13-3
High Reliability Varistors
High Reliability Series Mechanical and
Environmental Testing for Aerospace,
Military and High Reliability Applications
The high reliability Harris varistor is the latest step in
increased product performance, and is available for
applications requiring quality and reliability assurance levels
consistent with military or other standards. (MIL-STD-19500,
MIL-S-750, Method 202). Additionally, Harris varistors are
inherently radiation hardened compared to silicon diode
suppressors as illustrated in Figure 1.
This series of high-reliability varistors involve five categories:
• DESC Qualified Parts List (QPL) MIL-R-83530
4 types presently available
• DESC Standard Military Drawings based on MIL-R-83530
63 types presently available:
- ZA Series - Drawing #87063
- DB Series - Drawing #90065
• Harris high reliability series offers TX equivalents
29 types presently available
• Custom types processed to customer-specific require-
ments - (SCD) or to standard military flow
• SP720 - High Reliability Electronic Protection Array
Credentials
Harris varistors and quality management systems are:
• DESC approved
• QPL listed
• CECC approved
• ISO approved
• UL approved
• CSA approved
DESC Qualified Parts List (QPL) MIL-R-83530
TABLE 1. MIL-R-83530/1 RATINGS AND CHARACTERISTICS
PART
NUMBER
M83530/
NOMINAL
VARISTOR
VOLTAGE
(V) TOLERANCE
(%)
VOLTAGE
RATING
(V) ENERGY
RATING
(J)
CLAMPING
VOLTAGE
AT 100A
(V)
CAPACITANCE
AT 1MHz
(pF)
CLAMPING
VOLTAGE
AT PEAK
CURRENT
RATING
(V) ITM
(A)
NEAREST
COMMERCIAL
EQUIVALENT(RMS) (DC)
1-2000B 200 ±10 130 175 50 325 3800 570 6000 V130LA20B
1-2200D 220 +10, -5 150 200 55 360 3200 650 6000 V150LA20B
1-4300E 430 +5, -10 275 369 100 680 1800 1200 6000 V275LA40B
1-5100E 510 +5, -10 320 420 120 810 1500 1450 6000 V320LA40B
This series of varistors are screened and conditioned in accordance with MIL-R-83530 as outlined in Table 2. Manufacturing system con-
forms to MIL-I-45208; MIL-Q-9858.
13-4
High Reliability Series
MIL-R-83530 Inspections
TABLE 2. MIL-R-83530 GROUP A, B, AND C INSPECTIONS
INSPECTION
AQL
(PERCENT
DEFECTIVE) MAJOR MINOR NUMBER OF
SAMPLE UNITS FAILURES
ALLOWED
Group A SUBGROUP 1
High Temperature Life (Stabilization Bake) 100% - - - -
Thermal Shock 100% - - - -
Power Burn-In 100% - - - -
Clamping Voltage 100% - - - -
Nominal Varistor Voltage 100% - - - -
SUBGROUP 2
Visual and Mechanical Examination - 1.0% AQL
7.6% LQ 25% AQL
13.0% LQ Per Plan -
Body Dimensions - Per Plan -
Diameter and Length of Leads - Per Plan -
Marking - Per Plan -
Workmanship - Per Plan -
SUBGROUP 3
Solderability - - - Per Plan -
Group B SUBGROUP 1
Dielectric Withstanding Voltage - - - Per Plan -
SUBGROUP 2
Resistance to Solvents - - - Per Plan -
SUBGROUP 3
Terminal Strength (Lead Fatigue) - - - Per Plan -
Moisture Resistance - - - Per Plan -
Peak Current - - - Per Plan -
Energy - - - Per Plan -
Group C EVERY 3 MONTHS
High Temperature Storage - - - 10 0
Operating Life (Steady State) - - - 10 0
Pulse Life - - - 10 0
Shock - - - 10 0
Vibration - - - 10 0
Constant Acceleration - - - 10 0
Energy - - - 10 0
13-5
High Reliability Series
DESC Standard Military Drawing # 87063
Based on MIL-R-83530
TABLE 3. ZA SERIES RATINGS AND SPECIFICATIONS
87063
DASH
NO.
NEAREST
COMM.
