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AN4021: Calculation of reverse losses on a power diode

1.1

Characteristics (curves)

Figure 1. Average forward power dissipation versus

average forward current (terminals 1 and 3 short

circuited)

0

2

4

6

8

10

12

14

16

18

20

22

0

2

4

6

8

10

12

14

16

18

20

22

24

26

28

δ = 0.05

δ = 0.1

δ = 0.2

δ = 0.5

δ = 1

T

δ = tp/T

tp

PF(AV)(W)

IF(AV)(A)

Figure 2. Average forward current versus ambient

temperature (δ = 0.5, terminals 1 and 3 short circuited)

0

2

4

6

8

10

12

14

16

18

20

22

0

2 5

5 0

7 5

100

125

150

Rth(j-a)= R th(j-c)

Rth(j-a)= 15°C/W

T

δ =tp/T

tp

T

(°C)

amb

IF(AV)(A)

Figure 3. Normalized avalanche power derating versus

pulse duration (Tj = 125 °C)

P

(tp)

P

(10 µs)

ARM

ARM

0.001

0.01

0.1

1

1

10

100

1000

t (µs)

p

Figure 4. Relative variation of thermal impedance junction

to case versus pulse duration

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

1.E-03

1.E-02

1.E-01

1.E+00

Single pulse

TO-220AB/I²PAK

tp(s)

Zth(j-c) /Rth(j-c)

STPS20SM100S

Characteristics (curves)

DS6172 - Rev 4

page 3/10