On Tue, 2006-08-01 at 17:26 -0700, John Pearson wrote:
> I need to amplify the signal from a sensor into an ADC. I have very little analog experience or knowledge.
> 
> Circuit supply voltage is +3.3 volts.
> Output impedance of transducer is 1K typical.
> Full output voltage span of sensor is 35mV typical.
> Nominal input impedance of ADC is 10K.
> 
> I want to amplify the DC voltage from the sensor to the ADC as much as possible. Linearity, temp drift and offset is not too much of an issue.
> 
> Can this be done with perhaps a mosfet and a couple resistors? Is there a small package (like a TO92 or 3 pin package) that will do the trick?

Linearity with just a single mosfet and the range you're looking for
will be an issue.

Your best bet is an opamp. There do exist op amps in very small
packages. You don't mention frequency response, but you do mention
sensor and the PIC's ADC, so chances are you aren't in the >1MHz range
so nearly any modern op amp with true rail to rail will fit the bill.

TTYL

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