June 2006

Rev 1

1/14

AN2385

Application note

Power dissipation and its linear derating factor, silicon

Limited Drain Current and pulsed drain current in MOSFETs

Introduction

Datasheets of the modern power MOSFET devices, either of low voltage or of high voltage,

show in the section entitled "Absolute Maximum Rating" the values of some important

parameters that regard the SOA (safe operating area). As it is well kwown in literature, SOA

conditions.

These important parameters are studied in this technical article. In particular, attention will

be focused on the Power Dissipation and its Linear Derating Factor, Silicon Limited Drain

Current and Pulsed Drain Current. This technical article will explain what these parameters

are and how they can be calculated. It will recall some basic and simple technical concepts

and can be a useful tool for customers to understand and facilitate reading of a power

MOSFET datasheet.

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