DC Application Varistor Design Guide

AUMOV® & LV UltraMOV™ Varistor Design
Guide for DC & Automotive Applications
High Surge
Current Varistors
Design Guide for
Automotive AUMOV®
Varistor & LV UltraMOV™
Varistor Series
Table of Contents
Page
About the AUMOV® Varistor Series
3-4
About the LV UltraMOV Series Varistor
5-6
™
Varistor Basic
6
Terminology Used in Varistor Specifications
7
Automotive MOV Background and Application Examples
8-10
LV UltraMOV™ Varistor Application Examples
11-12
How to Select a Low Voltage DC MOV
13-15
Transient Suppression Techniques
16-17
Introduction to Metal Oxide Varistors (MOVs)
Series and Parallel Operation of Varistors
18
19-20
AUMOV® Varistor Series Specifications and Part Number Cross-References
21-22
LV UltraMOV™ Series Specifications and Part Number Cross-References
23-26
Legal Disclaimers
27
© 2015 Littelfuse, Inc.
Specifications descriptions and illustrative material in this literature are as accurate as known at the time of publication,
but are subject to changes without notice. Visit littelfuse.com for more information.
DC Application Varistor Design Guide
About the AUMOV® Varistor Series
About the AUMOV® Varistor Series
The AUMOV® Varistor Series is designed for circuit protection in low voltage (12VDC,
24VDC and 42VDC) automotive systems. This series is available in five disc sizes with
radial leads with a choice of epoxy or phenolic coatings. The Automotive MOV Varistor is
AEC-Q200 (Table 10) compliant. It offers robust load dump, jump start, and peak surge
current ratings, as well as high energy absorption capabilities.
These devices are available in these sizes and ratings:
• Disc sizes: 5mm, 7mm, 10mm, 14mm, 20mm
• Operating Voltage Ratings: 16–50VDC
• Surge Current Ratings: 400–5000A (8/20μs)
• Jump Start Ratings: 6–100 Joules
• Load Dump Ratings: 25–35 VJump
AUMOV® Varistor Series Features
• AEC–Q200 (Table 10) compliant
• Robust load dump and jump start ratings
• High operating temperature: up to 125°C (phenolic coating option)
• High peak surge current rating and energy absorption capability
AUMOV® Varistor Series Benefits
• Meets requirements of the automotive industry
• Complies with ISO 7637-2
• Offers options suitable for higher temperature environments and applications
• Enhances product safety as a result of superior surge protection and energy absorption
• ISO/TS 16949 Certified manufacturing facilities
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DC Application Varistor Design Guide
About the AUMOV® Varistor Series (continued)
AUMOV® Varistor Series Applications
The AUMOV® Varistor Series is well suited for circuit protection in a variety of automotive
electronics applications, including electronic modules designed for safety systems, body
electronics, powertrain systems, heating/ventilation/air-conditioning control, navigation,
center console, and infotainment systems.
Automotive MOV Series Part Numbering System
AUMOV® Varistor Series Part Numbering System
V 05 E 14 AUTO L1 B XXXXX
Littelfuse “Varistor”:
Other Non-Standard Options
Disc Size:
5 to 20mm
Packaging:
Blank or
B: Bulk Pack
T: Tape and Reel
A: Ammo Pack
Coating:
E = Epoxy
P = Phenolic
VM(AC)RMS:
14V to 42V
Lead Formation:
Blank or
L1: Straight
L2: Crimped
L3: In-Line
L4: Trim/Crimp (Bulk pack only)
Automotive Series:
Lead-Free, RoHS and
Halogen Free Compliant
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DC Application Varistor Design Guide
About the LV UltraMOV™
About the LV UltraMOV™ Varistor Series
The LV UltraMOV ™ Varistor Low Voltage, High Surge Current Varistor Series provides an
ideal circuit protection solution for lower DC voltage applications by offering a superior
surge rating in a smaller disc size. The maximum peak surge current rating can reach
up to 10kA (8/20µs pulse) to protect against high peak surges, including lightning strike
interference, electrical fast transients on power lines, and inductive spikes in industrial
applications.
These devices are available in these sizes and voltage ranges:
• Disc Diameter: 5mm, 7mm, 10mm, 14mm and 20mm
• Maximum Continuous Voltage (VDC): 14V to 125V
• Varistor Voltage (Vnom) at 1m A: 18V to 150V
LV UltraMOV™ Varistor Series Features
• Breakthrough in low voltage varistor design provides high peak surge current rating
• Reduced footprint and volume required for surge protection
• High energy absorption capability
• High resistance to temperature cycling
• Optional phenolic coating
• Lead-free, halogen-free, and RoHS compliant
LV UltraMOV™ Varistor Series Benefits
• Increased long-term reliability due to the ability to handle higher surges over the end
product’s lifetime
• More board space is available for higher value functional components
• Lower weight and cost for end product from use of a smaller disc
• Higher surge handling density in critical surge protection device module solutions
• Higher operating temperature range—up to 125°C
• Environmentally friendly product
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DC Application Varistor Design Guide
About the LV UltraMOV™ and Varistor Basics
Enhanced protection level—Higher surge withstanding and longer life
An LV UltraMOV ™ Varistor can withstand higher surge current/energy and more surge
strikes than the same size varistor from the standard Littelfuse series. For example, a
new 10mm LV UltraMOV ™ Varistor is rated at 2000A max. surge current, which is four
times higher than a standard one. The higher surge rating also can provide longer life and
reliability because there will be less degradation of the MOV over its lifetime.
Reduced component size—More compact designs
An LV UltraMOV ™ Varistor is smaller than a standard Littelfuse varistor with the same
surge capability. This reduces both PCB space requirements and component height.
For example, an ordinary 10mm MOV capable of 500A maximum surge current could
be replaced by a new 5mm LV UltraMOV ™ Varistor with the same 500A surge rating;
MOV size is reduced from 10mm to 5mm and mounting height is reduced from
14mm to 10mm.
Higher operating temperature range
An LV UltraMOV ™ Varistor with the phenolic coating option can be operated in
environments up to 125°C, making it suitable for use in more severe conditions such as
industrial applications.
Varistor Basics
Varistors are voltage dependent, nonlinear devices that behave electrically similar to
back-to-back Zener diodes. The symmetrical, sharp breakdown characteristics shown
here enable the varistor to provide excellent transient suppression performance. When
exposed to high voltage transients, the varistor impedance changes many orders of
magnitude—from a near open-circuit to a highly conductive level—thereby clamping
the transient voltage to a safe level. The potentially destructive energy of the incoming
transient pulse is absorbed by the varistor, thereby protecting vulnerable circuit
components.
