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Sensor interface, OP AMP, -500mV +500 mV to 0-5 V amplifier

Arouse1973

Adam
Dec 18, 2013
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Good comments from GPG. I assumed that since the sensor output -0.5 to 0.5V it was already amplified by an op amp, but apparently not. So a buffer amplifier is required before the summing (or differencing) amp.

One more thing, though:

Even a rail-to-rail amp will not allow the input to go all the way to zero with a single supply. So you should either use dual supplies, or map the range to something not including 0, such as 1-5V if you prefer to use a single supply.

Bob

Yes Bob, that's why I used -1 Volts, but it could be -5V. So a combination of my circuit and yours should fit the bill.
Adam
 

GPG

Sep 18, 2015
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Even a rail-to-rail amp will not allow the input to go all the way to zero with a single supply.
From LT1635 data
"The input common mode range of the op amp includes
ground"
 

BobK

Jan 5, 2010
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From LT1635 data
"The input common mode range of the op amp includes
ground"
Whoops, I meant output, not input. For the popular LM324 single supply opamp it can only go to about 40mV.

Bob
 

GPG

Sep 18, 2015
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Also the output will go to within 15mV of the rails into a high resistance load.
The only thing missing is whether a few nA input current is ok or should pA be required. OP?
 
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