Littelfuse SMOV34S User Manual

Varistor Products

Thermally Protected Varistors > SMOV34S Series

SMOV34S Varistor Series

Agency Approvals

Agency Agency File Number

E320116

RoHS

Description

The Littelfuse SMOV thermally protected varistor is a self­protected device. It consists of a 34mm square varistor with
an integral thermal disconnect designed to open in the event of
overheating due to abnormal overvoltage as outlined in UL1449
3rd edition. The SMOV helps facilitate SPD module compliance
to UL1449 and offers quick thermal response due to the close
proximity of the integrated thermal element to the MOV body.
This configuration also offers lower inductance than most discreet
solutions resulting in improved clamping performance to fast over
voltage transients.

The device has a separate micro-switch, which can be used to
indicate that the MOV has been disconnected from the circuit. This
separate switch makes the monitoring circuitry completely isolated
from the main power which ensures indicator circuit safety and
simplifies the customers circuit design.

Features

• Maximum single
surge capability 40 kA,
8/20 waveshape.

• Nominal Discharge
Current Value: 20kA.

• Intermediate current
rating: 50A/150A.

• -45°C to +75°C operating
temperature.

• Recognized to UL
1449 3rd edition.

• Lead-Free and RoHS
compliant.

• Integrated micro-switch
for indication
circuitry/design.

Applications

• SPD applications

• AC/DC distribution

• T/Data center

• Power supplier

• Telecommunication

Absolute Maximum Ratings

• For ratings of individual members of a series, see Device Ratings and Specifications chart

SMOV34S Series
Continous:

Steady State Applied Voltage:

DC Voltage Range (VM(DC)) 150 to 970 V

AC Voltage Range (V

Transient:

Non-Repetitive Surge Current, 8/20µs Waveform (ITM) 40,000 A

Non-Repetitive Energy Capability, 2ms Waveform (WTM) 280 to 1200 J

Operating Ambient Temperature Range (TA) -45 to +75 °C

Storage Temperature Range (T

Hi-Pot Encapsulation (Isolation Voltage Capability) 2500 V

Isolation Voltage Capability (when the thermal disconnect opens) 1500 V

Housing Insulation Resistance >1,000 MΩ

CAUTION: Stresses above those listed in “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress only rating and operation
of the device at these or any other conditions above those indicated in the operational sections of this specification is not implied.

) -45 to +85 °C

STG

) 115 to 750 V

M(AC)RMS

Units

SMOV34S Series

© 2013 Littelfuse, Inc.
Specifications are subject to change without notice.
Please refer to www.littelfuse.com/series/smov34s.html for current information.

243

Revised: May 8, 2013

HI–ENERGY MOV’S

SMOV34S Varistor Series

Varistor Products

Thermally Protected Varistors > SMOV34S Series

SMOV34S Series Ratings & Specifications

Maximum Rating (75°C) Specifications (25 °C)

Part

Number

Continuous Transient

Peak

AC

Volts

DC

Volts

Energy

2ms

Surge

Current

8/20μs

V

M (AC)

RMS

V

M(DC)

W

TM

ITM

1 × Pulse

Nominal

Discharge

Current

In

Varistor

Voltage at

1mA Test

Current

V

N(DC)

Min

V

N(DC)

Max

Maximum

Clamping

Voltage

8/20μs

Vc I

Typical

Capacitance

f = 1MHz

PK

(V) (V) (J) (A) (A) (V) (V) (A) (pF)

SMOV34S111MP

SMOV34S111NP

SMOV34S131MP

SMOV34S131NP

SMOV34S151MP

SMOV34S151NP

SMOV34S181MP
SMOV34S181NP

SMOV34S251MP
SMOV34S251NP

SMOV34S271MP

SMOV34S271NP

SMOV34S301MP

SMOV34S301NP

SMOV34S321MP

SMOV34S321NP

SMOV34S421MP

SMOV34S421NP

SMOV34S461MP

SMOV34S461NP

SMOV34S511MP

SMOV34S511NP

SMOV34S551MP

SMOV34S551NP

SMOV34S621MP

SMOV34S621NP

SMOV34S751MP

SMOV34S751NP

Average power dissipation of transients should not exceed 2.0 watts
Same ratings and specifications apply to Non Isolated Monitored Switch alternative design. Replace "M" with "N" in the part number. e.g.: SMOV34S111NP.
Refer to Part Number System at the end of this document.

