PRODUCT
CATALOG
& DESIGN
GUIDE
Metal-Oxide Varistor (MOV)
Metal-Oxide Varistors
(MOVs)
TABLE OF CONTENTS
Introduction to Overvoltage Suppression
Varistor Characteristics, Terms and Consideration Factors
Varistor Connection Examples
Varistor Selection Worksheet
Agency Standards
Legal Disclaimers
Mount/Form
Factor
Disc Size
UL
CSA
VDE
CECC
QPL
RoHS
Lead Free
Halogen Free
Agency Approvals
•
•
1
-55 to +125°C
Surface Mount
4
•
-55 to +85°C
1
•
•
5, 7, 10, 14, 20mm
7, 10, 14, 20mm
-55 to +85°C
1
Radial Leaded
25mm
10, 14, 20mm
7, 10, 14, 20mm
• • • •
• •
• • • •
• • • •
• •
Not Applicable
•
•
•
•
•
•
• •
• • •
• • •
• • •
• •
• • •
• • •
• • •
•
•
•
• •
• •
• •
• • •
•
•
• • •
• • •
• • •
• • •
• •
•
• •
•
•
•
• •
• •
• •
• •
• •
• •
• •
• •
•
Series Name
1
Image
Operating
Operating Operating
Technology
Lines
Peak Current Peak Energy
Temperature
AC Voltage DC Voltage
2
Range (J)
Type
Protected
Range (A)
Range
Range
Range
Surface Mount MLVs and MOVs:
MHS
MLE
0201 MLA
MLA
MLA Automotive
AUML
MLN
CH
SM7
SM20
Zinc
Oxide
(MOV)
4 - 14
14 - 275
50 - 510
20 - 320
11 - 95
130 - 625
115 - 750
Zinc
Oxide
130 - 1000
130 - 1000
4 - 460
14 - 42
11 - 625
130 - 2800
130 - 750
Zinc
Oxide
110 - 750
110 - 750
110 - 750
250 - 2800
9 - 264
Zinc
Oxide
4 - 275
130 - 320
175 - 1200
5.5 - 615
16 - 50
14 - 825
Multi-
Layer
Zinc
Oxide
(MLV)
9 - 42
18
5.5
2.5 - 107
2.5 - 40
3.5 - 120
3.5 - 48
18 - 48
5.5 - 18
18 - 369
68 - 675
26 - 420
14 - 127
170 - 825
150 - 970
30
100 - 400
1200
6500
500 - 10000
1750 -10000
22000
3500 - 10000
1200 - 6500
50 - 6500
400 - 5000
4 - 500
500
0.02 - 2.5
0.1 - 2.5
1.5 - 25
0.05 - 0.10
1.0 - 8.0
10 - 40
165
0.8 - 150
12.5 - 400
230 - 890
40 - 530
11 - 360
0.1 - 52
1.0 to 140
4.2 - 490
-40 to +125°C
Radial Leaded MOVs:
LV UltraMOV
®
Varistor
UltraMOV
®
Varistor
UltraMOV 25S Varistor
®
C-III
LA
ZA
AUMOV Varistor
®
5, 7, 10, 14, 20mm •
5, 7, 10, 14, 20mm •
10, 14, 20mm
60mm
40mm
32, 40mm
34mm
34mm
60mm
Not Applicable
Not Applicable
7, 10, 14, 20mm
HMOV
BA/BB
DA/DB
HA
HB34, HF34, HG34
DHB34
CA
Industrial High Energy Terminal MOVs:
175 - 3500 50000 - 70000 450 - 10000
175 - 970
148 - 970
148 - 970
40000
40000
40000
270 - 1050
220 - 1050
220 - 1050
-55 to +85°C
1
148 - 970 25000 - 40000 160 - 1050
Screw /
Clip Terminals
Industrial
Packaged Radial
Leads
Bare Disc
-55 to +85°C
-55 to +125°C
-55 to +85°C
1
Axial Leaded
Inline Radial
Leads
(Varies)
330 - 3500 20000 - 70000 880 - 10000
13 - 365
5.5 - 369
175 - 420
40 - 100
100 - 6500
6000
0.06 - 1.7
0.4 - 160
50 - 120
Specialty Application MOVs:
MA
RA
High Reliability
Thermally Protected MOVs:
TMOV
®
Varistor/
iTMOV
®
Varistor
TMOV
®
25S Varistor
TMOV
®
34S Varistor
SMOV
®
25S Varistor
SMOV
®
34S Varistor
FBMOV
Zinc
Oxide
115 - 750
115 - 750
115 - 750
115 - 750
115 - 750
115 - 750
150 - 970
150 - 970
150 - 970
150 - 970
150 - 970
150 - 970
6000 - 10000
20000
40000
20000
40000
40000
35 - 480
Radial Leaded
170 - 670
280 - 1200
170 - 670
280 - 1200
340 - 1340
-45 to +75°C
-55 to +85°C
-55 to +85°C
1
Industrial
Packaged Radial
Leads
Bolt
Terminal
25mm
34mm
25mm
34mm
14, 20mm
© 2017 Littelfuse, Inc.
