Opamp Termination Question for the Hivemind . . .

[Cybercow]

Which of the two unused opamp termination configurations is correct?
The TI spec sheets say "B".
Other internet finds suggest "A".
And others still suggest either is OK.

Your thoughts and why please?

 

[BuddytheReow]

 

[BuddytheReow]

*stares at the screen for a minute*

No, they're not the same. I don't think it matters which way with the unused opamp. As long as it's not just hanging there unattached to anything, you're good.

 

[Cybercow]

*stares at the screen for a minute*

No, they're not the same. I don't think it matters which way with the unused opamp. As long as it's not just hanging there unattached to anything, you're good.

I'm thinking there would be some sort of different between using the negative feedback vs the positive feedback. ????

 

[grahjm2a]

Listen to the spec sheet. You should use 'B'. There, the negative feedback will create a stable, unity gain voltage follower from the (unchanging) input.

The positive feedback shown in 'A' will make an oscillator. That creates potential for a problem as some small portion of the oscillating signal will leak into the other channels in the part and create noise.

 

[Feral Feline]

I'd go with the TI recommendation, but only because I would think they'd know what to do give they're the ones making the unused op-amp I'd be trying to button up...

 

[Cybercow]

I'd go with the TI recommendation, but only because I would think they'd know what to do give they're the ones making the unused op-amp I'd be trying to button up...

That was my thinking from the start. Thank you.