AN869 APPLICATION NOTE

2/4

Where c is a thermal coefficient c

≈ 0.055

Rth(j-a) = Rth(j-c) + Rth(c-a)

Tj max is given by:

Tj max = 127°C

Second example:

Application parameters:

(1-

δ) = 0.5

Rth(c-a) = 18.5°C/W

Diode parameters (STPS10L25D):

Rth(c-a=) = 1.6°C/W

and

Tj max = 144°C

CONCLUSIONS

This application note shows that the maximum limit of Tj of the SCHOTTKY diodes given in the datasheet

is mainly due to the thermal runaway phenomenon. This limit doesn’t only depend on diode parameters

but also application parameters. In the first example corresponding to a typical application we will find Tj

max given in the datasheet. The second example shows that in some applications SCHOTTKY diodes can

be used with a junction temperature higher than the Tj max given in the datasheet.

,

()

1

–

()cRth j a

–

()

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

=

Tjmax

125

=

1

C

----

In

,

()

,

()

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

+