1N5820, 1N5821, 1N5822

http://onsemi.com

5

Figure 1. Maximum Reference Temperature

1N5820

Figure 2. Maximum Reference Temperature

1N5821

Figure 3. Maximum Reference Temperature

1N5822

Figure 4. Steady−State Thermal Resistance

15

2.0

115

125

105

30

4.0

125

115

105

95

85

75

L, LEAD LENGTH (INCHES)

1/8

0

25

20

15

10

5.0

0

2/8

40

95

85

75

5.0

3.0

4.0

7.0

10

20

5.0

7.0

10

15

20

3/8

4/8

5/8

6/8

7/8

1.0

40

35

30

BOTH LEADS TO HEATSINK,

EQUAL LENGTH

MAXIMUM

TYPICAL

50

40

28

20

15

10

8.0

15

115

105

95

85

75

5.0

3.0

4.0

7.0

10

20

50

40

28

20

15

10

8.0

125

30

50

40

28

20

15

10

8.0

0.2

0.5

1.0

2.0

5.0

10

20

50

100

200

500

1.0 k

2.0 k

5.0 k

10 k

0.05

0.03

0.02

0.01

0.1

t, TIME (ms)

0.5

0.3

0.2

1.0

LEAD LENGTH = 1/4

″

TIME

equivalent square power pulse.

r(t) = normalized value of transient thermal resistance at time, t, i.e.:

Figure 5. Thermal Response

20 k

The temperature of the lead should be measured using a ther-

mocouple placed on the lead as close as possible to the tie point.

The thermal mass connected to the tie point is normally large

enough so that it will not significantly respond to heat surges

generated in the diode as a result of pulsed operation once

steady−state conditions are achieved. Using the measured val-