NO. (NOTE 1)
SIZE
MAXIMUM RATINGS (+85oC) SPECIFICATIONS (+25oC)
CONTINUOUS TRANSIENT
VARISTOR VOLTAGE
AT 1mADC
TEST CURRENT
MAXIMUM
CLAMPING
VOLTAGE
VC AT TEST
CURRENT
(8/20µs) TYPICAL
CAPACITANCERMS DC
ENERGY
(10/
1000µs)
PEAK
CURRENT
(8/20µs)
VM(AC) VM(DC) WTM ITM MIN VN(DC) MAX VCICf = 1MHz
(V) (V) (J) (A) (V) (V) (V) (V) (A) (pF)
001 V22ZA05 1 14 18 0.2 35 18.7 22 26 51 2 400
002 V22ZA1 2 14 18 0.9 150 18.7 22 26 47 5 1600
003 V22ZA2 3 14 18 2.0 350 18.7 22 26 43 5 4000
004 V22ZA3 4 14 18 4.0 750 18.7 22 26 43 10 9000
005 V24ZA50 5 14 18 6.5 1500 19.2 24
(Note 2) 26 43 20 18000
006 V27ZA05 1 17 22 0.25 35 23 27 31.1 59 2 300
007 V27ZA1 2 17 22 1.0 150 23 27 31.1 57 5 1300
008 V27ZA2 3 17 22 2.5 350 23 27 31.1 53 5 3000
009 V27ZA4 4 17 22 5.0 750 23 27 31.1 53 10 7000
010 V27ZA60 5 17 22 8.0 1500 23 27
(Note 2) 31.1 50 20 15000
011 V33ZA05 1 20 26 0.3 35 29.5 33 38 67 2 250
012 V33ZA1 2 20 26 1.2 150 29.5 33 36.5 68 5 1100
013 V33ZA2 3 20 26 3.0 350 29.5 33 36.5 64 5 2700
014 V33ZA5 4 20 26 6.0 750 29.5 33 36.5 64 10 6000
015 V33ZA70 5 21 27 9.0 1500 29.5 33
(Note 2) 36.5 58 20 13000
016 V36ZA80 5 23 31 10.0 1500 32 36
(Note 2) 40 63 20 12000
017 V39ZA05 1 25 31 0.35 35 35 39 46 79 2 220
018 V39ZA1 2 25 31 1.5 150 35 39 43 79 5 900
019 V39ZA3 3 25 31 3.5 350 35 39 43 76 5 2200
020 V39ZA6 4 25 31 7.2 750 35 39 43 76 10 5000
021 V47ZA05 1 30 38 0.4 35 42 47 55 90 2 200
022 V47ZA1 2 30 38 1.8 150 42 47 52 92 5 800
023 V47ZA3 3 30 38 4.5 350 42 47 52 89 5 2000
024 V47ZA7 4 30 38 8.8 750 42 47 52 89 10 4500
025 V56ZA05 1 35 45 0.5 35 50 56 66 108 2 180
13-6
High Reliability Series
026 V56ZA2 2 35 45 2.3 150 50 56 62 107 5 700
027 V56ZA3 3 35 45 5.5 350 50 56 62 103 5 1800
028 V56ZA8 4 35 45 10.0 750 50 56 62 103 10 3900
029 V68ZA05 1 40 56 0.6 35 61 68 80 127 2 150
030 V68ZA2 2 40 56 3.0 150 61 68 75 127 5 600
031 V68ZA3 3 40 56 6.5 350 61 68 75 123 5 1500
032 V68ZA10 4 40 56 13.0 750 61 68 75 123 10 3300
033 V82ZA05 1 50 66 1.2 70 73 82 97 145 2 120
034 V82ZA2 2 50 66 3.5 300 73 82 91 135 10 500
035 V82ZA4 3 50 66 7.3 750 73 82 91 135 25 1100
036 V82ZA12 4 50 66 13.0 1500 73 82 91 145 50 2500
037 V100ZA05 1 60 81 1.5 70 90 100 117 175 2 90
038 V100ZA3 2 60 81 4.3 300 90 100 110 165 10 400
039 V100ZA4 3 60 81 8.9 750 90 100 110 165 25 900
040 V100ZA15 4 60 81 16.0 1500 90 100 110 175 50 2000
041 V120ZA05 1 75 102 1.8 100 108 120 138 205 2 70
042 V120ZA1 2 75 102 5.3 400 108 120 132 205 10 300
043 V120ZA4 3 75 102 11.0 1000 108 120 132 200 25 750
044 V120ZA6 4 75 102 19.0 2000 108 120 132 210 50 1700
045 V150ZA05 1 92 127 2.3 100 135 150 173 240 2 60
046 V150ZA1 2 95 127 6.5 400 135 150 165 250 10 250
047 V150ZA4 3 95 127 13.0 1000 135 150 165 250 25 600
048 V150ZA8 4 95 127 23.0 2000 135 150 165 255 50 1400
049 V180ZA05 1 110 153 2.7 150 162 180 207 290 2 50
050 V180ZA1 2 115 153 7.7 500 162 180 198 295 10 200
051 V180ZA5 3 115 153 16.0 1500 162 180 198 300 25 500
052 V180ZA10 4 115 153 27.0 3000 162 180 198 300 50 1100
NOTES:
1. Size 1-5mm, 2-7mm, 3-10mm, 4-14mm, 5-20mm
2. 10mA DC test current.
