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

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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  • 0
    •  Analog Employees 
    on Jan 22, 2013 10:56 PM

    Hi Damien,

    Thank you for considering Analog Devices for your circuit needs. For your question whether the AD8221 can directly drive the AD7693, the answer is yes. But you need to configure the two devices properly in order for the output of the AD8221 stay within the input range of AD7693.

    I checked both the AD8221 and AD7693 to see if they meet your system requirements. Unfortunately, both the AD8221 and AD7693 cannot operate on 3.3V single supply. AD8221 operates on a minimum dual supply of +/-2.3V while AD7693 can have a supply voltage as low as 4.5V.

    Could you describe more on the signal (peak voltage, bandwidth, etc) you want to process? ADI offers a wide range of amplifiers and AD converters that could be used for your application.

    Best regards,

    Neil

Reply
  • 0
    •  Analog Employees 
    on Jan 22, 2013 10:56 PM

    Hi Damien,

    Thank you for considering Analog Devices for your circuit needs. For your question whether the AD8221 can directly drive the AD7693, the answer is yes. But you need to configure the two devices properly in order for the output of the AD8221 stay within the input range of AD7693.

    I checked both the AD8221 and AD7693 to see if they meet your system requirements. Unfortunately, both the AD8221 and AD7693 cannot operate on 3.3V single supply. AD8221 operates on a minimum dual supply of +/-2.3V while AD7693 can have a supply voltage as low as 4.5V.

    Could you describe more on the signal (peak voltage, bandwidth, etc) you want to process? ADI offers a wide range of amplifiers and AD converters that could be used for your application.

    Best regards,

    Neil

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