Dave Tweed wrote:
> If you really need to output 0.0 to +10V with low source impedance
> over
> the whole range, I really think you're going to have to bite the
> bullet
> and provide a negative supply, in which case, you can just use the
> original opamp.
>
> It was simply a Bad Idea(TM) to try to do this with a single supply.

Yes, and a simple charge pump like is often used for this isn't going to be
tractable at 100mA.  Mostly likely you'll need a real inductive switcher.

Another things to consider is the deadband between two emitter followers
(NPN and PNP) with the bases simply tied together.  Does it need to source
and sink 100mA, or is the direction known, like always source for example.
If it does have to switch between sourcing and sinking randomly depending on
the load, then you have to consider the deadband.  Maybe it's no problem
depending on what you're trying to do.  The feedback will make the opamp
jump over the deadband quickly, but that still causes distortion in the
output.  Whether you need a single transistor emitter follower, two
transistors, or something more complicated depends on the load and what the
signal will be used for.


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