I am concerned about the effect of noise from the supply into Vref. The PSRR for Vs is listed at 80dB min but I assume this does not apply to Vref1.

 

Is there spec similar to PSRR to describe the effect of Vref1 noise on output accuracy?

 

If I connect Vref1 to a voltage reference then I need to know how much current this pin sinks. Is this information available? I assume this current is very low but I would like to be certain.

 

Thanks - Jason

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