LAB WM440 - Safe Operating Area

Improving Reliability By monitoring Device Stress Limits.
LeCroy Application Brief No. LAB440

Safe Operating Area
Improving Reliability By monitoring Device Stress Limits
Every switching device has a
maximum voltage, maximum
current and maximum power
specified by the device manufac-
turer, displayed on its technical
application note. Reliability of
the power supply is dependent
on not exceeding these limits.

In figure 1 the upper trace shows
a MOSFET's drain-source volt-
age, and the lower trace shows
the MOSFET's drain current
waveform. Amplitude of current
vs. amplitude of voltage is dis-
played as an XY trace known as
a Safe Operating Area Plot
(SOA). The lower left corner of
the XY plot shows zero current
and zero voltage. The upper- Figure 1 - A Safe Operating Area Plot for