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High current op-amp, small through-hole package

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Marco Trapanese

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Jul 20, 2008, 6:29:44 PM7/20/08
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Hello,

I need an op-amp for a buffer application (in DC) with this features:

* single supply: +5V
* high output current: > 100 mA
* package: through-hole, small as possible like TO220 or metallic case

What would you recommend?

Thanks!
Marco / iw2nzm

Mook Johnson

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Jul 20, 2008, 7:57:30 PM7/20/08
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"Marco Trapanese" <marcotrapa...@gmail.com> wrote in message
news:g60e98$thl$1...@tdi.cu.mi.it...

Is the current always being sorced or sunk into the opamp. If so then an
emitter follower with a NPN (for sourcing) or PNP (sinking) would do the
trick.

If you can take some small zero cross distortion you cna place a totem ploe
(npn/pnp stacked) on the output and take the feedback from the emitters.
With a reasonably fast Opamp the crossover distortion will be small when
viewed on the scope. If you going for a high fidielty (audio) you may need
something more elaborate.

Linear and National used to make some nice buffers but I think they're
going. Now that I'm tiniking about it National makes some "boomer" series
power opamps than source some current. have a look.

TI also has some power opamps.



Marco Trapanese

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Jul 21, 2008, 3:23:14 AM7/21/08
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Mook Johnson ha scritto:

> Is the current always being sorced or sunk into the opamp. If so then an
> emitter follower with a NPN (for sourcing) or PNP (sinking) would do the
> trick.
>
> If you can take some small zero cross distortion you cna place a totem ploe
> (npn/pnp stacked) on the output and take the feedback from the emitters.
> With a reasonably fast Opamp the crossover distortion will be small when
> viewed on the scope. If you going for a high fidielty (audio) you may need
> something more elaborate.


Nope. I only have to buffer a Vref of a DAC (2V). So using an NPN after
a buffer should do the trick if I have the space to place both op-amp
and bjt.

Thanks!
Marco / iw2nzm

MooseFET

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Jul 21, 2008, 9:51:25 AM7/21/08
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On Jul 20, 3:29 pm, Marco Trapanese <marcotrapaneseNOS...@gmail.com>
wrote:

How about abusing a regulator like the LT3080. If the load is always
sinking it works as a voltage follower with a low offset voltage.


Marco Trapanese

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Jul 21, 2008, 10:18:52 AM7/21/08
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MooseFET ha scritto:

> How about abusing a regulator like the LT3080. If the load is always
> sinking it works as a voltage follower with a low offset voltage.


It could be an idea. Thanks for the input

Marco / iw2nzm

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