AN2385

Pulsed drain current (IDM)

11/14

junction temperature and at the Pulsed Drain Current value, and that:

Equation 8

Equation 9

Thus, considering a specific Power Pulse with a fixed duty cycle, the maximum Rectangular

Pulse Duration can be achieved.

As example, Figure 8. shows the determination of the maximum Rectangular Pulse Duration

as:

Equation 10

Figure 8.

Determination of the maximum rectangular pulse duration

In this example, the maximum Rectangular Pulse Duration equals 30usec. For power pulse

of higher duration the junction temperature overcomes 175°C and the device could fail.

It is important to highlight that the measured on resistance must be performed at the

maximum junction temperature and also at the specific Pulsed Drain Current. In fact,

taken into account.

P

D

Z

THJC

•

TT

JMAX

25

° C

–

=

∆

=

Z

THJC

T

JMAX

25

° C

–

R

DSON175

° CI

DM

2

,

()

------------------------------------------------

=

Z

THJC

175

° C25° C

–

20

10

3

–

600

•

2

•

-----------------------------------------------

0.021

° C

W

-------

•

=

=