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Reply-To: "fred bartoli"
From: "fred bartoli"
Subject: Re: CMMR op amp outside voltage rails ?
Date: Wed, 4 Dec 2002 11:19:12 +0100
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Organization: Guest of ProXad - France
NNTP-Posting-Date: 04 Dec 2002 11:16:11 MET
Gibbo a écrit dans le message :
> I have simulated and breadboarded (they almost agreed !) an amplifier that
> need with the following specs:-
> Differential voltage input of -60mV to +60mV
> This could be sitting on an offset between -5 volts to +50 volts
> Available power supply is a single rail 5 or 6v (not yet decided)
> Gain of 50 and 500 (switchable)
> Bandwidth DC to 1KHz
> Gain accurancy better than 1%.
> Offset accuracy less than 0.05 volts on the output.
> Temperature/time drift of offset is not such an issue as the micro
> calibrates for this. Though of course it would be nice to remove this
> My solution uses 3 op amps. One of them to remove the offset on the input.
> as the differential amp, and one for the gain There has to be a less
> complicated way.
> I bet there's a single package that will do it all ?
Chris, you didn't tell about the needed input impedance.
What is your requirements ?
If you can live with 100Kohm order BB-Ti has some difference amplifier with
high common mode range. Look at INA146/148.
The 146 is probably the one you want.
> Ideas ?
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