Re: Driving an OP AMP input with no VCC

On Wed, 08 Nov 2006 16:01:56 +0100, Fred Bartoli
<fred._canxxxel_this_bartoli@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx> wrote:

Jim Thompson a écrit :
[snip]

All inputs and outputs................... VSS ?0.3 V to VDD +0.3 V

I think you will find most, if not all OpAmps have this restriction,
so you need some way to protect it.

Post your schematic on a.b.s.e and everyone here will take a look.

...Jim Thompson

So it's time for some update.
Have a look at "over the top" opamps or comparators like LT1716 or LT1782...
Bias current is going high over the supply rail, but it is OK for some
applications.

It just occurred to me that the LM324 can take inputs > VCC.

...Jim Thompson
--
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice:(480)460-2350 | |
| E-mail Address at Website Fax:(480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.
.

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