© 2017 Littelfuse, Inc.
Specifications are subject toand illustrative material in this literature are
Specifications, descriptions change without notice.
as accurate as known at the time of publication, but are subject to change
Revised: 09/14/17
without notice. Visit
www.littelfuse.com
for more information.
(1) Detailed information about most product series listed here can be found on our web.
(2) Not an applicable parameter for Crowbar devices
(3) AUMOV
®
Varistor: Energy rating (auto lad dump) for impulse duration of 40ms minimum to one half of of peak current, 60 second interval (ISO7637-2 5a).
Metal-Oxide Varistors
(MOVs)
Introduction to Overvoltage Suppression
To assure reliable operation, transient voltage suppression
should be considered at early stages of the design process.
This can be a complex task as electronic components are
increasingly sensitive to stray electrical transients. The
designer must define the types of transient threats and
determine what applications are needed while meeting the
product agency norms and standards.
Varistors are increasingly used as the front-line solution for
transient surge protection. Littelfuse provides expertise
to the designer and offers the broadest range of circuit
protection technologies to choose from.
Littelfuse varistors are available in a variety of forms to
serve a wide range of applications. Options include ultra
small surface mount multi-layer suppressor (MLV) devices
for small electronics applications, and traditional mid-
range metal-oxide (MOV) radial and axial leaded devices
for protection of small machinery, power sources and
components. Littelfuse also offers larger terminal mount
MOVs for industrial applications.
A more recent innovation to the the Littelfuse product
line, MLVs address a specific part of the transient
voltage spectrum – the circuit board level environment
where, although lower in energy, transients from ESD,
inductive load switching, and even lightning surge
remnants would otherwise reach sensitive integrated
circuits. Each of these events can relate to a product’s
ElectroMagnetic Compatibility (EMC), or its immunity to
transients that could cause damage or malfunction.
Littelfuse offers five distinct versions of MLVs including
the MHS Series ESD Suppressor for high data rates, the
ML Series which supports the broadest application range,
the MLE Series intended for ESD while providing filter
functions, the MLN Series Quad Array in a 1206 & 0805
chip and the AUML Series characterized for the specific
transients found in automotive electronic systems.
This catalog and design guide includes selection tables,
technology tutorials, and detailed product technical
information, to aid you in choosing the correct Littelfuse
Varistor to serve your application.
Please visit
www.littelfuse.com
regularly to find the most
current Littelfuse varistor product information.
Additional design support information can be found at
www.littelfuse.com/design-support.html
Varistor Application Guides
MARKET
SEGMENT
Low Voltage, Board Level Products
•
•
•
•
TYPICAL APPLICATIONS AND CIRCUIT EXAMPLES
Hand-Held/Portable Devices
EDP
Computer
I/O Port and Interfaces
•
•
•
•
Controllers
Instrumentation
Remote Sensors
Medical Electronics, Etc.
