Reference Pin on Differential Amplifier

  • #1
195
5
I want to use a differential amplifier to separate the digital and analog ground portions of a circuit, but am not confident in my understanding of the datasheet of the amps I have on hand (amp03).

http://www.analog.com/media/en/technical-documentation/data-sheets/AMP03.pdf

I think that (looking at page 5), the output of the amp will be referenced to whichever ground I connect to the reference pin (pin #1). Does this make sense? For example, I plan to power the amp from a supply (floating lab supply) referenced to analog ground, but want it's signal to go into an Arduino (powered by a wall wart), so I would connect the reference pin to digital ground in that case.
 

Answers and Replies

  • #2
Baluncore
Science Advisor
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so I would connect the reference pin to digital ground in that case.
Yes, if the digital ground on the Arduino is the ground reference for the A-D converter.
 
  • #3
195
5
Thank you. Specifically for my circuit I would like:

signal in wrt analog ground --> [amp03] --> Arduino+A-D (ref. to Ardunio ground) --> [amp03] --> signal wrt analog ground
 
  • #4
Baluncore
Science Advisor
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Currents flowing in the ground conductors can be a problem. You can minimise noise and DC offsets by making sure that the reference terminal is attached as close as possible to the Arduino ground pin.
 

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