From: Jim Thompson
Subject: Re: MOSFET "Normalized On-Resistance" question
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Date: Mon, 16 Dec 2002 21:13:46 GMT
NNTP-Posting-Date: Mon, 16 Dec 2002 16:13:46 EST
Organization: Cox Communications
On Mon, 16 Dec 2002 21:09:01 GMT,
jmuchow@SPAMMENOTcamlight.com (John Muchow),
In Newsgroup: sci.electronics.design,
Entitled: "MOSFET "Normalized On-Resistance" question",
Wrote the following:
|Looking at a data sheet for a MOSFET, I had a question about applying
|the information from a Normalized On-Resistance vs. Temperature graph.
|Assume the Rds(on), at 25-degrees C., of the MOSFET is 0.01-ohms and
|that my worst case junction temperature is 100-degrees C....all at
|max. rated amps.
|Looking at the graph, I see that the normalized resistance at
|25-degrees C. is 1. OK, that makes sense...it's normalized.
|If the normalized resistance at 100-degrees C. is 1.5, does that mean
|I multiply the actual Rds(on) of 0.01-ohms (at 25-degrees C.) by 1.5
|to get a Rds(on) of 0.015-ohms at 100-degrees C.?
|If not, how the heck do you derive the Rds(on) of a MOSFET at
|different junction temperatures? :-)
You are correct in your methodology.
| James E.Thompson, P.E. | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona Voice:(480)460-2350 | |
| Jim-T@analog_innovations.com Fax:(480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |
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