DEVICE FAMILY OR SERIES
CH
MA, ZA, RA
ML, MLE, MLN, MHS
AC Line, TVSS Products
•
•
•
•
•
•
•
•
•
•
UPS
AC Panels
AC Power Taps
TVSS Devices
AC Appliance/Controls
ABS
EEC
Instrument Center
Air Bag
Window Control/ Wiper
Modules
•
•
•
•
Power Meters
Power Supplies
Circuit Breakers
Consumer Electronics
TMOV
®
, UltraMOV™, C-111,
LA, HA, HB, HG, HF DHB,
,
TMOV34S
®
, RA
CH
•
•
•
Body Controllers
Multiplex Bus
EFI
CH
ZA
AUML, ML, MLE, MLN, MHS
•
•
•
•
Repeaters
Line Cards
COE
T1/E1/ISDN
CH
ZA
ML, MLE, MLN, MHS
•
•
Robotics
Large Motors/Pumps/
Compressors
TECHNOLOGY
MOV
MOV
MLV
SURFACE MOUNT
PRODUCTs
√
√
MOV
MOV
MOV
MOV
MLV
MOV
MOV
MLV
√
√
Automotive Electronics
√
√
Telecommunictions Products
• Cellular/Cordless Phone
• Modems
• Secondary Phone Line
Protectors
• Data Line Connectors
•
•
•
•
High Current Relays
Solenoids
Motor Drives
AC Distrbution Panels
√
Industrial High Energy AC Products
DA/DB, BA/BB, CA, HA, HB,
HC, HG, HF DHB, TMOV34S
®
,
MOV
Available in both surfacemount and through-hole packages.
© 2017 Littelfuse, Inc.
Specifications are subject to change without notice.
Revised: 09/14/17
Metal-Oxide Varistors
(MOVs)
Introduction to Overvoltage Suppression (continued)
Transient Threats – What Are Transients?
Voltage transients are defined as short duration surges of
electrical energy and are the result of the sudden release
of energy that was previously stored, or induced by other
means, such as heavy inductive loads or lightning strikes.
In electrical or electronic circuits, this energy can be
released in a predictable manner via controlled switching
actions, or randomly induced into a circuit from external
sources.
Repeatable transients are frequently caused by the
operation of motors, generators, or the switching of
reactive circuit components. Random transients, on the
other hand, are often caused by Lightning (Figure 1) and
Electrostatic Discharge (ESD) (Figure 2). Lightning and ESD
generally occur unpredictably, and may require elaborate
monitoring to be accurately measured, especially if induced
at the circuit board level. Numerous electronics standards
groups have analyzed transient voltage occurrences
using accepted monitoring or testing methods. The key
characteristics of several transients are shown below in
Table 1.
Vp
Vp/2
100
90
%
Current (I) %
I30
I60
30n
60n
t
r
= 0.7 to 1.0ns
Figure 2. ESD Test Waveform
Why are Transients of Increasing Concern?
Component miniaturization has resulted in increased
sensitivity to electrical stresses. Microprocessors for
example, have structures and conductive paths which
are unable to handle high currents from ESD transients.
Such components operate at very low voltages, so
voltage disturbances must be controlled to prevent device
interruption and latent or catastrophic failures. Sensitive
devices such as microprocessors are being adopted at
an exponential rate. Microprocessors are beginning to
perform transparent operations never before imagined.
Everything from home appliances, such as dishwashers, to
industrial controls and even toys, have increased the use of
microprocessors to improve functionality and efficiency.
Vehicles now employ many electronics systems to
control the engine, climate, braking and, in some cases,
steering systems. Some of the innovations are designed
to improve efficiency, but many are safety related, such as
ABS and traction control systems. Many of the features in
appliances and automobiles use modules which present
transient threats (such as electric motors). Not only is
the general environment hostile, but the equipment or
appliance can also be sources of threats. For this reason,
careful circuit design and the correct use of overvoltage
protection technology will greatly improve the reliability
and safety of the end application. Table 2 shows the
vulnerability of various component technologies.
