Hey there, I'm about to design a sensor circuit which is to be outside the whole year. I took care that most of the ICs are able to deal with temperatures from -20 to 30 degrees. Unfortunately though, the photodiode/transimpedance amp IC (OPT101) is within spec only at temperatures > 0 degrees. Now... I've got a couple ideas but I'm more or less lost at what you can do about that. 1) Have a small load resistance at the output, so that the increased current through the IC will heat it by itself...? (A voltage regulator for example would hardly need heating, would it?) Problem: The output is logarithmic to the irradiance. High current will flow only when there is "a lot" of light. What about (cooold) mornings...? 2) Have some kind of heating. What would you guys recommend? Halogen lamp (hidden away form the light sensor obviously)? PTC heating? I will most probably have a temperature sensor -near- the circuit as well, so the more local the heating, the better. Any ideas? Thanks in advance!