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I am using a dual op-amp package in a circuit, however I only need to use one. Is there anyway to disable the other op-amp so it doesn't inject electrical noise in my circuitboard? I think grounding the positive input and setting the op-amp into unity gain might be best, but I am not certain.

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That will do fine ... as long as the amp is unity-gain stable of course :) – MikeJ-UK Sep 18 '12 at 15:15
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For those who might not be following, the issue is that if you leave the inputs open and/or don't complete a negative feedback loop, there's a fair chance your op-amp output can hammer back and forth unpredictably between +/- rail and add noise to the circuit. – Scott Seidman Sep 18 '12 at 18:49

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A unity gain buffer is what this article also suggests. Quote:

The best thing to do with a surplus op-amp it is to use it. There are lots of places in an analog circuit where a buffer amplifier may improve performance - and a unity gain buffer uses no extra components.

Grounding the non-inverting input is fine if you have a dual power supply. If you use a single supply you better set the input to Vcc/2 with a resistor divider:

enter image description here

(from the same article)

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Can you elaborate on the need to to set the positive input to Vcc/2 in the single-ended supply case? – vicatcu Sep 18 '12 at 15:29
@vicatcu - the unreadable red text in the picture says: "Do not connect the input to V+ or V- as this may cause the output to try to swing past its supplies and saturate". Which will cause increased power consumption. – stevenvh Sep 18 '12 at 15:35
@vicatcu - I can second the recommendation in Steven's answer. Connection the + input to the half way point between the V+ and V- rail is the correct thing to do. --- It may have the additional benefit in that it makes places where wires can be attached in case a re-work ever requires the use of the op-amp. – Michael Karas Sep 18 '12 at 16:05
@MichaelKaras cool, I wasn't suggesting steven was wrong, just wanted to try and learn more from his answer – vicatcu Sep 18 '12 at 17:35
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@user1207381 - yes, you can generally pick any voltage within the common mode range (that keeps the output within it's stated range), VDD/2 is usually specified as it's generally the most convenient (e.g. 0V for dual rail) The key thing is not to let the output saturate. – Oli Glaser Sep 18 '12 at 23:40
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