Device Type
Vulnerability (volts)
30-1800
100-200
100-300
100
140-7000
250-3000
300-2500
380-7000
680-1000
t1
t2
t
Figure 1. Lightning Transient Waveform
VOLTAGE
Lighting
Switching
EMP
ESD
25kV
600V
1kV
15kV
CURRENT
20kA
500A
10A
30A
RISE-TIME DURATION
10µs
50µs
20ns
<1ns
1ms
500ms
1ms
100ns
Table 1. Examples of transient sources and magnitude
Characteristics of Transient Voltage Spikes
Transient voltage spikes generally exhibit a "double
exponential" wave form, shown in Figure 1 for lightning and
figure 2 for ESD. The exponential rise time of lightning is in
the range 1.2µs to 10µs (essentially 10% to 90%) and the
duration is in the range of 50µs to 1000µs (50% of peak
values). ESD on the other hand, is a much shorter duration
event. The rise time has been characterized at less than 1
ns. The overall duration is approximately 100ns.
VMOS
MOSFET
GaAsFET
EPROM
JFET
CMOS
Schottky Diodes
Bipolar Transistors
SCR
Table 2: Range of device vulnerability.
© 2017 Littelfuse, Inc.
Specifications are subject to change without notice.
Revised: 09/14/17
Metal-Oxide Varistors
(MOVs)
Introduction to Overvoltage Suppression (continued)
Transient Voltage Scenarios
ESD (Electrostatic Discharge)
Electrostatic discharge is characterized by very fast rise
times and very high peak voltages and currents. This
energy is the result of an imbalance of positive and
negative charges between objects.
Below are some examples of the voltages which can be
generated, depending on the relative humidity (RH):
•
•
•
•
•
Walking across a carpet:
35kV @ RH = 20%; 1.5kV @ RH = 65%
Walking across a vinyl floor:
12kV @ RH = 20%; 250V @ RH = 65%
Worker at a bench:
6kV @ RH = 20%; 100V @ RH = 65%
Vinyl envelopes:
7kV @ RH = 20%; 600V @ RH = 65%
Poly bag picked up from desk:
20kV @ RH = 20%; 1.2kV @ RH = 65%
90%
V
S
10%
V
T
T
1
V
B
V
B
= 25V to 125V
T
1
= 5ms to 10ms
V
B
= 14V
R = 0.5 to 4
T = 40ms to 400ms
t
Figure 3. Automotive Load Dump
Referring to Table 2 on the previous page, it can be
seen that ESD that is generated by everyday activities
can far surpass the vulnerability threshold of standard
semiconductor technologies. Figure 2 shows the
ESD waveform as defined in the IEC 61000-4-2 test
specification.
Inductive Load Switching
The switching of inductive loads generates high energy
transients which increase in magnitude with increasingly
heavy loads. When the inductive load is switched off, the
collapsing magnetic field is converted into electrical energy
which takes the form of a double exponential transient.
Depending on the source, these transients can be as large
as hundreds of volts and hundreds of Amps, with duration
times of 400ms.
Typical sources of inductive transients are:
•
•
•
•
Generator
Motor
Relay
Transformer
Figure 3, shows a transient which is the result of stored
energy within the alternator of an automobile charging
system. A similar transient can also be caused by other
DC motors in a vehicle. For example, DC motors power
amenities such as power locks, seats and windows.
These various applications of a DC motor can produce
transients that are just as harmful to the sensitive
electronic components as transients created in the external
environment.
Lightning Induced Transients
Even though a direct strike is clearly destructive, transients
induced by lightning are not the result of a direct strike.
When a lightning strike occurs, the event creates a
magnetic field which can induce transients of large
magnitude in nearby electrical cables.
Figure 4, shows how a cloud-to-cloud strike will effect
not only ove RHead cables, but also buried cables. Even a
strike 1 mile distant (1.6km) can generate 70V in electrical
cables.
Buried Line
Transient Generated:
• 70 V at 1.6km (1 mile)
• 10 kV at 150m (160 yards)
These examples are extremely common in electrical and
electronic systems. Because the sizes of the loads vary
according to the application, the wave shape, duration,
peak current and peak voltage are all variables which
exist in real world transients. Once these variables can be
approximated, a suitable suppressor technology can be
selected.
Figure 4. Cloud-to-Cloud Lightning Strike
© 2017 Littelfuse, Inc.
Specifications are subject to change without notice.
Revised: 09/14/17
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