Pulsed drain current (IDM)

AN2385

10/14

4

the package limitation and considering a very short power pulsed interval time. It depends

on the guaranteed maximum gate-source voltage and on the device trans-conductance at

gate voltage equal to the guaranteed maximum permissible gate-source value when the

transistor works in switching mode and not in the linear zone (see Figure 6.).

Figure 6.

In order to establish the Pulsed Drain Current interval time, avoiding that the junction

temperature overcomes the maximum guaranteed value, the Junction to Case Maximum

Effective Transient Thermal Impedance must be considered (see Figure 7.).

Figure 7.

Junction to case maximum effective transient thermal impedance for TO-

220 package.

Considering that the Dissipated Power is equal to:

Equation 7

P

D

R

DSON 175

° CI

DM

,

()

()

I

DM

2

•

=