differential signals question

[sweethomela8]

The differential op-amp I'm using has a OUT+/OUT- output which gets fed into a differential input for a ADC to the IN+/IN-. Does it matter if you connect the OUT+ to the IN+ or IN- and OUT- to the IN+ or N-?

 

[WimRFP]

Hello,

When you change IN+ to IN- and vice versa, your ADC "sees" an inverted signal ( -1*(original signal) ). when it fits within the range of the ADC is should not be a problem.

 

[dominoeff]

hi:
i think if you connect the OUT+ to the IN- and OUT- to the IN+,you will get a common-mode feedback circuit.i am not sure when it is vice versa..

 

[WimRFP]

Hello,

When you have reasonable differential output, with low CM component) and a good differential input with good CMRR, and good supply rejection, I would not see the common-mode feedback effect.

When the common mode level of the output is supply dependent and there is some supply dependency in the ADC as well, yes, then you are right, having a twist in the signal path may result in different power supply rejection behavior. You should try this to see what connection is best