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DC Application Varistor Design Guide
Terminology Used in Varistor Specifications
Terminology Used in Varistor Specifications
Terms and Descriptions
Symbol
Clamping Voltage. Peak voltage across the varistor measured under conditions of a specified peak
VC pulse current and specified waveform. NOTE: Peak voltage and peak currents are not necessarily
coincidental in time.
VC
Rated Peak Single-Pulse Transient Currents. Maximum peak current which may be applied for a
single 8/20μs impulse, with rated line voltage also applied, without causing device failure.
I TM
Lifetime Rated Pulse Currents. Derated values of I TM for impulse durations exceeding that of an
8/20μs waveshape, and for multiple pulses which may be applied over device rated lifetime.
-
Rated RMS Voltage. Maximum continuous sinusoidal RMS voltage which may be applied.
V M(AC)
Rated DC Voltage. Maximum continuous DC voltage which may be applied.
V M(DC)
DC Standby Current. Varistor current measured at rated voltage, V M(DC).
ID
For certain applications, some of the following terms may be useful.
Nominal Varistor Voltage. Voltage across the varistor measured at a specified pulsed DC current,
IN(DC), of specific duration. IN(DC) is specified by the varistor manufacturer.
V N(DC)
Peak Nominal Varistor Voltage. Voltage across the varistor measured at a specified peak AC current,
IN(AC), of specific duration. IN(AC) is specified by the varistor manufacturer.
V N(AC)
Rated Recurrent Peak Voltage. Maximum recurrent peak voltage which may be applied for a
specified duty cycle and waveform.
V PM
Rated Single-Pulse Transient Energy. Energy which may be dissipated for a single impulse of
maximum rated current at a specified waveshape, with rated RMS voltage or rated DC voltage also
applied, without causing device failure.
W TM
Rated Transient Average Power Dissipation. Maximum average power which may be dissipated due
to a group of pulses occurring within a specified isolated time period, without causing device failure.
Varistor Voltage. Voltage across the varistor measured at a given current, I X .
VX
Voltage Clamping Ratio. A figure of merit measure of the varistor clamping effectiveness as defined
by the symbols (VC) ÷ (V M(AC)), (VC) ÷ (V M(DC)).
VC /V PM
Nonlinear Exponent. A measure of varistor nonlinearity between two given operating currents, I1 and
I2 , as described by I = kVa where k is a device constant, I1 ≤ I ≤ I2 , and a12 = ( logI2 / I1 ) ÷ ( logV 2 / V1 )
a
Dynamic Impedance. A measure of small signal impedance at a given operating point as defined by:
Z X = ( dV X ) ÷ ( dI X )
ZX
Resistance (Varistor). Static resistance of the varistor at a given operating point as defined by:
R X = ( V X) ÷ ( IX)
RX
Capacitance (Varistor). Capacitance between the two terminals of the varistor measured at specified
frequency and bias.
CX
AC Standby Power. Varistor AC power dissipation measured at rated RMS voltage V M(AC).
PD
Voltage Overshoot. The excess voltage above the clamping voltage of the device for a given current
that occurs when current waves of less than 8μs virtual front duration are applied. This value may be
expressed as a % of the clamping voltage (VC) for an 8/20µs current wave.
VOS
Response Time. The time between the point at which the wave exceeds the clamping voltage level
(VC) and the peak of the voltage overshoot. For the purpose of this definition, clamping voltage as
defined with an 8/20μs current waveform of the same peak current amplitude as the waveform used
for this response time.
-
Overshoot Duration (Varistor). The time between the point at voltage level (VC) and the point at which
the voltage overshoot has decayed to 50% of its peak. For the purpose of this definition, clamping
voltage is defined with an 8/20μs current waveform of the same peak current amplitude as the
waveform used for this overshoot duration.
-
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DC Application Varistor Design Guide
Automotive MOV Background and Application Examples
Threats on Low Voltage Line
Automotive MOV Background and Application Examples
Threats on Low Voltage Line
120V Load Dump
85V Noise
24V Jump Start
Norminal
14V
6V Crank
Reverse
Battery
Automotive EMC transient requirements from ISO 7637:
Pulse 1
Interruption of inductive load – refers to disconnection of the power
supply from an inductive load while the device under test (DUT) is in
parallel with the inductive load
Pulse 2
Interruption of series inductive load – refers to the interruption of
current and causes load switching
Pulse 3
Switching spikes
3a negative transient burst
3b positive transient burst
Refers to the unwanted transients in the switching events
Pulse 4
Starter crank – refers battery voltage drop during motor start. This
always happens in cold weather
Pulse 5
Load dump – refers to the battery being disconnected when it is
charged by the alternator.
Pulse 6
Ignition coil interruption
Pulse 7
Alternator field decay
Related to high voltage transient getting into the supply line; Pulse 4
Pulses 1, 2, 3a, 3b, 5, 6, 7 defines minimum battery voltage.
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DC Application Varistor Design Guide
Automotive MOV Background and Application Examples (continued)
Load Dump
Load dump is what happens to the supply voltage in a vehicle when a load is removed.
If a load is removed rapidly (such as when the battery is disconnected while the engine
is running), the voltage may spike before stabilizing, which can damage electronic
components. In a typical 12V circuit, load dump can rise as high as 120V and take as long as
400 milliseconds to decay—more than enough time to cause serious damage.
T
V
T1
90%
VS
10%
VB
t
T1 = 5ms to 10ms
T = 40ms to 400ms
VS= 25V to 125V
VB = 14V
Load dump waveform (from ISO 7637)
Load Dump Transient
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DC Application Varistor Design Guide
Automotive MOV Background and Application Examples (continued)
Automotive Applications
System Protection against Alternator Transients
System Protection against Alternator Transients
The alternator causes most
of the transients in a vehicle’s
electrical system.
Alternator
Wipers
Airbag
Littelfuse automotive MOVs
can be connected in a Y or Delta
configuration with the winding
coil of the alternator to clamp
the transients.
+
BATT
ABS
Air Condition
Voltage Reg.
Window
Motor
Vehicle subsystem module transient protection
Vehicle subsystem module transient protection
Vehicles subsystems such
as the ECU, airbag, etc.
can be damaged by the
transient caused when the
alternator provides power to
the electronics.
Littelfuse automotive MOVs
can be used as a shunt for
the transient surge for the DC
power line.
Voltage Reg.
Protected
System
Alternator
ECU
Airbag
Motor
Infotainment
Etc.
Automotive Relay Surge Protection
Automotive Relay Surge Protection
Typical relay operation would
generate arcing during the
switch of the relay contacts,
thereby damaging the IC and
other sensitive electronic
devices. Littelfuse automotive
MOVs will absorb the arcing
energy released from the
magnetic fields of the relay.
