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

[Arouse1973]

And if dual rail needed a switched capacitor converter will do eg:
http://www.analog.com/en/products/p...itor-converters/adm8829.html#product-overview

Good call. I have used these before for just this purpose.
Adam

 

[Arouse1973]

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

 

[BobK]

Okay, I missed that Adam.

Bob

 

[GPG]

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]

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

 

[Arouse1973]

Whoops, I meant output, not input. For the popular LM324 single supply opamp it can only go to about 40mV.

Bob

LOL I thought you did.
Adam

 

[GPG]

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?

 

[Amin Hajihosseinlu]

Thank you guys, Lots of useful information, I am gonna go over them.