RATING AND CHARACTERISTICS CURVES
3EZ11 THRU 3EZ200
Fig. 2-TYPICAL THERMAL RESPONSE L
Fig. 3-MAXIMUM SURGE POWER
Fig. 4-TYPICAL REVERSE LEAKAGE
APPLICATION NOTE:
Since the actual voltage available from a given zener
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:
The temperature of the lead can also be measured using
a 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
TL, the junction temperature may be determined by:
TJ = TL + TJL
Lead Temperature, TL, should be determined from:
TL = LAPD + TA
LA is the lead-to-ambient thermal resistance ( /W)
and PD is the power dissipation. The value for LA will
vary and depends on the device mounting method.
LA is generally 30-40 /W for the various chips and
tie points in common use and for printed circuit board
wiring.
TJL is the increase in junction temperature above the
lead temperature and may be found from Figure 2 for a
train of power pulses or from Figure 10 for dc power.
TJL = LAPD
TRSYS [ TRANSYS Electronics Limited ]