Relay
Coil
Protected
System
Starter
Lights
Speaker
Etc.
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DC Application Varistor Design Guide
LV UltraMOV™ Varistor Application Examples
LV UltraMOV™ Varistor Application Examples
A variety of applications employ 12VDC–96VDC circuits, including telecom power, sensing,
automation, control, and security systems. Transients on these lines can be caused by
lightning interference, inductive spikes from power switching, and fast transients from
induced power line fluctuations. For example, a relay switching on/off can cause a magnetic
transient in the coil inductance, which produces a high voltage spike.
Compared with the other clamping and crowbar technologies that are used for voltage
suppression, varistor technology is still one of the most cost-effective ways to protect
against high energy surges on these 12VDC–96VDC lines.
LV UltraMOV ™ Varistors are widely used in a number of application areas:
Clamping Lightning-induced Transients in Power Supplies
Most transients induced
by nearby lightning strikes
result in an electromagnetic
disturbance on electrical and
communication lines connected
to electronic equipment.
Inductive Load Switching
Switching of inductive loads,
such as those that occur with
transformers, generators,
motors and relays, can create
transients up to hundreds of
volts and amps, and can last as
long as 400 milliseconds.
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DC Application Varistor Design Guide
LV UltraMOV™ Varistor Application Examples (continued)
Telecom/SPD
Application
Telecom/SPD Application
+
Telecom Power Supply Units
(PSUs) typically range from
36VDC to 72VDC on the high
end of the voltage range. The LV
UltraMOV™ varistor can be used
for applications where the voltage
is less than 125VDC. Low Voltage
Surge Protective Device (SPD)
modules are used in telecom and
industrial applications to provide
module-based surge protection of
complete systems.
-
In telecom power applications, multiple LV UltraMOVTM varistors are used in a single
SPD to provide surge protection. Several varistors are connected in parallel to provide
the desired level of energy handling. The varistors are connected in series with a GDT to
provide additional transient protection to earth/ground. Outdoor Low Voltage Application
12VAC/DC and 24VAC/VDC are
System/LED
Protection
the voltages commonly used for Security
Outdoor
Low Voltage
Application
security system components
12V/24V
such as motion sensors, IP
AC/DC Input
cameras, and DVRs.
Load
Demand for energy savings is
helping to drive the adoption of LED
lighting. LED light bulbs powered at
24V are widely used for home and
commercial applications. The use
of LV UltraMOV™ varistors at the
input circuit will enhance the surge
capability and protect the lifetime
of the LED light.
12V/24V/48V
DC Output
AC/DC
Industrial/Process Control Application
Industrial/Process Control Application
Inductive
Surge
Protection
(LV MOV
Applied
in parallel with the Relay Circuit as shown)
For industrial applications, relay
coils are commonly used for valve
switching for fluid/gas control.
L
+
28V
DC
CC
RC
C C = Stray Capacitance
L = Relay Coil Inductance
R C = Relay Coil Resistance
When the relay switches, the relay coil attempts to maintain current flow, causing temporary
high voltage spikes.
The use of an LV UltraMOV™ Varistor in parallel with the relay switch would extend the life of
the relay and reduce arcing during switching of the relay contacts. The UltraMOV™ varistor will
absorb the arcing energy from the energy released from the magnetic fields of the relay.
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DC Application Varistor Design Guide
How to Select a Low Voltage DC MOV
How to Select a Low Voltage DC MOV
Example of MOV selection process for surge protection:
Circuit conditions and requirements:
• 24VDC circuit
• Current waveform for surge is 8/20μs; voltage is 1.2/50μs
• Peak current during the surge is 1,000A
• Requirement is to survive 40 surges
• Other components (control IC, etc.) are rated to withstand 300V maximum.
Approach to finding a solution:
To find the voltage rating of the MOV, allow for 20% headroom to account for voltage swell
and power supply tolerances.
• 24V DC × 1.2 = 28.8V DC
• So look at 31V DC rated MOVs
• Determine which MOV disc size to use – identify those that minimally meet the 1,000A
surge requirement.
–– Use the Pulse Rating Curves in the LV UltraMOV™ Varistor Series datasheet to
determine pulse capabilities of each series per the 40 pulses @ 1,000A requirement
–– Use V-I Curve in the datasheet of the selected MOV to verify that the peak voltage will
be below the 1,000V ceiling.
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DC Application Varistor Design Guide
How to Select a Low Voltage DC MOV (continued)
• Determine the LV UltraMOV ™ Varistor disc size needed by confirming the surge rating
will meet the application requirement. In the following table, we have selected a 14mm
MOV with a 31V DC max continuous voltage rating as a possible solution to meet our
need. Then, we will use the Pulse Rating curves and V-I curves to verify that the selected
MOV can meet the requirements.
Part
Number
(Base
part)
Part
Number
(Base
part)
Size
(mm)
Vrms
(V) Vdc
(V)
Min
(V)
Nom
(V)
Max
(V)
Vc
(V)
I TM
(A)
V14E23P
V14P23P
14
23
28
32.4
36
39.6
71
4000
V05E25P
V05P25P
5
25
31
35.1
39
42.9
77
500
V07E25P
V07P25P
7
25
31
35.1
39
42.9
77
1000
V10E25P
V10P25P
10
25
31
35.1
39
42.9
77
2000
V14E25P
V14P25P
14
25
31
35.1
39
42.9
77
4000
V20E25P
V20P25P
20
25
31
35.1
39
42.9
77
8000
V10E30P
V10P30P
10
30
38
42.3
47
51.7
93
2000
V14E30P
V14P30P
14
30
38
42.3
47
51.7
93
4000
V20E30P
V20P30P
20
30
38
42.3
47
51.7
93
8000
Pulse Rating Curves:
Pulse Rating Curve for 20mm
Pulse Rating Curve for 14mm
V14x11P - V14x40P
V20x11P - V20x40P
10000
10000
1x
1x
1000
100
15x
102x
103x
104x
105x
106x
Surge Current (A)
Surge Current (A)
2x
10
1
1000
100
10
1
10
100
1000
10000
10
100
1000
10000
Impulse Duration (µs)
Impulse Duration (µs)
© 2015 Littelfuse • DC Application Varistor Design Guide
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15x
102x
103x
104x
105x
106x
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DC Application Varistor Design Guide
How to Select a Low Voltage DC MOV (continued)
Determine if the 14mm LV UltraMOV™ Varistor Surge Rating is sufficient
to meet the requirements:
1. Using the Repetitive Surge Capability (Pulse Rating) Curves in the LV UltraMOV ™ Varistor
datasheet, locate the pulse with (20µs) on the x-axis (see Fig 1 for 14mm MOV and Fig 2
for 20mm MOV). This signifies an 8/20μsec waveform shape.
