The CA Series of transient surge suppressors are industrial
high-energy disc varistors (MOVs) intended for special
applications requiring unique electrical contact or packaging
methods provided by the customer. The electrode finish
of these devices is solderable and can also be used with
pressure contacts. Discs of the same diameter may be
stacked.
This series of industrial disc varistors are nominal 60mm
diameter, with disc thickness ranging from 2.7mm to
32mm. The voltage range is 250V to 2800 V
(AC)RMS
.
For information on soldering considerations, refer to EC637
"Recommendations for Soldering Terminal Leads to MOV
Varistor Discs."
Features
• Standard disc size
nominal 60mm
diameter
• Discs have edge
passivation insulation
• High peak pulse
current range
50000A to 70000A
• Very high–energy
capability W
tm
880J to 10000J
Absolute Maximum Ratings
• For ratings of individual members of a series, see Device Ratings and Specifications chart
ContinuousCA SeriesUnits
Steady State Applied Voltage:
AC Voltage Range (V
DC Voltage Range (V
Transient:
Peak Pulse Current (ITM)
For 8/20μs Current Wave(See Figure 2)20,000 to 70,000A
Single-Pulse Energy Range
For 2ms Current Square Wave (W
Operating Ambient Temperature Range (T
Storage Temperature Range (T
Temperature Coefficient (V) of Clamping Voltage (V
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.
NOTE: Average power dissipation of transients should not exceed 2.5W for CA60 discs.
60
60
60
60
60
60
110 0
140 0
170 0
2000
2400
2800
140 0
1750
2150
2500
3000
3500
3800
5000
6000
7500
8800
10000
70000
70000
70000
70000
70000
70000
1620
2020
2500
2970
3510
4230
1800
2200
2700
3300
3900
4700
2060
2550
3030
3630
4290
5170
Max Clamping
Volt Vc at 200A
Current
(8/20μs)
2940
3600
4300
5200
6200
74 0 0
Typical
Capacitance
2200
1800
150 0
120 0
1000
800
Power Dissipation Ratings
100
90
80
70
60
50
40
30
20
PERCENT OF RATED VALUE
10
0
-55 50 60 70 80 90 100 110 120 130 140 150
Figure 1
AMBIENT TEMPERATURE (
Should transients occur in rapid succession, the average power
dissipation result is the energy (watt-seconds) per pulse times
the number of pulses per second. The power so developed must
be within the specifications shown on the Device Ratings and
Specifications table for the specific device. Furthermore, the
operating values need to be derated at high temperatures as
shown in above. Because varistors can only dissipate a relatively
small amount of average power they are, therefore, not suitable
for repetitive applications that involve substantial amounts of
average power dissipation.
o
C)
Peak Pulse Current Test Waveform
100
90
50
10
O
1
Figure 2
01 = Virtual Origin of Wave
T = Time from 10% to 90% of Peak
T1 = Rise Time = 1.25 x T
T2 = Decay Time
Example - For an 8/20 μs Current Waveform:
8μs = T1 = Rise Time
20μs = T2 = Decay Time
T
T
1
T
2
TIME
CA Varistor Series
182
Revised: May 8, 2013
Please refer to www.littelfuse.com/series/ca.html for current information.
Specifications are subject to change without notice.
NOTE: If pulse ratings are exceeded, a shift of V
+/-10% could result. This type of shift, which normally results in a decrease of V
result in the device not meeting the original published specifications, but does not prevent
the device from continuing to function, and to provide ample protection.
The standard CA Series is supplied with passivation
layer around the outside perimeter of the disc forming
an electrical insulator as detailed in the dimensional
drawing. For other options contact factory. (See Ordering
Information)
Encapsulated Recommendations
After lead attachment, the disc/lead assembly may be
coated or encapsulated in a package to provide electrical
insulation and isolation from environmental contamination
as required by the application. Coating/Filler materials for
containers may include silicones, polyurethanes, and some
epoxy resins. Materials containing halogens, sulfides, or
alkalines are not recommended.
Stacking and Contact Pressure Recommendations
When applications require the stacking of CA60 discs,
or when an electrical connection is made by pressure
contacts, the pressure applied to the CA60 disc electrode
surface should be minimum 2.2kgs (5 pounds) and
maximum
4N/CM2 (5.7LBs/IN2).
Part Numbering System
Electrode Metallization
CA60 discs are supplied as standard with sintered Silver
electrodes. For other available options please contact
Littelfuse.
Recommended Reflow Temperature Profile
250
200
C)
o
150
100
TEMPERATURE (
50
0
0100 200 300 400 500 600 700 800 900
TIME (SEC)
Packaging and Shipping
VARISTOR DESIGNATOR
MAX AC
(FIRST SIGNIFICANT DIGITS) V
V
M(AC)
SERIES DESIGNATOR
DISC SIZE (mm) DIAMETER
WORKING VOLTAGE
RMS
VOLTAGE DECADE MULTIPLIER
V 25 1 CA 60
M(AC)
The CA Series is supplied in bulk for shipment. Discs are
packaged in compartmentalized cartons to protect from
scratching or edge-chipping during shipment.
No branding or any other type of marking appears on the
CA disc itself.
CA60 discs are supplied as standard with sintered Silver
electrodes and glass passivation. For other available
options please contact factory.