Data Sheet

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
152.0
V
R
, REVERSE VOLTAGE (VOLTS)
115
125
105
304.0
V
R
, REVERSE VOLTAGE (VOLTS)
125
115
105
95
85
75
L, LEAD LENGTH (INCHES)
1/80
25
20
15
10
5.0
0
2/840
T
R
, REFERENCE TEMPERATURE ( C)T
R
JL
, THERMAL RESISTANCE
95
85
75
5.03.0 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
q
JUNCTION-TO-LEAD ( C/W)°
BOTH LEADS TO HEATSINK,
EQUAL LENGTH
MAXIMUM
TYPICAL
, REFERENCE TEMPERATURE ( C)
R
°
R
q
JA
(°C/W) = 70
50
40
28
20
15
10
8.0
15
V
R
, REVERSE VOLTAGE (VOLTS)
115
105
T
R
, REFERENCE TEMPERATURE ( C)
95
85
75
5.03.0 4.0 7.0 10 20
°
R
q
JA
(°C/W) = 70
50
40
28
20
15
10
8.0
125
30
R
q
JA
(°C/W) = 70
50
40
28
20
15
10
8.0
r(t), TRANSIENT THERMAL RESISTANCE
(NORMALIZED)
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″
P
pk
P
pk
t
p
t
1
TIME
DUTY CYCLE = t
p
/t
1
PEAK POWER, P
pk
, is peak of an
equivalent square power pulse.
DT
JL
= P
pk
• R
q
JL
[D + (1 - D) • r(t
1
+ t
p
) + r(t
p
) - r(t
1
)] where:
DT
JL
= the increase in junction temperature above the lead temperature.
r(t) = normalized value of transient thermal resistance at time, t, i.e.:
r(t
1
+ t
p
) = normalized value of transient thermal resistance at time
t
1
+ t
p
, etc.
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
value of T
L
, the junction temperature may be determined by:
T
J
= T
L
+ DT
JL