2. Find where the vertical line intercepts the 1,000A point, which is our required surge
rating for 40 hits.
3. In this case, we find that the 14mm LV UltraMOV ™ Varistor can only survive a little more
than 10 hits. However, the 20mm choice can survive 100 pulses. Therefore, we select
the more conservative choice, which is the 20mm MOV (V20E25P).
1. Locate the peak current
on the X-axis (1000A)
in the LV UltraMOV ™
varistor V-I curve.
2. Find where it intercepts
Maximum Clamping Voltage for 20mm Parts
V20x11P - V20x40P
300
Maximum Peak Volts (V)
Determine if the 20mm
LV UltraMOV™ varistor
is suitable to meet the
clamping
requirements:
200
V20x25P
V20x20P
V20x17P
V20x14P
V20x11P
100
90
80
70
60
50
40
30
20
10 -3
the curve for the
MAXIMUM CLAMPING VOLTAGE
MODEL SIZE 20mm
10-2
10-1
10 0
101
10 2
103
10 4
Peak Amperes (A)
V20E25P product.
3. In this case, the
maximum clamping voltage is at 130V, which is beneath the 300V damage threshold for
the sensitive components in the circuit. Our LV UltraMOV ™ varistor selection will protect
us to the correct level.
Conclusion:
The V20E25P can meet the 24V DC, 1000A, 40-hit 8/20µs surge requirement with
clamping voltage at 130V.
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DC Application Varistor Design Guide
Transient Suppression Techniques
Transient Suppression Techniques
There are two different approaches to suppressing transients: attenuation and diversion.
Attenuation techniques are based on filtering the transient, thus preventing their
propagation into the sensitive circuit; diversion techniques redirect the transient away from
sensitive loads and thereby limit the residual voltages.
Clamping- and crowbar-type devices are often used to divert a transient:
• Crowbar devices, primarily gas tubes or protection thyristors, are widely used in the
communication field where power-follow current is less of a problem than in power
circuits. These types of devices employ a switching action to divert the transient and
reduce voltage below line condition by starving the circuit of power. These devices
require auto resetting.
• Clamping devices are components with a variable impedance that depends on the
voltage across the terminal. These devices exhibit a nonlinear impedance characteristic.
The variation of the impedance is continuous. A clamping device is designed to
maintain “normal” line conditions. It typically dissipates some energy within the body of
the device.
Overvoltage Suppression Comparison
The most suitable type of transient suppressor depends on the intended application; in
addition, some applications require the use of both primary and secondary protection
devices. The function of the transient suppressor is to limit the maximum instantaneous
voltage that can develop across the protected loads in one way or another. The choice
depends on various factors but ultimately comes down to a trade-off between the cost of
the suppressor and the level of protection needed.
When it’s used to protect sensitive circuits, the length of time a transient suppressor
requires to begin functioning is extremely important. If the suppressor is slow acting and a
fast-rising transient spike appears on the system, the voltage across the protected load can
rise to damaging levels before suppression kicks in. On power lines, a Metal Oxide Varistor
is usually the best type of suppression device. TVS Diodes and Gas Discharge Tubes are
also used occasionally.
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DC Application Varistor Design Guide
Transient Suppression Techniques (continued)
Typical Voltage
Clamping
Speeds
Typical
Capacitance/
Insertion Loss
Low thru
Medium
Moderate
High
Miniature Surface
Mount
Capable of withstanding
Metal-Oxide
very high energy transients;
Varistors (MOVs)
wide range of options
Medium thru
Very High
Moderate
High
Radial Leaded,
Industrial Terminal
Switches that turn to on
state and shunt overvoltage
to ground using a contained
inert gas as an insulator
Medium thru
High
Fast
Low
Surface Mount,
Axial Leaded,
2/3 Lead Radial
Extremely low capacitance;
Pulse-Guard® fast response time; compact
ESD Suppressors
size
Low
Moderate
Low
Miniature Surface
Mount
PLED LED
Protectors
Shunt function bypasses
open LEDs; ESD and reverse
power protection
Low
Very Fast
Medium
Miniature Surface
Mount
TVS Diode Array
SPA® Diodes
Low capacitance / low
clamping voltage; compact
size
Low thru
Medium
Very Fast
Low
Extensive range
of surface mount
options
TVS Diodes
Fast response to fast
transients; wide range of
options
Medium thru
High
Fast
High
Axial Leaded,
Radial Leaded,
Surface Mount
SIDACtor ®
Protection
Thyristors
Specifically designed to
serve stringent telecom/
networking standards
Medium thru
High
Very Fast
Low
Extensive range of
surface mount and
thru-hole options
Technology
Multi-Layer
Varistors (MLVs)
Gas Discharge
Tubes (GDTs)
Key Features and Protection Surge Energy
Characteristics
Rating Range
Compact and capable of
handling significant surges
for their size
Mounting Size/
Packaging Options
MOV General Applications
• Metal Oxide Varistors (MOVs) are commonly used to suppress transients in many
applications, such as Surge Protection Devices (SPD), Uninterruptible Power Supplies
(UPSs), AC Power Taps, AC Power Meters or other products.
• Lightning, inductive load switching, or capacitor bank switching are often the sources of
these overvoltage transients.
• Under normal operating conditions, the AC line voltage applied to an MOV is not expected
to exceed the MOV’s Maximum AC RMS Voltage Rating or Maximum Continuous
Operating Voltage (MCOV).
• Occasionally, overvoltage transients that exceed these limits may occur. These transients
are clamped to a suitable voltage level by the MOV, provided that the transient energy
does not exceed the MOV’s maximum rating.
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DC Application Varistor Design Guide
Introduction to Metal Oxide Varistors (MOVs)
Introduction to Metal Oxide Varistors (MOVs)
How to Connect a Littelfuse Varistor
Transient suppressors can be exposed to high currents for short durations (in the range of
nanoseconds to milliseconds).
Littelfuse varistors are connected in parallel to the load, and any voltage drop in the leads to
the varistor will reduce its effectiveness. Best results are obtained by using short leads to
reduce induced voltages.
DC Applications
DC applications require
connection between plus and
minus or plus and ground and
minus and ground.
COMMON
MODE
TRANSIENT
For example, if a transient
towards ground exists on all
three phases (common mode
transients), only transient
suppressors connected phase
to ground would absorb
Incorrect
Correct
energy. Transient suppressors
connected phase to phase
would not be effective.
