Littelfuse SM20 Varistor Series User Manual
Varistor products, Sm20 varistor series, Surface mount varistors > sm20 series
© 2014 Littelfuse, Inc.
81
Revised: February 6, 2014
Varistor Products
SM20 Series Varistor
Surface Mount Varistors > SM20 Series
Specifications are subject to change without notice.
Please refer to www.littelfuse.com/series/sm20.html for current information.
SM20 S
eries
Description
The Littelfuse 20mm SMD Series is a surface-mount
metal oxide varistor device, for use in applications
requiring hi-energy / transient current capability.
The AC rated parts are designed to operate
continuously across AC power lines. The DC rated
parts are suitable for Automotive applications. The
series comprises a Nylon molded package with folded
tin plated metal leads for soldering to board.
The SMD Series is based on radial 20mm internal
varistor element with similar characteristics to
the Littelfuse LA / ZA series of varistors.
Features
• DC Voltage Rating
26 - 420VDC
• AC Voltage Rating
175 - 320AC
• No De-Rating up
to 85°C ambient
• Lead-Free, Halogen-
Free and RoHS
Compliant
• Low voltage
devices specified
for automotive load
dump energy
• Available in "waffle"
tray packaging
Agency Approvals
Absolute Maximum Ratings
• For ratings of individual members of a series, see Device Ratings and Specifications chart
Agency
Agency File Number
E320116
Continuous
SM20 Series
Units
Steady State Applied Voltage:
AC Voltage Range (V
M(AC)RMS
)
20 to 320
V
DC Voltage Range (V
M(DC)
)
26 to 420
V
Transients:
Peak Pulse Current (I
TM
) 8/20µs Current Wave, Single Pulse
up to 6500
A
Single Pulse Energy Capability (W
TM
) 10/1000µs Current Wave
165
J
Load Dump Energy Capability (td>=30ms)
160
J
Operating Ambient Temperature Range (T
A
)
-40 to +85
O
C
Storage Temperature Range (T
STG
)
-55 to +125
O
C
Temperature Coefficient (a
V
) of Clamping Voltage (V
C
) at Specified Test Current
<0.01
%/
O
C
Hi-Pot Encapsulation (COATING Isolation Voltage Capability)
(Dielectric must withstand indicated DC voltage for one minute per MIL-STD 202, Method 301)
2500
V
COATING Insulation Resistance
1000
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.
SM20 Varistor Series
RoHS