ZTP-135SR temperature sensor ..#2

Irving said:

Interesting device, but precious little application info on the web. Datasheet and 'training guide' attached.

Now to your problem... the thermopile outputs approximately -3mV at 0°C and +10.5mV at 100°C. Assuming a single ended ADC at 3.3v you need to amplify the voltage of the pile by about 200 - 240 - this is probably done with a small fixed amplification in one stage (say x10) and a following stage (x24) To get a resolution of around 2°C you need to reliably detect a 75uV change allowing for noise and opamp offset. That means you need to start by finding an opamp - or more likely an instrumentation amp - for the first stage with a low noise figure and sub-10uV offset. The device has a noise figure of 0.5 √nW/Hz so your amp will need to be in the same or near order of magnitude. This isn't going to be a common hobby op-amp on a breadboard if you expect any degree of accuracy or repeatability - PCB layout will matter too.

I don't have time right now to run the numbers...

Click to expand...