Resettable PTCs
Surface Mount PTC
3425L Series
®
®
• The 3425L Series Resettable devices utilize a unique polymer-based,
Positive Temperature Coefficient (PTC) material to protect electrical
circuits against overcurrent conditions.
• In normal operation, the 3425L Series PTC has many conductive paths
and a very low resistance. In an overcurrent condition, the temperature
of the polymer material rises. This dramatically reduces the conductive
paths resulting in an immediate rise in resistance. In this condition, the
device provides circuit protection by significantly limiting the flow of
current. However, once the cause of the initial overcurrent condition is
eliminated, the 3425L Series PTC cools down and resets to a low
resistance value permitting the normal current flow to resume.
• The 3425L Series are surface mountable.
ENVIRONMENTAL SPECIFICATIONS:
Passive Aging:
85°C, 1000 Hours.
Humidity Aging:
85°C, 85% R.H., 100 hours.
Thermal Shock:
85°C / –40°C, 20 times.
125°C / –55°C, 10 times.
Vibration:
MIL-STD 202, Method 201. No resistance change.
Mechanical Shock:
MIL-STD-202, Method 213 test condition I
(100 g’s, 6 sec.).
Operating/Storage Temperature:
–40°C to 85°C Devices should
remain in sealed bags prior to use.
AGENCY APPROVALS:
Recognized under the Components Program
of Underwriters Laboratory and the Component Acceptance Program of
CSA. TUV approved.
Rerating Curve for 3425L Series
160
150
140
130
120
110
100
90
80
70
60
50
40
30
20
10
0
-40
-30
-20
-10
0
10
20
30
Temperature (°C)
40
50
60
70
80 85
AGENCY FILE NUMBERS:
UL E183209, CSA LR 108832
PHYSICAL SPECIFICATIONS:
Materials:
Terminal Material: Tin Plated Brass to MIL-T-10727B
Solderability:
Meets EIA specification RS186-9E and IPC/EIA
J-STD-002, and IPC/EIA J-STD-001.
Percentage of Rated Current
Device Labeling:
Device is marked with the letter ‘L’, amperage rating
and date code.
Packaging:
Packaged in tape and reel carrier per EIA 481-2 standard
Standard reel quantities:
Part
Number
3425L Series
Reel
Quantity
1500
Packaging
Suffix
DR
250
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Resettable PTCs
Surface Mount PTC
3425L Series
Dimensions (Inches)
B
D
A
100
MARKING
E
F
3.05
(.120)
0.635
(.025)
0.635
(.025)
C
0.51-0.89
(.020-.035)
10
Series
3425L
A
6.70 max
(.264 max.)
B
9.50 max
(.374 max.)
C
D
E
F
3.68 4.572 2.29 10.67
(.145) (.180) (.090) (.420)
TIME IN SECONDS
1
RECOMMENDED REFLOW CONDITIONS:
(IR, Forced Air Convection, Vapor Phase)
Devices are not designed to be wave soldered.
1.50A
2.00A
2.50A
3.00A
Recommended Pad Layout (Inches)
All dimensions are nominal.
Average Time Current Curves
6
0.1
0.01
0.1
1
10
CURRENT IN AMPERES
100
ORDERING INFORMATION:
Maximum Time
To Trip
Catalog
Number
I
hold
(A)
I
trip
(A)
V
max
(Vdc)
I
max
(A)
P
d
max.
(W)
Current
(A)
Time
(Sec)
R
IL
(Ω)
Resistance
R
AT
(Ω)
3425L150
3425L200
3425L250
3425L300
Ihold
Itrip
Vmax
Imax
Pd
RIL
RAT
=
=
=
=
=
=
=
1.50
2.00
2.50
3.00
3.0
4.0
5.0
6.0
15
15
15
6
40
40
40
40
1.9
1.9
1.9
1.9
8.0
8.0
8.0
8.0
5.0
12.0
25.0
32.0
0.060
0.050
0.035
0.020
0.25
0.15
0.10
0.06
Hold Current: maximum current device will sustain for 4 hours without tripping in 20°C still air.
Trip Current: minimum current at which the device will trip in 20°C still air.
Maximum voltage device can withstand without damage at rated current (Imax)
Maximum fault current device can withstand without damage at rated voltage (Vmax)
Power dissipated from device when in the tripped state at 20°C still air.
Minimum resistance of device in initial (un-soldered) state.
Maximum measured resistance in the non-tripped state 1 hour after reflow with reflow conditions of 260°C for 20 sec.
CAUTION: Operation beyond the specified ratings may result in damage and possible arcing and flame.
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251
Programming Basics
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