identificationmosfetpowermosfet
Trying to figure out what this is, and suitable replacements. Markings are "1 Wt 77" Cannot seem to find anything.
Edit: I removed and sized it today, looks like 2.04 mm square package, exactly like the one on the below spec sheet… but not that part. Still cannot find those markings…
I imagine there are a bunch with the same pinning. They usually call this package a SOT-23-6 (for 6 leads..).
Generally you'd want 100V or so for PoE switch, for when the mosfet lets go of the coil, it will spring up some. If there is some snubbing maybe not too much, but I think 100V would be a safe bet.
What IC is used to control the FET? They usually are current mode and will sense the current in a small resistor from the switching FET's source to ground, <1 ohm usually. If we know the sense resistor and the SMPS IC, we can figure what the maximum current is also, to select a fet. :)
Edit: maybe I misinterpreted - is this switching the primary of the transformer? or just randomly somewhere in the circuit on the primary side? Might be for enabling PoE power to downstream parts, for example, after uh.. initiation. In that case, the protocol IC most likely limits current too - have to see it's datasheet to see if it switches the high side or the low side, etc.
It is a thermostat as Dave Tweed and Kaz noticed.
I got a similar one and it has the temerature written on it:
Best Answer
I removed and sized it today, looks like 2.04 mm square package that looks exactly like the one on the attached spec sheet... but not the same...cannot find those markings...
