DATA SHEET
1SMB2EZ11~1SMB2EZ39
GLASS PASSIVATED JUNCTION SILICON ZENER DIODES
2.0 Watts
VOLTAGE
POWER
11 to 39 Volts
FEATURES
• Low profile package
• Built-in strain relief
• Glass passivated iunction
• Low inductance
.083(2.11)
.155(3.94)
.130(3.30)
.075(1.91)
SMB/DO-214AA
Unit: inch (mm)
• Typical I
D
less than 1.0µA above 11V
• Plastic package has Underwriters Laboratory Flammability
Classification 94V-O
• High temperature soldering : 260°C /10 seconds at terminals
• Both normal and Pb free product are available :
.185(4.70)
.160(4.06)
.012(.305)
.006(.152)
.096(2.44)
.083(2.13)
Normal : 80~95% Sn, 5~20% Pb
Pb free: 99% Sn above
MECHANICALDATA
Case: JEDEC
DO-214AA,
Molded plastic over passivated junction
Terminals: Solder plated, solderable per MIL-STD-202G, Method 208
Polarity: Indicated by cathode band
Standard packaging: 12mm tape (EIA-481)
Weight: 0.003 ounce, 0.093 gram
.050(1.27)
.030(0.76)
.008(.203)
.002(.051)
.220(5.59)
.200(5.08)
MAXIMUM RATINGS AND ELECTRICAL CHARACTERISTICS
Ratings at 25°C ambient temperature unless otherwise specified.
Parameter
Pwak Pulse Power Dissipation on TA=50
O
C (Notes A)
Derate above 70
O
C
Peak Forward Surge Current 8.3ms single half sine-wave
superimposed on rated load (JEDEC method)
Operating Junction and Storage Temperature Range
Symbol
Value
3.0
24.0
15
-55 to + 150
Units
W atts
mW/
O
C
Amps
O
P
D
I
FSM
T
J
,T
STG
C
NOTES:
A.Mounted on 5.0mm2 (.013mm thick) land areas.
B.Measured on8.3ms, and single half sine-wave or equivalent square wave ,duty cycle=4 pulses per minute maximum
STAD-NOV.05.2004
PAGE . 1
APPLICATION NOTE:
Since the actual voltage available from a given zener diode is temperature dependent, it is necessary to determinejunction
temperature under any set of operating conditions in order to calculate its value. The following procedure is recommended:
Lead Temperature, T
L
, should be determined from:
T
L
=
q
LA P
D
+ T
A
O
q
L
A
is the lead-to-ambient thermal resistance ( C/W) and Pd is the power dissipation. The value for
q
L
A
will vary and depends
on the device mounting method.
q
L
A
is generally 30-40
O
C/W for the various clips and tie points in common use and for printed
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
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:
T
J
= T
L
+
D
T
JL
D
T
JL
is the increase in junction temperature above the lead temperature and may be found from Figure 2 for a train of power puls
or from Figure 10 for dc power.
D
T
JL
=
q
J
L
P
D
For worst-case design, using expected limits of I
Z
, limits of P
D
and the extremes of T
J
(
D
T
J
) may be estimated. Changes in volta
V
Z
, can then be found from:
D
V =
q
V
Z
D
T
J
q
V
Z
, the zener voltage temperature coefficient, is found from Figures 5 and 6.
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.
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
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.
PAGE . 3
STAD-NOV.05.2004
Embedded System
京公网安备 11010802033920号
EEWORLD
