What to do with Free/Floating Opamp?

[TySN_Sound]

Building a buffer/splitter (1 in/2 out) with two tl072's. The first is only being used to buffer OUT 1, so the second opamp is free. Both opamps in the second chip are being used for OUT 2 buffer and phase invert.
I was curious what to do with the unused opamp.
Only need the phase invert on one of the outs. I've seen schematics with extra opamps being wired like a buffer, with the input going either to Vr or ground and the out just floating.
Why not just have all the extra pins go to ground?
Is there something else that I can use it for that I'm not thinking of?

Thanks!

[bluebunny]

You won't have seen the unused output just floating: the opamp would get upset.  It was more likely connected to the inverting input (like a buffer) and the non-inverting input connected, as you say, to V_REF.  That way, the unused opamp is in a happy place and it won't unintentionally upset the rest of your circuit.

[MikeA]

+1 to bluebunny, here's the reference for doing that:https://www.ti.com/lit/an/sboa204a/sboa204a.pdf

Or you can use the extra op amp half as a buffer for your reference voltage supply (Vref), if you're using one rather than a dual supply and referencing to ground. 

[TySN_Sound]

Thanks!

That doc explained exactly what I wanted!

[bluebunny]

MikeA's tip is spot-on too: using it to make your V_REF rock-solid is a good way to use up the unused opamp.