© 2015 Littelfuse • DC Application Varistor Design Guide
18
www.littelfuse.com
DC Application Varistor Design Guide
Series and Parallel Operation of Varistors
Series and Parallel Operation of Varistors
In most cases, a designer can select a varistor that meets the desired voltage ratings from
the standard models listed in the catalog. Occasionally, however, the standard catalog
models do not fit the requirements of the application, either due to voltage ratings or
energy/current ratings. When this happens, two options are available: varistors can be
arranged in series or parallel to make up the desired ratings or a “special” can be requested
from the manufacturer to meet the unique requirements of the application.
Series Operation of Varistors
Varistors are applied in series for one of two reasons: to provide voltage ratings higher
than those available or to provide a voltage rating between the standard model voltages.
As a side benefit, higher energy ratings can be achieved with series connected varistors
over an equivalent single device. For instance, assume the application calls for a radial
leaded varistor with a VDC rating of 75VDC and an ITM peak current capability of 4000A.
The designer would like to have the varistor size fixed at 14mm. When we examine the LV
UltraMOV ™ Varistor series voltage ratings for 14mm size discs, part number V14E35P has
a maximum voltage of 45VDC. In order to support a 75VDC requirement, we will need to
place two MOVs in series. In this basic example, we would have the additive effects of
both varistors to get a total stand-off voltage of 45V + 45V = 90VDC. Therefore, we get
greater than 20% tolerance headroom over 75VDC, so this solution should be okay. The
clamping voltage (VC) is now the sum of the individual varistor clamping voltages or 220V at
10A. The peak current capability is still 4000A because the surge current will be conducted
through both varistors in series mode.
Parallel Operation of Varistors
Application requirements may necessitate higher peak currents and energy dissipation than
the high energy series of varistors can supply individually. When this occurs, the logical
alternative is to examine the possibility of configuring varistors in parallel. Fortunately, all
Littelfuse varistors have a property at high current levels that makes this feasible. This
property is the varistor’s series resistance, which is prominent during the “upturn region”
of the V-I characteristic. This upturn is due to the inherent linear resistance component of
the varistor characteristic. It acts as a series balancing (or ballasting) impedance to force a
degree of sharing that is not possible at lower current
For example, at a clamp voltage of 600V, the difference in current between a maximum
specified sample unit and a hypothetical 20% lower bound sample would be more than
20 to 1. Therefore, there is almost no current sharing and only a single varistor carries
the current. Of course, at low current levels in the range of 10A–100A, this may well be
acceptable.
© 2015 Littelfuse • DC Application Varistor Design Guide
19
www.littelfuse.com
DC Application Varistor Design Guide
Series and Parallel Operation of Varistors (continued)
Peak Voltage (V)
1000
LIMIT SAMPLE
800
600
500
400
300
200
LOWER BOUND (20%)
SAMPLE UNIT
TA = -40ºC TO 85ºC
100
0.1
0.5
1
MODEL V251BA60
5
10
50 100
500 1000
5000 10000
Peak Current (A)
Figure 22. Parallel operation of varistors by graphical
technique
With this technique, current sharing can be considerably improved from the near
worst-case conditions of the hypothetical example given in the preceding figure.
In summary, varistors can be paralleled, but good current sharing is only possible if the
devices are matched over the total range of the voltage-current characteristic.
In applications requiring paralleling, Littelfuse should be consulted. The following table
offers some guidelines for series and parallel operation of varistors.
Series
Objective
Higher voltage capability.
Higher energy capability.
Non-standard voltage capability.
Selection Required No
Parallel
Higher current capability.
Higher energy capability.
Yes
Model Applicable
All, must have same Itm rating.
All models
Application Range
All voltage and currents.
All voltages - only high currents,
i.e., >100A.
Precautions
Itm ratings must be equal.
Must be identical voltage rated models.
Must test and select units for similar V-I
characteristics.
Clamp voltages additive.
Voltage ratings additive.
Current ratings that of single
device.
Energy Wtm, ratings additive.
Current ratings function of current
sharing as determined graphically.
Energy ratings as above in proportion
to current sharing.
Clamp voltages determined by
composite V-I characteristic of
matched units.
Voltage ratings that of single unit.
Effect on Ratings
© 2015 Littelfuse • DC Application Varistor Design Guide
20
www.littelfuse.com
DC Application Varistor Design Guide
AUMOV® Varistor Series Specifications and Part Number Cross-References
AUMOV® Varistor Series Specifications and Part Number Cross-References
5mm Size
7mm Size
Vrms
Dimen- Voltage Min.
Max.
Min.
Max.
sion
Model mm (in.) mm (in.) mm (in.) mm (in.)
12
10
A
All
(0.472)
(0.394)
15
13
(0.59
A1
All
(0.512)
1)
9
7
ØD
All
(0.354)
(0.276)
4
4
6
6
e
All
(0.157) (0.157) (0.236) (0.236)
1
3
1
3
11 - 30
(0.039) (0.118) (0.039) (0.118)
e1
1.5
3.5
1.5
3.5
35 - 40
(0.059) (0.138) (0.059) (0.138)
5.0
5.0
11 - 30
(0.197)
(0.197)
E
5.6
5.6
35 - 40
(0.220)
(0.220)
0.585
0.685
0.585
0.685
Øb
All
(0.023) (0.027) (0.023) (0.027)
25.4
25.4
L
All
(1.00)
(1.00)
2.41
4.69
2.41
4.69
Ltrim
All
(0.095) (0.185) (0.095) (0.185)
© 2015 Littelfuse • DC Application Varistor Design Guide
21
10mm Size
14mm Size
20mm Size
Min.
Max.
Min.
Max.
Min.
Max.
mm (in.) mm (in.) mm (in.) mm (in.) mm (in.) mm (in.)
26.5
20
16
(1.043)
(0.787)
(0.630)
6.5
(0.256)
1
(0.039)
1.5
(0.059)
0.76
(0.030)
2.41
(0.095)
19.5
(0.768)
12.5
(0.492)
8.5
(0.335)
3
(0.118)
3.5
(0.138)
5.0
(0.197)
5.6
(0.220)
0.86
(0.034)
25.4
(1.00)
4.69
(0.185)
6.5
(0.256)
1
(0.039)
1.5
(0.059)
0.76
(0.030)
2.41
(0.095)
22.5
(0.886)
17
(0.669)
8.5
(0.335)
3
(0.118)
3.5
(0.138)
5.0
(0.197)
5.6
(0.220)
0.86
(0.034)
25.4
(1.00)
4.69
(0.185)
6.5
(0.256)
1
(0.039)
1.5
(0.059)
0.76
(0.030)
2.41
(0.095)
29
(1.142)
23
(0.906)
8.5
(0.335)
3
(0.118)
3.5
(0.138)
5.0
(0.197)
5.6
(0.220)
0.86
(0.034)
25.4
(1.00)
4.69
(0.185)
www.littelfuse.com
DC Application Varistor Design Guide
AUMOV® Varistor Series Specifications and Part Number Cross-References (continued)
AUMOV® Varistor Series Part Number Cross-Reference
Max.
