
Silicon 500 mW Zener Diodes 
Microsemi 
Scottsdale Division 
8700 E. Thomas Rd. PO Box 1390, Scottsdale, AZ 85252 USA, (480) 941-6300, Fax: (480) 947-1503 
Page 1
Copyright 
 2003 
10-31-2003  REV B 
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M
.
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SCOTTSDALE DIVISION
1N957B, -1 thru 1N992B, -1  DO-35 
1
(
DESCRIPTION 
APPEARANCE 
The popular 1N957B thru 1N992B series of 0.5 watt Zener Voltage 
Regulators provides a selection from 6.8 to 200 volts in standard 5% or 
10% tolerances as well as tighter tolerances identified by different suffix 
letters on the part number.  These glass axial-leaded DO-35 Zeners are 
also available with an internal-metallurgical-bond option by adding a “-1” 
suffix.  The 1N962B-1 thru 1N992B-1 are available in JAN, JANTX, and 
JANTXV military qualifications.  Microsemi also offers numerous other 
Zener products to meet higher and lower power applications. 
DO-35 
(DO-204AH)
IMPORTANT:  
For the most current data, consult 
MICROSEMI’s 
 website:  
FEATURES APPLICATIONS / BENEFITS 
 
JEDEC registered 1N957B(-1) to 1N992B(-1) series 
 
Internal metallurgical bond option available by 
adding a “-1” suffix 
 
Also available in JAN, JANTX, and JANTXV 
qualifications per MIL-PRF-19500/117 by adding the 
JAN, JANTX, or JANTXV prefixes to part numbers 
for desired level of screening as well as “-1” suffix; 
(e.g. JANTX1N962B-1, JANTXV1N986C-1, etc.) 
 
Military Surface Mount equivalents also available in 
DO-213AA by adding a UR-1 suffix in addition to the 
JAN, JANTX, and JANTXV prefix; e.g. 
JANTX1N962BUR-1 (see separate data sheet)  
 
Commercial Surface Mount equivalents available as 
MLL957B to MLL992B or with “-1” suffix for bonded 
in the DO-213AA MELF style package (consult 
factory for others) 
 
DO-7 glass body axial-leaded Zener equivalents are 
also available  
MAXIMUM RATINGS 
 
Operating and Storage temperature:  -65
o
C to 
+175
C 
 
Thermal Resistance:  250
 o
C/W junction to lead at 3/8 
(10 mm) lead length from body, or 310
C/W junction 
to ambient when mounted on FR4 PC board (1 oz 
Cu) with 4 mm
 copper pads and track width 1 mm, 
length 25 mm  
 
Steady-State Power:  0.5 watts at T
L
 < 50
o
C 3/8 inch 
(10 mm) from body or 0.48 W at T
A 
< 25
o
C when 
mounted on FR4 PC board as described for thermal 
resistance above (also see Figure1) 
 
Forward voltage @200 mA:  1.1 volts (maximum) for 
1N957B – 1N985B and 1.3 V for 1N985 – 1N992B 
 
Solder Temperatures:  260
 o
C for 10 s (max)  
 
        current and temperature range 
 
Extensive selection from 6.8 to 200 V 
 
Standard voltage tolerances are plus/minus 5% 
        with B suffix, 10 % with A suffix identification 
 
Tight tolerances available in plus or minus 2% 
        or 1% with C or D suffix respectively 
 
Flexible axial-lead mounting terminals 
 
Nonsensitive to ESD per MIL-STD-750 Method 
1020 
 
Minimal capacitance (see Figure 3)
 
Inherently radiation hard as described in 
Microsemi MicroNote 050 
Regulates voltage over a broad operating 
MECHANICAL AND PACKAGING
 
CASE:  Hermetically sealed axial-lead glass       
DO-35 (DO-204AH) package 
 
TERMINALS:  Leads, tin-lead plated solderable 
per MIL-STD-750, method 2026 
 
POLARITY:  Cathode indicated by band.  Diode 
to be operated with the banded end positive 
with respect to the opposite end for Zener 
regulation   
 
MARKING:  Part number  
 
TAPE & REEL option:  Standard per EIA-296 
(add “TR” suffix to part number) 
 
WEIGHT:  0.2 grams 
 
See package dimensions on last page