1N4704 ON Semiconductor, 1N4704 Datasheet - Page 5

• Manufacturer Part Number: 1N4704
• Manufacturer: ON Semiconductor
• Type: Voltage Regulatorr

Specifications of 1N4704

• Number Of Elements: Single
• Package Type: DO-35
• Zener Voltage (typ): 17V
• Voltage Tolerance: 5%
• Operating Temperature Classification: Military
• Rev Curr: 50nA
• Mounting: Through Hole
• Pin Count: 2
• Operating Temp Range: -65C to 200C
• Lead Free Status / Rohs Status: Not Compliant

diode is temperature dependent, it is necessary to determine
junction temperature under any set of operating conditions
in order to calculate its value. The following procedure is
recommended:
is the power dissipation. The value for
depends on the device mounting method.
to 40 C/W for the various clips and tie points in common use
and for printed circuit board wiring.
thermocouple 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
may be determined by:
temperature and may be found from Figure 2 for dc power:
of P
Changes in voltage, V
from Figures 4 and 5.
vary with time and may also be affected significantly by the
zener resistance. For best regulation, keep current
excursions as low as possible.
than would be expected by considering only junction
temperature, as current crowding effects cause temperatures
to be extremely high in small spots, resulting in device
degradation should the limits of Figure 7 be exceeded.
LA
VZ
T
Since the actual voltage available from a given zener
Lead Temperature, T
The temperature of the lead can also be measured using a
For worst-case design, using expected limits of I
Under high power-pulse operation, the zener voltage will
Surge limitations are given in Figure 7. They are lower
JL
, the zener voltage temperature coefficient, is found
is the lead-to-ambient thermal resistance ( C/W) and P
APPLICATION NOTE — ZENER VOLTAGE
D
is the increase in junction temperature above the lead
and the extremes of T
T
T
Z
L
L
, can then be found from:
J
=
T
, should be determined from:
= T
V =
JL
LA
=
L
P
+ T
VZ
D
L
JL
J
, the junction temperature
( T
T
+ T
P
J
JL
D
.
.
A
J
.
) may be estimated.
.
LA
LA
is generally 30
will vary and
Z
1N4678 Series
, limits
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D
5
Figure 2. Typical Thermal Resistance
Figure 3. Typical Leakage Current