Continuous
Voltage
Varistor
Voltage
at 1mA
Littelfuse Auto Series
Max.
Energy Jump
Peak Energy
(Load Start
Current Rating
Size
Dump,
DC
P/N
(8×20µs, (2ms,
Disc
∆Vv
10
Vjump
P/N
(Max. Op.
1 pulse 1 pulse)
Dia. Vrms Vdc
Vv (1mA) pulses (5 min.) (Max. Op.
Temp. 85°C) Temp. 125°C)
(A)
(J)
(mm) (V) (V) (1mA)
%
(J)
(V)
5
14
16
22
±10%
6
25
V05E14AUTO V05P14AUTO
400
1
For
12VDC
System
For
24VDC
System
For
48VDC
System
Supplier X
P/N
(SIOV-)
Supplier Z
Energy
Surge Rating
Rating (2ms,
8/20µs, 1 pulse)
1× (A)
(J)
P/N
(TVR-)
Energy
Surge Rating
Rating (2ms,
8/20µs, 1 pulse)
1× (A)
(J)
7
14
16
22
±10%
12
25
V07E14AUTO V07P14AUTO
800
2.2
S07K11AUTO
250
0.9
TVR07220-Q
500
10
14
16
22
±10%
25
25
V10E14AUTO V10P14AUTO
1500
5
S10K11AUTO
500
2
TVR10220-Q
1000
14
14
16
22
±10%
50
25
V14E14AUTO V14P14AUTO
3000
10
S14K11AUTO
1000
4
TVR14220-Q
2000
20
14
16
22
±10%
100
25
V20E14AUTO V20P14AUTO
5000
28
S17K11AUTO
2000
12
TVR20220-Q
3000
5
17
20
27
±10%
6
30
V05E17AUTO V05P17AUTO
400
1.4
7
17
20
27
±10%
12
30
V07E17AUTO V07P17AUTO
800
2.8
10
17
20
27
±10%
25
30
V10E17AUTO V10P17AUTO
1500
6.5
S10K17AUTO
500
2.5
TVR10270-Q
1000
14
17
20
27
±10%
50
30
V17E17AUTO V17P17AUTO
3000
13
S14K17AUTO
1000
5
TVR14270-Q
2000
20
17
20
27
±10%
100
30
V20E17AUTO V20P17AUTO
5000
35
S20K17AUTO
2000
14
TVR20270-Q
3000
5
25
28
39
±10%
6
40
V05E25AUTO V05P25AUTO
400
2.5
5.5
TVR14390-Q
2000
S20K25AUTO
2000
22
TVR20390-Q
3000
7
25
28
39
±10%
12
40
V07E25AUTO V07P25AUTO
800
10
25
28
39
±10%
25
40
V10E25AUTO V10P25AUTO
1500
13
14
25
28
39
±10%
50
40
V25E25AUTO V25P25AUTO
3000
25
20
25
28
39
±10%
100
40
V20E25AUTO V20P25AUTO
5000
77
3.1
5
30
34
47
±10%
6
45
V05E30AUTO V05P30AUTO
400
7
30
34
47
±10%
12
45
V07E30AUTO V07P30AUTO
800
7
10
30
34
47
±10%
25
45
V10E30AUTO V10P30AUTO
1500
15.5
14
30
34
47
±10%
50
45
V30E30AUTO V30P30AUTO
3000
32
S05K30AUTO
1000
9
TVR14470-Q
2000
20
30
34
47
±10%
100
45
V20E30AUTO V20P30AUTO
5000
90
S07K30AUTO
2000
26
TVR20170-Q
3000
5
42
50
68
±10%
6
50
V05E42AUTO V05P42AUTO
400
5
7
42
50
68
±10%
12
50
V07E42AUTO V07P42AUTO
800
11
S07K42AUTO
3
10
42
50
68
±10%
25
50
V10E42AUTO V10P42AUTO
1500
25
S10K42AUTO
6.4
TVR10680-Q
1000
14
42
50
68
±10%
50
50
V42E42AUTO V42P42AUTO
3000
50
S14K42AUTO
13
TVR14680-Q
2000
20
42
50
68
±10%
100
50
V20E42AUTO V20P42AUTO
5000
140
S20K42AUTO
37
TVR20680-Q
3000
© 2015 Littelfuse • DC Application Varistor Design Guide
22
www.littelfuse.com
DC Application Varistor Design Guide
LV UltraMOV™ Varistor Series Specifications and Part Number Cross-References
LV UltraMOV™ Varistor Series Specifications and Part Number
Cross-References
The following excerpt is from the LV UltraMOV ™ Varistor Series datasheet. There is also
a comparison of specifications for the LV UltraMOV ™ Varistor Series vs. the Littelfuse ZA
Series and another well-known MOV supplier.
Max.
Continuous
Voltage
Model Number
Part Number
(Base part) Branding
Size Vrms
(mm) (V)
Max.
