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AN316

Calculation example

17

Equation 9

5.1.5

Temperature correction

The voltage at 75 °C is:

Equation 10

This value is below the 50 V limit. This Transil ensures the protection.

5.2

Repetitive surges

We have to protect the transistor shown inFigure 11 with a Transil having its clamping

5.2.1

Calculation method

repetitive surges.

D

R

+

≈

)

(at

-

≤

V

V

A

84

.

39

)

(

5

.

11

32

05

.

35

4

.

48

5

.0

35

)

5

.

11

(at

=

×

-

+

≈

V

CL max

V

CL max

I

P

V

BRtyp

I

P

D

R

D

R

D

R

V

CL

V

CL

V

BR

V

CL

V

CL

×

V

V

C

CT

81

.

41

)

(

)]

25

75

(

1

[

84

.

39

)

75

(

)]

25

(

1

[

)

25

(

)

(

-

×

+

×

=

°

-

×

+

×

°

=

α

V

CL

V

CL

CL

V

CL

T

j

T

j

V

CL

V

CL

C)

75

(=

°

V

CL

V

CL

-

10

9

.

9

4

C

°

C

°C

°

×