TN1156 Datasheet, PDF (1/10 Pages) STMicroelectronics – Irradiated HV Power MOSFETs working in linear zone

TN1156
Technical note
Irradiated HV Power MOSFETs working in linear zone: a
comparison of electro-thermal behavior with standard HV products
Introduction
This paper studies the thermal instability phenomenon of irradiated HV Power MOSFET
devices working in linear zone operating conditions and compares their electro-thermal
behavior with standard products. Experimental results show that irradiated devices have
more thermal instability than standard devices, therefore, they should be used carefully in
these particular operating conditions.
In most of cases, Power MOSFETs are used in switching operating conditions where
R_DS(on) is the key parameter to evaluate the device’s performance. However, in some
special cases, devices work in linear zone. A Power MOSFET works in linear zone when
high-currents and high voltages are together applied to MOSFET terminals. Power
MOSFETs are used in linear zone in some dedicated applications especially in automotive
segment such as: standard topologies of audio amplifiers, linear DC-DC converters, DC fan
controllers, electronic loads, current mirrors, smart fuses, etc… In many of these
applications, typically, the LV Power MOSFETs are used. Furthermore, Power MOSFETs
work in linear zone for a short period of time when they are used in switching conditions
during the Miller region where high-currents and high voltages are together applied to
MOSFET terminals. This means that the thermal instability must be also evaluated in
applications where linear zone isn't the typical operating condition. Therefore, this
phenomenon needs to be evaluated even during the slow switching process either in LV or,
in particular, in HV Power MOSFETs when high inductive loads are driven. Considering a
theoretical Power MOSFET FBSOA, linear zone is referred to that area delimited by
maximum allowed dissipated power for different power pulse duration.
December 2013
DocID025511 Rev 1
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