Clamping
Voltage
Vdc
(V)
Min
(V)
Nom
(V)
Max
(V)
Vc
(V)
Ipk
(A)
Max. Peak
Current
(8×20µs,
1 pulse)
(A)
Varistor Voltage
at 1mA
Energy
Typical
Rating
Capacitance
(2ms, 1pulse)
f=1MHz
(J)
(pF)
V05E17
5E17
5
17
22
24.3
27.0
29.7
53
1
500
1.4
950
V07E17
7E17
7
17
22
24.3
27.0
29.7
53
2.5
1000
2.8
2100
V10E40
10E40
10
40
56
61.2
68.0
74.8
135
5
2000
25
1850
V14E40
14E40
14
40
56
61.2
68.0
74.8
135
10
4000
50
4000
V20E40
20E40
20
40
56
61.2
68.0
74.8
135
20
8000
140
8500
Supplier X
Standard Series
Littelfuse
ZA Series
Littelfuse
LV UltraMOV ™ Varistor
Series
Diameter
(mm)
Vrms
(V)
Vdc
(V)
Imax
(8/20)(A)
Wmax
(2ms)(J)
Imax
(8/20)(A)
Imax
(8/20)(A)
Wmax
(2ms)(J)
5
11~40
14~56
100
0.3~1.3
100
500
0.8~5
7
11~40
14~56
250
0.8~3.0
250
1000
2~11
10
11~40
14~56
500
1.7~6.4
500
2000
42~25
14
11~40
14~56
1000
3.2~13
1000
4000
8~50
20
11~40
14~56
2000
10~37
2000
8000
25~140
Supplier X
Standard Series
Littelfuse
ZA Series
Littelfuse
LV UltraMOV ™ Varistor
Series
Diameter
(mm)
Vrms
(V)
Vdc
(V)
Imax
(8/20)(A)
Wmax
(2ms)(J)
Imax
(8/20)(A)
Imax
(8/20)(A)
Wmax
(2ms)(J)
5
50~95
65~125
400
1.8~3.4
400
800
5~9
7
50~95
65~125
1200
4.2~7.6
1200
1750
10~18
10
50~95
65~125
2500
8.4~15
2500
3500
20~36
14
50~95
65~125
4500
15~25
4500
6500
40~75
20
50~95
65~125
6500
27~50
6500
10000
80~150
© 2015 Littelfuse • DC Application Varistor Design Guide
23
www.littelfuse.com
DC Application Varistor Design Guide
LV UltraMOV™ Varistor Series Specifications and Part Number Cross-References (continued)
LV UltraMOV™ Varistor Series Part Number Cross-Reference
Supplier X
Standard Series
Diameter Vrms
(mm)
(V)
5
11
7
11
10
11
14
11
20
11
5
14
7
14
10
14
14
14
20
14
5
17
7
17
10
17
14
17
20
17
5
20
7
20
10
20
14
20
20
20
5
23
7
23
10
23
14
23
20
23
5
25
7
25
10
25
14
25
20
25
5
30
7
30
10
30
14
30
20
30
5
35
7
35
10
35
14
35
20
35
5
40
7
40
10
40
14
40
20
40
Vdc
(V)
14
14
14
14
14
18
18
18
18
18
22
22
22
22
22
26
26
26
26
26
28
28
28
28
28
31
31
31
31
31
38
38
38
38
38
45
45
45
45
45
56
56
56
56
56
P/N
(SIOV-)
S05K11
S07K11
S10K11
S14K11
S20K11
S05K14
S07K14
S10K14
S14K14
S20K14
S05K17
S07K17
S10K17
S14K17
S20K17
S05K20
S07K20
S10K20
S14K20
S20K20
S05K25
S07K25
S10K25
S14K25
S20K25
S05K30
S07K30
S10K30
S14K30
S20K30
S05K35
S07K35
S10K35
S14K35
S20K35
S05K40
S07K40
S10K40
S14K40
S20K40
Imax
(8/20)
(A)
100
250
500
1000
2000
100
250
500
1000
2000
100
250
500
1000
2000
100
250
500
1000
2000
100
250
500
1000
2000
100
250
500
1000
2000
100
250
500
1000
2000
100
250
500
1000
2000
Wmax
(2ms)(J)
0.3
0.8
1.7
3.2
10
0.4
0.9
2
4
12
0.5
1.1
2.5
5
14
0.6
1.3
3.1
6
18
0.7
1.6
3.7
7
22
0.9
2
4.4
9
26
1.1
2.5
5.4
10
33
1.3
3
6.4
13
37
© 2015 Littelfuse • DC Application Varistor Design Guide
Supplier Y
Standard Series
P/N
(ERZV-)
ERZV05D180
ERZV07D180
ERZV10D180
ERZV14D180
ERZV20D180
ERZV05D220
ERZV07D220
ERZV10D220
ERZV14D220
ERZV20D220
ERZV05D270
ERZV07D270
ERZV10D270
ERZV14D270
ERZV20D270
ERZV05D330
ERZV07D330
ERZV10D330
ERZV14D330
ERZV20D330
ERZV05D390
ERZV07D390
ERZV10D390
ERZV14D390
ERZV20D390
ERZV05D470
ERZV07D470
ERZV10D470
ERZV14D470
ERZV20D470
ERZV05D560
ERZV07D560
ERZV10D560
ERZV14D560
ERZV20D560
ERZV05D680
ERZV07D680
ERZV10D680
ERZV14D680
ERZV20D680
Imax
(8/20)
(A)
250
500
1000
2000
3000
250
500
1000
2000
3000
250
500
1000
2000
3000
250
500
1000
2000
3000
250
500
1000
2000
3000
250
500
1000
2000
3000
250
500
1000
2000
3000
250
500
1000
2000
3000
24
Littelfuse
LV UltraMOV ™ Varistor Series
P/N
Wmax
(Max. Op.
(2ms)(J) Temp. 85°C)
0.4
V05E11P
0.9
V07E11P
2.2
V10E11P
4.3
V14E11P
12
V20E11P
0.5
V05E14P
1.1
V07E14P
2.6
V10E14P
5.3
V14E14P
14
V20E14P
0.7
V05E17P
1.3
V07E17P
3.2
V10E17P
6.5
V14E17P
17
V20E17P
0.8
V05E20P
1.6
V07E20P
4
V10E20P
7.9
V14E20P
21
V20E20P
V05E23P
V07E23P
V10E23P
V14E23P
V20E23P
0.9
V05E25P
1.9
V07E25P
4.7
V10E25P
9.4
V14E25P
25
V20E25P
1.1
V05E30P
2.3
V07E30P
5.6
V10E30P
11
V14E30P
30
V20E30P
1.3
V05E35P
2.7
V07E35P
6.7
V10E35P
13
V14E35P
36
V20E35P
1.6
V05E40P
3.3
V07E40P
8.2
V10E40P
16
V14E40P
44
V20E40P
P/N
(Max. Op.
