>30V output AND 0V offset from a single op-amp?
- From: Lostgallifreyan <no-one@xxxxxxxxxxx>
- Date: Wed, 26 Apr 2006 01:00:11 GMT
CA3140 data sheets show that the output can approach the positive rail and
(allegedly) reach the negative rail. This might be false. On a single rail
supply the offset cannot be trimmed to get a true zero output, you MUST
have some negative.
I want to measure up to 30 watts at 1W/V from a thermopile sensor, on a
multimeter, so my idea is a split rail supply whose total is 34 volts, with
30 volts on the positive side and just a few hundred mV for negative, toget through-zero adjustment for offset error.
Will this work without frying the IC? Can anyone suggest common, low price,
good performing IC's for this? It doesn't have to be a single rail op-amp,
it just has to accept a VERY asymmetrical split rail. I'm hoping the LF411
or LF412 (with external offset trim) can do this.
I can make the dual supply stage, that's not the tough bit, but I'd like
some advice about the extreme asymmetry I want for the gain stage. (Both
will hopefully be workable from one dual op-amp IC).
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PS. Sorry about the repost, but I really want some help here, and my last
post got entirely lost behind the mark-up debate. I've reduced this post a
LOT to try to gain some attention to it. :)
.
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