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Driving PulSAR A/D directly from AD8221 in op-amp

Question asked by Damien on Jan 22, 2013
Latest reply on Jan 28, 2013 by Gustavo.Castro

Dear All,

 

I'm quite new on analog devices and not yet familiar with it.

 

I want to perform absolute measurement of signal. My searches leads me to a PulSAR AD7693 and AD8221 instrument op-amp. The gain of the instrument op-amp is set by an AD5270 digital potentiometer.

 

My question is basically, on the pulsar datasheet, it is specified a driver is required with some example. Would it be possible to directly interface the ad8221 to the pulsar without additional driver ?

 

The rise time is not an issue, the targeted absolute accuracy is about 0.1% of the measured value with a low drift over time (1yr). An external 2.5V voltage reference is used. The system is supplied on 3.3V single supply.

 

Also the GND of sampled signal and the logic is on the same pin, my layout separate logic and signal ground, where gnd would be tied to obtain best results ?

 

Thanks for your comment

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