Temp. 125°C)
V05P11P
V07P11P
V10P11P
V14P11P
V20P11P
V05P14P
V07P14P
V10P14P
V14P14P
V20P14P
V05P17P
V07P17P
V10P17P
V14P17P
V20P17P
V05P20P
V07P20P
V10P20P
V14P20P
V20P20P
V05P23P
V07P23P
V10P23P
V14P23P
V20P23P
V05P25P
V07P25P
V10P25P
V14P25P
V20P25P
V05P30P
V07P30P
V10P30P
V14P30P
V20P30P
V05P35P
V07P35P
V10P35P
V14P35P
V20P35P
V05P40P
V07P40P
V10P40P
V14P40P
V20P40P
Imax
(8/20)
(A)
500
1000
2000
4000
8000
500
1000
2000
4000
8000
500
1000
2000
4000
8000
500
1000
2000
4000
8000
500
1000
2000
4000
8000
500
1000
2000
4000
8000
500
1000
2000
4000
8000
500
1000
2000
4000
8000
500
1000
2000
4000
8000
Wmax
(2ms)(J)
0.8
2.0
4.2
8
25
1
2.2
5
10
28
1.4
2.8
6.5
13
35
2
4.2
10
20
58
2.2
5
12
23
70
2.5
5.5
13
25
77
3.1
7
15.5
32
90
4
9
20
40
115
5
11
25
50
140
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DC Application Varistor Design Guide
LV UltraMOV™ Varistor Series Specifications and Part Number Cross-References (continued)
LV UltraMOV™ Varistor Series Part Number Cross-Reference (continued)
Supplier X
Standard Series
Diameter Vrms
(mm)
(V)
5
50
7
50
10
50
14
50
20
50
5
60
7
60
10
60
14
60
20
60
5
75
7
75
10
75
14
75
20
75
5
95
7
95
10
95
14
95
20
95
Vdc
(V)
65
65
65
65
65
85
85
85
85
85
100
100
100
100
100
125
125
125
125
125
P/N
(SIOV-)
S05K50
S07K50
S10K50
S14K50
S20K50
S05K60
S07K60
S10K60
S14K60
S20K60
S05K75
S07K75
S10K75
S14K75
S20K75
S05K95
S07K95
S10K95
S14K95
S20K95
Imax
(8/20)
(A)
400
1200
2500
4500
6500
400
1200
2500
4500
6500
400
1200
2500
4500
6500
400
1200
2500
4500
6500
© 2015 Littelfuse • DC Application Varistor Design Guide
Wmax
(2ms)(J)
1.8
4.2
8.4
15.0
27
2.2
4.8
10
17
33
2.5
5.9
12
20
40
3.4
7.6
15
25
50
Supplier Y
Standard Series
P/N
(ERZV-)
ERZV05D820
ERZV07D820
ERZV10D820
ERZV14D820
ERZV20D820
ERZV05D101
ERZV07D101
ERZV10D101
ERZV14D101
ERZV20D101
ERZV05D121
ERZV07D121
ERZV10D121
ERZV14D121
ERZV20D121
ERZV05D151
ERZV07D151
ERZV10D151
ERZV14D151
ERZV20D151
25
Imax
(8/20)
(A)
800
1750
3500
6000
10000
800
1750
3500
6000
10000
800
1750
3500
6000
10000
800
1750
3500
6000
10000
Littelfuse
LV UltraMOV ™ Varistor Series
P/N
Wmax
(Max. Op.
(2ms)(J) Temp. 85°C)
2.5
V05E50P
5
V07E50P
10
V10E50P
20
V14E50P
40
V20E50P
3
V05E60P
6
V07E60P
12
V10E60P
25
V14E60P
50
V20E60P
3.5
V05E75P
7
V07E75P
14.5
V10E75P
30
V14E75P
60
V20E75P
4.5
V05E95P
9
V07E95P
18
V10E95P
37.5
V14E95P
75
V20E95P
P/N
(Max. Op.
Temp. 125°C)
V05P50P
V07P50P
V10P50P
V14P50P
V20P50P
V05P60P
V07P60P
V10P60P
V14P60P
V20P60P
V05P75P
V07P75P
V10P75P
V14P75P
V20P75P
V05P95P
V07P95P
V10P95P
V14P95P
V20P95P
Imax
(8/20)
(A)
800
1750
3500
6500
10000
800
1750
3500
6500
10000
800
1750
3500
6500
10000
800
1750
3500
6500
10000
Wmax
(2ms)(J)
5
10
20
40
80
6
12
24
50
100
7
14
29
60
120
9
18
36
75
150
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DC Application Varistor Design Guide
LV UltraMOV™ Varistor Series Specifications and Part Number Cross-References (continued)
LV UltraMOV™ Varistor Series Cross-Reference (by ITM)
Supplier X
Standard Series
Imax
(8/20)
(A)
100
250
500
1000
6500
Vrms
(V)
Vdc
(V)
11
Diam.
(mm)
Supplier Y
Standard Series
P/N
(SIOV-)
Wmax
(2ms) (J)
14
S05K11
0.3
14
18
S05K14
0.4
17
22
S05K17
0.5
20
26
S05K20
0.6
25
31
30
5
S05K25
0.7
38
S05K30
0.9
35
45
S05K35
1.1
40
56
S05K40
1.3
Diam.
(mm)
P/N
(ERZV-)
Littelfuse
LV UltraMOV ™ Varistor Series
Wmax Diam.
(2ms)(J) (mm)
11
14
S07K11
0.8
ERZV05D180
0.4
14
18
S07K14
0.9
ERZV05D220
0.5
17
22
S07K17
1.1
ERZV05D270
0.7
ERZV05D330
0.8
ERZV05D390
0.9
ERZV05D470
1.1
S07K20
1.3
S07K25
1.6
38
S07K30
2
20
26
25
31
30
7
5
35
45
S07K35
2.5
ERZV05D560
1.3
40
56
S07K40
3
ERZV05D680
1.6
P/N
(Max. Op.
Temp. 85°C)
P/N
(Max. Op.
Wmax
Temp. 125°C) (2ms) (J)
11
14
S10K11
1.7
ERZV07D180
0.9
V05E11P
V05P11P
14
18
S10K14
2
ERZV07D220
1.1
V05E14P
V05P14P
1
17
22
S10K17
2.5
ERZV07D270
1.3
V05E17P
V05P17P
1.4
S10K20
3.1
ERZV07D330
1.6
20
26
23
28
25
31
S10K25
3.7
30
38
S10K30
35
45
S10K35
40
56
11
14
14
18
10
-
7
-
5
0.8
V05E20P
V05P20P
2
V05E23P
V05P23P
2.2
ERZV07D390
1.9
V05E25P
V05P25P
2.5
4.4
ERZV07D470
2.3
V05E30P
V05P30P
3.1
5.4
ERZV07D560
2.7
V05E35P
V05P35P
4
S10K40
6.4
ERZV07D680
3.3
V05E40P
V05P40P
5
S14K11
3.2
ERZV10D180
2.2
V07E11P
V07P11P
2
S14K14
4
ERZV10D220
2.6
V07E14P
V07P14P
2.2
17
22
S14K17
5
ERZV10D270
3.2
V07E17P
V07P17P
2.8
20
26
S14K20
6
ERZV10D330
4
V07E20P
V07P20P
4.2
23
28
-
V07E23P
V07P23P
5
14
10
-
7
25
31
S14K25
7
ERZV10D390
4.7
V07E25P
V07P25P
5.5
30
38
S14K30
9
ERZV10D470
5.6
V07E30P
V07P30P
7
35
45
S14K35
10
ERZV10D560
6.7
V07E35P
V07P35P
9
40
56
S14K40
13
ERZV10D680
8.2
V07E40P
V07P40P
11
50
65
S20K50
27
V14E50P
V14P50P
40
60
85
S20K60
33
V14E60P
V14P60P
50
75
100
S20K75
40
V14E75P
V14P75P
60
95
125
S20K95
50
V14E95P
V14P95P
75
20
© 2015 Littelfuse • DC Application Varistor Design Guide
14
26
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DC Application Varistor Design Guide
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