•

AN4021: Calculation of reverse losses on a power diode

1.1

Characteristics (curves)

Figure 1. Average forward power dissipation versus

average forward current (per diode)

0

5

10

15

20

25

30

0

5

10

15

20

25

30

35

T

δ=tp/T

tp

PF(AV)(W)

δ=0.1

δ=0.2

δ=1.0

IF(AV)(A)

δ=0.05

δ=0.5

Figure 2. Average forward current versus ambient

temperature (δ = 0.5, per diode)

0

5

10

15

20

25

30

35

0

25

50

75

100

125

150

175

I

(A)

F(AV)

T

δ=tp/T

tp

Tamb(°C)

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

Rth(j-a)=15°C/W

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

t (s)

p

Z

/ R

th(j-c)

th(j-c)

Single pulse

STPS60150C

Characteristics (curves)

DS4090 - Rev 2

page 3/10