On a neat compact SMD device as 3 stage cold alarm, preset temps. I wish to lower the presets about 3 degrees, powered for 10 years of a small Li cell. Assuming no temp sensor inside the PIC chip, 3 pin SMD marked U1 on the overlay, and code marked AZP18, is probably a temp sensor. No info found with that top code, would anyone know of a similar 3 pin,device type number with a datasheet to perhaps see if possible to fudge/gludgearound this one ? Failing that , an interim measure is to keep it on the top of an otherwise irrelevant itam,a permanently on, mains powered device, that is 2 degrees C above ambient
temp sensor 3pin IC, marked AZP18
Jul 18, 2016
2 Replies
Assuming its overall function is like an LM35 then half a chance to mod.
3Rs connected to the device,10K,18K,6.9K so assuming no data found on AZP18 then first try ,in turn, 100K,180K,69K over each and see what happens, then try an epitaxial diode cut in there somewhere if nothing emerges in function change.Adding R over first choice, set error code generation. R over second choice and operating band rose 8 deg C, so remove and up the resistance of the original one , if the third one paralleled does not decrease the operating zone
Join the Discussion
Have something to add? Share your thoughts — no account required.
Didn't find your answer?
Ask the community — no account required