Can anyone let me know the connection of INA122 to ADS7861

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Ken750

Joined: 03 Nov 2009
Posts: 3

04 Nov 2009 18:56 Can anyone let me know the connection of INA122 to ADS7861

Hi, everybody. I need to connect an instrument amp to ADC. The instrument amp i am using is INA122 where its has one output voltage while the ADC i need to use is ADS7861 which has dual inputs..... The ADS7861 has Ao, A1 , Bo and B1 input.... i am not sure how to connect the INA122 to these inputs....

Sorry for my poor english and i hope you guys can understand.....

Thank you for help in advanced.

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FvM

Joined: 22 Jan 2008
Posts: 5154
Helped: 766
Location: Bochum, Germany

04 Nov 2009 20:56 Can anyone let me know the connection of INA122 to ADS7861

A scheme for the connection of a single-ended signal source is provided in the ADS7861 datasheet: Connect the - input to REFout and the + input to the source, referenced to REFout. With an instrumentation amplifier, connecting the Ref pin also to REFout would achieve this. As another point, you should limit the ADC input voltage to the allowed 0..+5V range. Assuming a +/- 5V INA122 supply, a schottky clamp to GND would be sufficient. In case of a +5V single supply, no clamp circuit is needed.