TABLE 3. ZA SERIES RATINGS AND SPECIFICATIONS (Continued)
87063
DASH
NO.
NEAREST
COMM.
NO. (NOTE 1)
SIZE
MAXIMUM RATINGS (+85oC) SPECIFICATIONS (+25oC)
CONTINUOUS TRANSIENT
VARISTOR VOLTAGE
AT 1mADC
TEST CURRENT
MAXIMUM
CLAMPING
VOLTAGE
VC AT TEST
CURRENT
(8/20µs) TYPICAL
CAPACITANCERMS DC
ENERGY
(10/
1000µs)
PEAK
CURRENT
(8/20µs)
VM(AC) VM(DC) WTM ITM MIN VN(DC) MAX VCICf = 1MHz
(V) (V) (J) (A) (V) (V) (V) (V) (A) (pF)
13-7
High Reliability Series
DESC Standard Military Drawing # 90065
Based on MIL-R-83530
Harris High Reliability Series TX Equivalents
TABLE 5. AVAILABLE TX MODEL TYPES
TABLE 4. DB SERIES RATINGS AND SPECIFICATIONS
90065
DASH
NO.
VOLTAGE
RATING
MAX.
(RMS)
ENERGY
MAX
(J)
PEAK
CURRENT
(A)
NOMINAL
VARISTOR
VOLTAGE
(V)
MAX CLAMPING
VOLTAGE AT
TEST CURRENT TYPICAL
CAPACITANCE
(pF)(V) (I)
012 130 170 22500 200 +28, -16 345 200 10000
013 150 200 22500 240 ±28 405 200 8000
014 250 270 22500 390 +39, -36 650 200 5000
015 275 300 22500 430 ±43 730 200 4500
016 320 350 22500 510 +29, -48 830 200 3800
017 420 460 28800 680 +68, -70 1130 200 3000
018 480 510 28800 750 +74, -80 1240 200 2700
019 510 550 28800 820 +91, -85 1350 200 2500
020 575 600 28800 910 +95, -105 1480 200 2200
021 660 690 28800 1050 ±110 1720 200 2000
022 750 810 28800 1200 ±120 2000 200 1800
TX MODEL MODEL
SIZE DEVICE
MARK
NEAREST
COMMERCIAL
EQUIVALENT
V8ZTX1 7mm 8TX1 V8ZA1
V8ZTX2 10mm 8TX2 V8ZA2
V12ZTX1 7mm 12TX1 V12ZA1
V12ZTX2 10mm 12TX2 V12ZA2
V22ZTX1 7mm 22TX1 V22ZA1
V22ZTX3 14mm 22TX3 V22ZA3
V24ZTX50 20mm 24TX50 V24ZA50
V33ZTX1 7mm 33TX1 V33ZA1
V33ZTX5 14mm 33TX5 V33ZA5
V33ZTX70 20mm 33TX70 V33ZA70
V68ZTX2 7mm 68TX2 V68ZA2
V68ZTX10 14mm 68TX10 V68ZA10
V82ZTX2 7mm 82TX2 V82ZA2
V82ZTX12 14mm 82TX12 V82ZA12
V130LTX2 7mm 130TX V130LA2
V130LTX10A 14mm 130TX10 V130LA10A
V130LTX20B 20mm 130TX20 V130LA20A
V150LTX2 7mm 150TX V150LA2
V150LTX10A 14mm 150TX10 V150LA10A
V150LTX20B 20mm 150TX20 V150LA20B
V250LTX4 7mm 250TX V250LA4
V250LTX20A 14mm 250TX20 V250LA20A
V250LTX40B 20mm 250TX40 V250LA40B
V420LTX20A 14mm 420TX20 V420LA20A
V420LTX40B 20mm 420TX40 V420LA40B
V480LTX40A 14mm 480TX40 V480LA40A
V480LTX80B 20mm 480TX80 V480LA80B
V510LTX40A 14mm 510TX40 V510LA40A
V510LTX80B 20mm 510TX80 V510LA80B
TX MODEL MODEL
SIZE DEVICE
MARK
NEAREST
COMMERCIAL
EQUIVALENT
13-8
High Reliability Series
The TX series of varistors are 100% screened and conditioned in accordance with MIL-STD-750. Tests are as outlined in
Table 6.