115 150 280 40000 20000 163 202 305 200 11500

130 175 310 40000 20000 184 228 345 200 10000

150 200 360 40000 20000 212 268 405 200 8000

180 240 400 40000 20000 254 312 488 200 6800

250 320 490 40000 20000 354 429 650 200 5000

275 350 550 40000 20000 389 473 730 200 4500

300 385 590 40000 20000 433 528 780 200 4050

320 420 640 40000 20000 462 561 830 200 3800

420 560 910 40000 20000 610 748 1130 200 3000

460 610 960 40000 10000 642 783 1188 200 2800

510 675 960 40000 10000 735 910 1350 200 2500

550 700 965 40000 10000 770 939 1415 200 2250

62 0 80 0 1010 40000 10000 900 1100 1625 200 2100

750 970 1200 40000 10000 1080 1320 2000 200 1800

C

SMOV34S Varistor Series

244

Revised: May 8, 2013

Please refer to www.littelfuse.com/series/smov34s.html for current information.

Specifications are subject to change without notice.

© 2013 Littelfuse, Inc.

Varistor Products

Thermally Protected Varistors > SMOV34S Series

Thermal Characteristics

10

1

Current (A)

0.1

Figure 1

110100

Time (secs)

Typical

10 A

5 A

2.5 A

0.5 A

Peak Current & Energy Derating Curve

100

80

60

40

20

PERCENT OF RATED VALUE

0

-45506070

Figure 2

AMBIENT TEMPERATURE (ºC)

80

90 100 110 12 0 1 30

For applications exceeding 75ºC ambient temperature, the peak
surge current and energy ratings must be reduced as shown.

Pulse Rating Curve

50,000

20,000

10,000

SURGE CURRENT (A)

Figure 3

1

2

15

5,000

2

10

2,000

3

10

1,000

4

10

500

200

100

50

INDEFINITE

20

10

20 100 1,000 10,000

IMPULSE DURATION ( µs)

5

10

SMOV34

6

10

SMOV34S V–I Characteristic Curves for SMOV34S Varistor

10000

Maximum Clamping Voltage
SMOV34S series

Voltage ­VOLTS

V571

V551

V511

1000

V481

V441

V421

100

Figure 4

© 2013 Littelfuse, Inc.
Specifications are subject to change without notice.
Please refer to www.littelfuse.com/series/smov34s.html for current information.

1mA 10mA 100mA 1A 10A 100A 10000A 100000A

Current - AMPS

V391 V351 V331 V321 V271 V251 V201 V181

Revised: May 8, 2013

245

TA = -45 C to 75C

V681V661

V751

V301

1000A

V141

V151

V131

V 111

SMOV34S Series

HI–ENERGY MOV’S

SMOV34S Varistor Series

Wave Solder Profile

TEMPERATURE

(

C)

TEMPERATURE

(ºC)

Varistor Products

Thermally Protected Varistors > SMOV34S Series

Because the SMOV34S Series varistors contain a thermal protec­tion device, care must be taken when soldering the devices into
place. Two soldering methods are possible. Firstly, hand soldering:

Non Lead–free Profile

300

250

º

200

150

100

50

0

00.5 11.5 22.5 33.5 4

Figure 5 Figure 6

Maximum Wave 240C

TIME(MINUTES)

Physical Specifications

Lead Material Tin–plated Copper

Soldering
Characteristics

Insulating Material

Device Labeling

Solderability per MIL–STD–202,
Method 208E

Cured, flame retardant epoxy polymer
meets UL94V–0 requirements.

Marked with LF, part identifier, and
date code

It is recommended to heat–sink the leads of the device. Secondly,
wave–soldering: It is critically important that all preheat stage and
the solder bath temperatures are rigidly controlled.

Lead–free Profile

Environmental Specifications

Operating/Storage
Temperature

Humidity Aging

Thermal Shock

Solvent Resistance MIL–STD–202, Method 215F

300

Maximum Wave 260C

250

200

150

100

50

0

00.511.522.533.54

TIME(MINUTES)

-45°C to +75°C/

-45°C to +85°C

+75°C, 85% RH, 1000 hours
+/-10% voltage

+75°C to -40°C 5 times
+/-10% voltage

Moisture Sensitivity Level 1, J–STD–020C

Part Numbering System

SMOV 34 S 321 N P

DEVICE FAMILY

Littelfuse Thermally Self Protected MOV

DISC SIZE (mm)

34mm

CERAMIC SHAPE

S: Square

V

M(AC)RMS

115V to 750V

Part Marking System

UL Recognized

Component Mark

Production Site Code

Littelfuse Mark

Part Number

Production Date Dode

(Year and Week)

LF9

SMOV34S321MP

1148

M:With Isolated Monitored Switch
N: Non Isolated Monitored Switch Design

P: Lead-Free and RoHS compliant

SMOV34S Varistor Series

246

Revised: May 8, 2013

Please refer to www.littelfuse.com/series/smov34s.html for current information.

