[sdiy] VReg as op amp bias source

[David G. Dixon]

> Is there anything stopping me from using a VReg as a bias source for the
> non-inverting pin of an opamp?

Sounds like an excellent idea to me.  I do it all the time.

> Current concerns aside - if I had, for example, 6 op amps that all needed
> the non-inverting pin biased to VCC/2 - is there a reason why I
> couldn't/shouldn't set up an LM317 at VCC/2 and run them off that?

What would those current concerns be?  Opamp inputs don't admit any current
(or, at least, shouldn't).  Therefore, if all you are doing is supplying a
reference voltage to the + pins of opamps, the current draw from the
regulator should be negligible.  You could still use the same regulator to
power other things which do draw current (I do that all the time too).

> Obviously for VCC/2 I *could* just use 2 x 10K resistors - but I have a
> requirement for a bunch of voltage references that are going to make
> resistor selection a little difficult.

Plus, using one regulator for the lot ensures that they are all receiving
the same reference, and saves about 12 resistors on your board.  What's the
downside?