Hello All, This is a new thread related to my output stage setup. Only this time, rather than determining if something went wrong, I simply want to monitor the temperature of the MOSFET on the output stage. I have been doing a bit of research to see what kinds of sensors are available out there and I can see there are a lot of choices ranging from thermocouples to simple silicon temperature ICs with both analog and digital outputs. In my situation, I have one (possibly two) MOSFETs that will be mounted to this heatsink here: http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=HS349-ND#HS349-ND I would like to somehow get a reasonably accurate temperature readout of the heatsink so that I can monitor the temperature of the MOSFET(s) that are mounted to it. So far, I would like to use a temperature sensor that has a digital output so that I won't have to add an extra ADC to the board (the output stage is isolated from the digital side) to measure the temperature value. For that, I have found one good sensor that would work perfectly for the job (TC74A0-5) as it comes in a TO220 package and could simply mount on the back side of the heatsink to measure the temperature. The problem is that I really want to save that space for a second FET. Sooo... I found another sensor, the LM74, which also offers a digital output that I can read. It comes in a SOIC package, BUT I'm wondering how I would accurately take a temperature reading with it. Would it be sufficient to simply locate the sensor somewhere close to the heatsink or is there a better way to do it? I'm surprised that there are so many SMT sensor ICs out there but I'm dumbfounded to know how one would actually get an accurate temperature reading on a specific 'something' using those package types??? I also noticed that there is a nice selection of thermistors out there which I could also play with, but I think I'll still run into the same problem with those. Any suggestions appreciated. Thanks, Jason O P.S. as far as accuracy is concerned, I'm only looking for a resolution of 1 degree C.