Varistor Products SM7 Varistor Series

Varistor Products
Surface Mount Varistors > SM7 Series
SM7 Varistor Series
RoHS
Description
The series comprises a Nylon molded package with
tin plated lead frame for soldering to board. The
surface mount SM7 Series is based on radial 7mm
internal varistor element with similar characteristics
to the Littelfuse LA / ZA series of varistor.
Features
Agency Approvals
Agency
Agency File Number
E320116
• Electrical equivalent
to leaded types
LA/ZA series
•
Good solderability
•
Available in tape
and reel
•
AC Voltage Rating
115 to 510VAC rms
•
Application of AC
power meters
•
No De-Rating up
to 85°C ambient
Absolute Maximum Ratings
• For ratings of individual members of a series, see Device Ratings and Specifications chart
Continuous
SM7 Series
Units
AC Voltage Range (VM(AC)RMS)
115 to 510
V
DC Voltage Range (VM(DC))
153 to 675
V
1200
A
Steady State Applied Voltage:
Transients:
Peak Pulse Current (ITM)
For 8/20μs Current Wave (See Figure 2)
Single Pulse Energy Range
For 10/1000μs Current Wave (WTM)
10 to 40
J
Operating Ambient Temperature Range (TA)
-40 to +85
O
Storage Temperature Range (TSTG)
-55 to +125
O
C
C
Temperature Coefficient (aV) of Clamping Voltage (VC) at Specified Test Current
<0.01
%/OC
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.
© 2013 Littelfuse, Inc.
Specifications are subject to change without notice.
Please refer to www.littelfuse.com/series/sm7.html for current information.
75
Revised: May 8, 2013
SM7 Series Varistor
SM7 Series
The Littelfuse SM7 Series is a plastic-encapsulated
surface-mount metal oxide varistor (MOV) transient
voltage surge suppressor that is designed to be
operated continuously across AC power lines.
Varistor Products
Surface Mount Varistors > SM7 Series
SM7 Series Ratings & Specifications
Maximum Rating (85°C)
Continuous
Transient
Part
Number
V115SM7
V130SM7
V140SM7
V150SM7
V175SM7
V230SM7
V250SM7
V275SM7
V300SM7
V320SM7
V385SM7
V420SM7
V460SM7
V480SM7
V510SM7
VRMS
VDC
VM(AC)
(V)
115
130
140
150
175
230
250
275
300
320
385
420
460
480
510
VM(DC)
(V)
153
175
180
200
225
300
330
369
405
420
505
560
615
640
675
Specifications (25°C)
Maximum
Varistor Voltage
Clamping
at
1mA
DC
Energy
Peak Current
Voltage
Test
Current
10 x 1000μs
8 x 20μs
8 x 20 μs
WTM
ITM
VNOM Min VNOM Max
VC
IPK
(J)
(A)
(V)
(V)
(V)
(A)
10
1200
162
198
300
10
11
1200
184
228
340
10
12
1200
198
242
360
10
13
1200
212
268
395
10
15
1200
247
303
455
10
20
1200
324
396
595
10
21
1200
354
429
650
10
23
1200
389
473
710
10
25
1200
420
517
775
10
25
1200
462
565
850
10
27
1200
558
682
1025
10
30
1200
610
748
1120
10
37
1200
640
790
1190
10
35
1200
670
825
1240
10
40
1200
735
910
1200
10
Typical
Capacitance
f = 1MHz
C
(pF)
200
180
160
150
130
100
90
80
70
65
60
55
55
50
45
NOTE: SM7 series devices are recognized under UL file # E320116
SM7 Series Varistor
76
Revised: May 8, 2013
© 2013 Littelfuse, Inc.
Specifications are subject to change without notice.
Please refer to www.littelfuse.com/series/sm7.html for current information.
Varistor Products
Surface Mount Varistors > SM7 Series
Peak Pulse Current Test Waveform for Clamping Voltage
PERCENT OF PEAK VALUE Test
For applications exceeding 85ºC ambient temperature, the peak
surge current and energy ratings must be reduced as shown below
PERCENT OF RATED VALUE
100
90
80
70
60
50
40
100
50
0
t
O1
TIM E
t1
30
20
t
10
0
-55
50
60
70
80
90
100
110
120
130
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
140 150
AMBIENT TEMPERATURE ( oC)
V-I Limit Curves
Pulse Rating Curves
V510SM7
V480SM7
V460SM7
V420SM7
V385SM7
V320SM7
V300SM7
V250SM7
V230SM7
V210SM7
V190SM7
V175SM7
V150SM7
V140SM7
V130SM7
V115SM7
Voltage(V)
1500
1000
500
10000
0
0.001
1
1000
Surge Current (A)
2000
2
104
10
105
2
100
10
103
106
10
0.01
0.1
1
10
100
1000
Current(A)
1
NOTE: If pulse ratings are exceeded, a shift of VN(DC) (at specified current) of more than
±10% could result. This type of shift, which normally results in a decrease of VN(DC), may
result in the device not meeting the original published specifications, but it does not prevent
the device from continuing to function, and to provide ample protection.
© 2013 Littelfuse, Inc.
Specifications are subject to change without notice.