TABLE 6. TX EQUIVALENTS SERIES 100% SCREENING
SCREEN MIL-STD-750
METHOD CONDITION TX
REQUIREMENTS
High Temperature Life
(stabilization bake) 1032 24 hours min. at max. rated storage temperature. 100%
Thermal Shock
(temperature cycling) 1051 No dwell is required at 25oC. Test condition A1, 5 cycles
-55oC to +125 oC (extremes). >10 minutes 100%
Humidity Life 85oC, 85% R.H., 168 hours. 100%
Interim Electrical VN(DC) VC
(Note 1) As specified, but including delta parameter as a mini-
mum. 100% Screen
Power Burn-In 1038 Condition B, 85oC, Rated VM(AC), 72 hours min 100%
Final Electrical +VN(DC) VC
(Note 1) As specified — All parameter measurements must be
completed within 96 hours after removal from burn-in
conditions.
100% Screen
External Visual Examination 2071 To be performed after complete marking. 100%
NOTE:
1. Delta Parameter - VN(DC)
Maximum allowable shift ±10% Max.
Applicable lot PDA - 10% Max.
Peak current and energy ratings are derated by 10% and 30%, respectively, from standard parts.
TABLE 7. QUALITY ASSURANCE ACCEPTANCE TEST
MIL-STD-105
LTPDLEVEL AQL
Electrical (Bidirectional)
VN(DC), VC (Per specifications table) II 0.1 -
Dielectric Withstand Voltage
MIL-STD-202, Method 301, 2500V min. at 1.0µADC
--15
Solderability
MIL-STD-202, Method 208, no aging, non-activated --15
INSPECTION LOTS
FORMED AFTER
ASSEMBLY
LOTS PROPOSED
FOR TX TYPES 100% SCREENING
REVIEW OF DATA
TX PREPARATION
FOR DELIVERY
QA ACCEPTANCE
SAMPLE PER
APPLICABLE DEVICE
SPECIFICATION
13-9
High Reliability Series
TABLE 8. MECHANICAL AND ENVIRONMENTAL CAPABILITIES (TYPICAL CONDITIONS)
TEST NAME TEST METHOD DESCRIPTION
Terminal Strength MIL-STD-750-2036 3 Bends, 90o Arc, 16oz. Weight
Drop Shock MIL-STD-750-2016 1500g's, 0.5ms, 5 Pulses, X1, V1, Z1
Variable Frequency Vibration MIL-STD-750-2056 20g's, 100-2000Hz, X1, V1, Z1
Constant Acceleration MIL-STD-750-2006 V2, 20,000g's Min
Salt Atmosphere MIL-STD-750-1041 35oC, 24 hrs, 10-50g/m2 Day
Soldering Heat/Solderability MIL-STD-750-2031/2026 260oC, 10s, 3 Cycles, Test Marking
Resistance to Solvents MIL-STD-202-215 Permanence, 3 Solvents
Flammability MIL-STD-202-111 15s Torching, 10s to Flameout
Flammability UL1414 3 x 15s Torching
Cyclical Moisture Resistance MIL-STD-202-106 10 Days
Steady-State Moisture Resistance 85/85 96 Hrs.
