1SMB3EZ6-8 PanJit Semiconductors (Pan Jit), 1SMB3EZ6-8 Datasheet - Page 3

• Manufacturer Part Number: 1SMB3EZ6-8
• Description: Silicon Zener Diodes
• Manufacturer: PanJit Semiconductors (Pan Jit)

REV.0-JUN.15.2005
APPLICATION NOTE:
temperature under any set of operating conditions in order to calculate its value. The following procedure is recommended:
generated in the diode as a result of pulsed operation once steady-state conditions are achieved. Using the measured value of
TL, the junction temperature may be determined by:
D
or from Figure 10 for dc power.
V , can then be found from:
Under high power-pulse operation, the zener voltage will vary with time and may also be affected significantly by the zener resis
For best regulation, keep current excursions as low as possible.
be expected by considering only junction temperature, as current crowding effects cause temperatures to be extremely high in s
spots resulting in device degradation should the limits of Figure 3 be exceeded.
1SMB3EZ6.8~1SMB3EZ100
Since the actual voltage available from a given zener diode is temperature dependent, it is necessary to determinejunction
The thermal mass connected to the tie point is normally large enough so that it will not significantly respond to heat surges
For worst-case design, using expected limits of I , limits of P and the extremes of T ( T ) may be estimated. Changes in volta
q
Data of Figure 2 should not be used to compute surge capa-bility. Surge limitations are given in Figure 3. They are lower than w
T
Z
on the device mounting method.
circuit board wiring.
The temperature of the lead can also be measured using a thermocouple placed on the lead as close as possible to the tie poin
Lead Temperature, T , should be determined from:
q
V , the zener voltage temperature coefficient, is found from Figures 5 and 6.
JL
L is the lead-to-ambient thermal resistance ( C/W) and Pd is the power dissipation. The value for L will vary and depends
Z
A
is the increase in junction temperature above the lead temperature and may be found from Figure 2 for a train of power puls
L
q
L is generally 30-40 C/W for the various clips and tie points in common use and for printed
A
O
Z
T = T + T
D
D
T
V = V
J
T = LA P + T
JL
L
= J P
q
L
q
q
O
Z
D
L
D
T
D
D
JL
J
D
A
J
D
J
q
A
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