Please refer to www.littelfuse.com/series/sm7.html for current information.
77
Revised: May 8, 2013
10
100
1000
10000
Impulse Duration (μs)
SM7 Series Varistor
SM7 Series
Peak Current, Energy and Power Derating Curve
Varistor Products
Surface Mount Varistors > SM7 Series
Lead (Pb) Soldering Recommendations
The principal techniques used for the soldering of
components in surface mount technology are IR Re-flow
and Wave soldering. Typical profiles are shown on the right.
Reflow Solder Profile
250
The terminals of SM7 series devices are tin plated copper,
and the recommended solder is 62/36/2 (Sn/Pb/Ag), 60/40
(Sn/Pb) or 63/37 (Sn/Pb). Littelfuse also recommends an
RMA solder flux.
MAXIMUM TEMPERATURE
230°C
TEMPERATURE °C
200
Wave soldering is the most strenuous of the processes.
To avoid the possibility of generating stresses due to
thermal shock, a preheat stage in the soldering process
is recommended, and the peak temperature of the solder
process should be rigidly controlled.
40-80
SECONDS
ABOVE 183°C
150
RAMP RATE
<2°C/s
100
PREHEAT DWELL
50
PREHEAT ZONE
0
When using a reflow process, care should be taken to
ensure that the SM7 chip is not subjected to a thermal
gradient steeper than 4 degrees per second; the ideal
gradient being 2 degrees per second. During the soldering
process, preheating to within 100 degrees of the solder's
peak temperature is essential to minimize thermal shock.
0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
TIME (MINUTES)
Wave Solder Profile
300
Once the soldering process has been completed, it is
still necessary to ensure that any further thermal shocks
are avoided. One possible cause of thermal shock is hot
printed circuit boards being removed from the solder
process and subjected to cleaning solvents at room
temperature. The boards must be allowed to cool gradually
to less than 50ºC before cleaning.
MAXIMUM WAVE 260°C
TEMPERATURE °C
250
200
150
SECOND PREHEAT
100
FIRST PREHEAT
50
0
0.0
0.5
1.0
1.5
2.0
2.5
3.0
TIME (MINUTES)
3.5
4.0
4.5
Lead–free (Pb-free) Soldering Recommendations
The terminals of SM7 series devices are tin plated copper,
and the recommended Lead-free solder is 96.5/3.0/0.5
(SnAgCu) with an RMA flux, though there is a wide
selection of pastes and fluxes available that should be
compatible.
Lead–free Re-flow Solder Profile
300
MAXIMUM TEMPERATURE 250˚C,
TIME WITHIN 5˚C OF PEAK
20 SECONDS MAXIMUM
Note: the Lead–free paste, flux and profile were used for
evaluation purposes by Littelfuse, based upon industry
standards and practices. There are multiple choices of all
three available, it is advised that the customer explores the
optimum combination for their process as processes vary
considerably from site to site.
SM7 Series Varistor
78
Revised: May 8, 2013
TEMPERATURE °C
250
The reflow profile must be constrained by the maximums
in the Lead–free Reflow Profile. For Lead–free Wave
soldering, the Wave Solder Profile still applies.
RAMP RATE
<3˚C/s
200
60 - 150 SEC
> 217˚C
150
100
PREHEAT ZONE
50
0
0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
TIME (MINUTES)
© 2013 Littelfuse, Inc.
Specifications are subject to change without notice.
Please refer to www.littelfuse.com/series/sm7.html for current information.
Varistor Products
Surface Mount Varistors > SM7 Series
Part Numbering System
Product Dimensions
11.5±0.3
V 275 SM7
8.3±0.3
0.3 max
4.0±0.3 for
For “VARISTOR”
V115SM7-V175SM7
VM(AC)
(Three digits -- 115V to 510V)
6.0±0.3 for
V230SM7-V510SM7
SM7 SERIES
SM7 Series
3.0±0.3
1.5±0.3
3.5 All dimensions shown
6.5
in milimeters
13.1
Soldering Pad Layout
Tape & Reel Specifications
mm
W
16.00±0.30
T
0.40±0.05
E
A0
11.80±0.10
F
Carrier Tape
B0
8.60±0.10
K0
6.80±0.10
E
1.75±0.10
F
7.50±0.10
P0
B
D1
B
3.60
W
A
B0
D0
A
5°
P1
P2
T
A0
11.30
10°
5°
6.2
K0
2
B-B
P0
4.00±0.10
P1
16.00±0.10
P2
2.00±0.10
D0
ø1.50 +0.10/-0
D1
ø1.50 +0.10/-0
NOTES:
1) All dimensions per EIA-481-c
2) 10 pitches cumulative tolerance on tape ±0.20mm
3) Quantity per 13 inch (330 mm) reel: 600 pcs
A-A
Plastic Reel
DETAIL H
Ø
2±0.5
.2
±0
13
±0.8
Ø330
Ø100
Ø21
R1
16.5
120°
DETAIL H
21.5±0.4
© 2013 Littelfuse, Inc.
Specifications are subject to change without notice.
Please refer to www.littelfuse.com/series/sm7.html for current information.
79
Revised: May 8, 2013
SM7 Series Varistor