From: "Phil Allison"
References: <email@example.com> <firstname.lastname@example.org>
Subject: Re: Question about linear derating factor for MOSFETs
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Date: Sun, 10 Nov 2002 12:28:34 +1100
NNTP-Posting-Date: Sun, 10 Nov 2002 12:18:57 EST
Organization: Telstra BigPond Internet Services (http://www.bigpond.com)
"John Muchow" wrote in message
> >>> ** No, the case temp will need to be measured. It will have a
> >>>significant thermal loss depending on mounting arrangement and the
> >>>temp of the heatsink immediately under the device pack is the one that
> Ahh...of course, makes sense now. Seems like I could derive the case
> temp knowing the load, the heat sink temp (under load), the calculated
> junction temp, and the thermal resistances of the device (theta-jc)
> and the thermal grease?
> Otherwise, the heat sinks I'm considering have a hole drilled to
> directly underneath the center of the mounting location for the
> MOSFET. I can use that for a thermistor. Actual temperature
> measurement, for me, is the best way to verify performance for this
** I find a K type thermocouple ( the kind with a bead on end of wire)
very useful for package temp measurements. Attach the bead with a clamp
pegs and alligator clips are OK )and some thermal grease for best accuracy.