Littelfuse SMOV25S Varistor Series - Manual (Page 6)

© 2013 Littelfuse, Inc. 242
Revised: May 8, 2013
Varistor Products
Specifications are subject to change without notice.
Please refer to www.littelfuse.com/series/smov25s.html for current information.
SMOV25S Varistor Series
Thermally Protected Varistors > SMOV25S 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 (I
TM
)
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 (I
N
)
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 (V
PR
)
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 (W
TM
)
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.
Term Definitions
Part Numbering System
SMOV 25 S 321 N P
DEVICE FAMILY
Littelfuse Thermally Self Protected MOV
DISC SIZE (mm)
25mm
CERAMIC SHAPE
S: Square
115V to 750V
V M(AC)RMS
M:With Isolated Monitored Switch
N: Non Isolated Monitored Switch Design
P: Lead-Free and RoHS compliant
LF9
SMOV25S321MP
1148
UL Recognized
Component Mark
Production Site Code
Littelfuse Mark
Part Number
Production Date Dode
(Year and Week)
Part Marking System