Specifications are subject to change without notice.

© 2013 Littelfuse, Inc.

Varistor Products

Thermally Protected Varistors > SMOV34S Series

Lead ConfigurationDevice Dimension

41Max

LF 9

SMOV34S321MP

44.5Max

10Min

11.0±0.5

2.5±0.3

114 8

1.4±0.2

10Min

3*0.6±0.2

6.0±0.2

21.5±0.2

6.5±2.2

Application Example

1.2±0.3

0.3±0.2

0.5±0.2

Thermal
disconnect

P1

20Max

LF9

SMOVXXS321MP

1209

3.6±0.3

S2 S3 S1

P2

6.0±0.2

S2 S3 S1

P2

Galvanic isolation

* LED is off when the product is normal(S1,S3 connected),

LED is on when the product disconect opens(switch change
status; S2,S3 connected as shown by dotted line ).

S1 ON

P1

Thermal
disconnect

MOV

P1

P1

P2

Primary side

LED

R

Galvanic isolation

S1 ON

(Normal Close)

S3 Common

S2 OFF
(Normal open)

Secondary side

S3 Common

MOV

S2 OFF

Primary side

P2

Note: EXAMPLE ONLY - Connection to S2-S3 and S1-S3
depends on customer indication circuit and can vary.

Secondary side

To Protected Circuit

Switch Specification

SMOV Switch Voltage DC Current (Amps) Contact Resistance Max. Insulation Resistance Min.

Switch 12V 0.1A 70m 100M 500VAC

© 2013 Littelfuse, Inc.
Specifications are subject to change without notice.
Please refer to www.littelfuse.com/series/smov34s.html for current information.

247

Revised: May 8, 2013

Dialectric Strength

0.5mA/Minute

SMOV34S Series

HI–ENERGY MOV’S

SMOV34S Varistor Series

Term Definitions

Varistor Products

Thermally Protected Varistors > SMOV34S Series

Rated AC Voltage (V

M(AC)RMS

) – MCOV

This is the maximum continuous sinusoidal RMS voltage
that may be applied. This voltage may be applied at any
temperature up to the maximum operating temperature of
the device.

Maximum Non-Repetitive Surge Current (ITM)

This is the maximum peak current which may be applied
for a single 8/20µs impulse, with rated line voltage also
applied, without causing device failure. The pulse can
be applied to the device in either polarity with the same
confidence factor.

Nominal Discharge Current (IN)

Peak value of the current, selected by the manufacturer,
through the SPD having a current waveshape of 8/20µs
where the SPD remains functional after 15 surges.

Voltage Protection Rating (VPR)

A rating selected from a list of preferred values as given
in UL 1449 and assigned to each mode of protection. The
value of VPR is determined as the nearest highest value
taken from UL 1449 to the measured limiting voltage
determined during the transient-voltage surge suppression
test using the combination wave generator at a setting of
6kV, 3kA.

UL 1449

An Underwriters Laboratory standard covering the safety
requirements for Surge Protective Devices intended for
permanently connected, cord-connected and direct plug-in
applications.

Limited Current Abnormal Over-voltage Test

An AC over-voltage condition applied to a Surge Protective
Device according to UL 1449, Section 39.4. The short circuit
current is limited by series connected resistors to 10A,
5A, 2.5A, 0.5A and 0.125A. The condition is maintained
for 7 hours or until the device under test is disconnected
from the AC supply or the current or temperature reaches
equilibrium.

Maximum Non-Repetitive Surge Energy (WTM)

This is the maximum rated transient energy which may be
dissipated for a single current pulse at a specified impulse
duration, with the rated RMS voltage applied, without
causing device failure.

Nominal Voltage (V

N(DC)

)

This is the voltage at which the device changes from the
off (standby state) to the on (clamping state) and enters
its conduction mode of operation. The voltage value is
usually characterised at the 1mA point and has a specified
minimum and maximum voltage range.

SMOV34S Varistor Series

248

Revised: May 8, 2013

Please refer to www.littelfuse.com/series/smov34s.html for current information.

Specifications are subject to change without notice.

© 2013 Littelfuse, Inc.