Datasheet avalanche ratings

AN2344

20/27

Equation 19

expressed as:

Equation 20

thus,

Equation 21

Figure 16.

Normalized STP11NM60FP impedante

By using Equation 15, a more accurate TJ value at avalanche onset can be calculated.

Modeling each power contribution as a rectangular pulse (see Figure 17.):

●

Pulse 1 (turn ON)

Equation 22

●

Pulse 2 (conduction)

Equation 23

●

Pulse 3 (turn OFF)

Equation 24

●

Pulse 4 (avalanche)

Equation 25

Tj

P

0.7P

PEAK AV

() T

CASE

++

=

Zth

()

3.57

K

•

61ns

() 0.00125° CW

⁄

=

≈

T

Jmax

()

45

2448

0.7

0.00125

70

117

° C

≈

+

•

•

+

=

t

1

40ns

0.71

28.4ns

=

•

=

td1

5.8ns

=

P1

0.7

256W

179W

=

•

=

*

*

t

2

2.4

µs 0.56 1.34µs

=

•

=

td2

1.06

µs

=

P2

0.89

17.3W

15.4W

=

•

=

*

*

t

3

60ns

0.71

43ns

=

•

=

td3

58ns

=

P3

0.7

672W

470W

=

•

=

*

*

t

4

86ns

0.71

61ns

=

•

=

td4

12.5ns

=

P4

0.7

2448W

1714W

=

•

=

*

*