Biased Moisture Resistance Not Recommended for High-Voltage Types
Temperature Cycle MIL-STD-202-107 -55oC to +125oC, 5 Cycles
High-Temperature Life (Nonoperating) MIL-STD-750-1032 125oC, 24 Hrs.
Burn-In MIL-STD-750-1038 Rated Temperature and VRMS
Hermetic Seal MIL-STD-750-1071 Condition D
Custom Types
In addition to our comprehensive high-reliability series as
referenced above, Harris can screen and condition to
customer-specific requirements.
Additional mechanical and environmental capabilities are
defined in Table 8.
Radiation Hardness
For space applications, an extremely important property of a
protection device is its response to imposed radiation
effects.
Electron Irradiation
A Harris MOV and a silicon transient suppression diode
were exposed to electron irradiation. The V-I Curves, before
and after test, are shown in Figure 1.
It is apparent that the Harris MOV was virtually unaffected,
even at the extremely high dose of 108 rads, while the silicon
transient suppression diode showed a dramatic increase in
leakage current.
FIGURE 1. RADIATION SENSITIVITY OF HARRIS V130LA1
AND SILICON TRANSIENT SUPPRESSION DIODE
V
200
100
80
60
40
20108106104102
SILICON
TRANSIENT
CURRENT (A)
PRE TEST
108 RADS,
18MeV ELECTRONS
HARRIS MOV
SUPPRESSION
DIODE
13-10
High Reliability Series
Neutron Effects
A second MOV-Zener comparison was made in response to
neutron fluence. The selected devices were equal in area.
Figure 2 shows the clamping voltage response of the
MOV and the zener to neutron irradiation to as high as
1015 N/cm2. It is apparent that in contrast to the large
change in the zener, the MOV is unaltered. At higher cur-
rents where the MOV's clamping voltage is again
unchanged, the zener device clamping voltage increases by
as much as 36%.
FIGURE 2. V-I CHARACTERISTIC RESPONSE TO NEUTRON
IRRADIATION FOR MOV AND ZENER DIODE
DEVICES
Counterclockwise rotation of the V-I characteristics is
observed in silicon devices at high neutron irradiation levels;
in other words, increasing leakage at low current levels and
increasing clamping voltage at higher current levels.
The solid and open circles for a given fluence represent the
high and low breakdown currents for the sample of devices
tested. Note that there is a marked decrease in current (or
energy) handling capability with increased neutron fluence.
Failure threshold of silicon semiconductor junctions is further
reduced when high or rapidly increasing currents are
applied. Junctions develop hot spots, which enlarge until a
short occurs if current is not limited or quickly removed.
VOLTS
200
100
80
60
40
20
108
10 107106104103
AMPERES
300
50
30
10 10 105
1.5K 200
AT 1015
1.5K 200 INITIAL
VARISTOR V130A2
INITIAL AT 1015
1.5K 200
AT 1014
1.5K 200
AT 1013
1.5K 200
AT 1012
The characteristic voltage current relationship of a PN-Junc-
tion is shown in Figure 3.
FIGURE 3. V-I CHARACTERISTIC OF PN-JUNCTION
At low reverse voltage, the device will conduct very little
current (the saturation current). At higher reverse voltage
VBO (breakdown voltage), the current increases rapidly as
the electrons are either pulled by the electric field (Zener
effect) or knocked out by other electrons (avalanching). A
further increase in voltage causes the device to exhibit a
negative resistance characteristic leading to secondary
breakdown.
This manifests itself through the formation of hotspots, and
irreversible damage occurs. This failure threshold decreases
under neutron irradiation for zeners, but not for Zinc Oxide
Varistors.
Gamma Radiation
Radiation damage studies were performed on type V130LA2
varistors. Emission spectra and V-I characteristics were
collected before and after irradiation with 106 rads Co60
gamma radiation.
Both show no change, within experimental error, after
irradiation.
SATURATION
CURRENT
BREAKDOWN
VOLTAGE
I
V
REDUCTION IN
FAILURE STRESSHOLD
BY RADIAL
SECONDARY
BREAKDOWN
REVERSE
BIAS
FORWARD
BIAS
