Resettable PTCs
250
w w w . l i t t e l f u s e . c o m
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.
AGENCY APPROVALS:
Recognized under the Components Program
of Underwriters Laboratory and the Component Acceptance Program of
CSA. TUV approved.
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.
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:
ENVIRONMENTAL SPECIFICATIONS:
Passive Aging:
85C, 1000 Hours.
Humidity Aging:
85C, 85% R.H., 100 hours.
Thermal Shock:
85C / 40C, 20 times.
125C / 55C, 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:
40C to 85C Devices should
remain in sealed bags prior to use.
Part
Reel
Packaging
Number
Quantity Suffix
3425L Series
1500
DR
-40
-30
-20
-10
0
10
20
30
40
50
60
70
80 85
0
90
80
70
60
50
40
30
20
10
100
130
120
110
140
150
160
Temperature (
C)
Percentage of Rated Current
Rerating Curve for 3425L Series
Surface Mount PTC
3425L Series
Resettable PTCs
251
w w w . l i t t e l f u s e . c o m
6
RESETT
ABLE PTCs
Dimensions (Inches)
MARKING
B
F
D
E
C
0.51-0.89
(.020-.035)
3.05
(.120)
0.635
(.025)
0.635
(.025)
A
Recommended Pad Layout (Inches)
All dimensions are nominal.
Series
A
B
C
D
E
F
3425L 6.70 max 9.50 max 3.68 4.572 2.29 10.67
(.264 max.) (.374 max.) (.145) (.180) (.090) (.420)
RECOMMENDED REFLOW CONDITIONS:
(IR, Forced Air Convection, Vapor Phase)
Devices are not designed to be wave soldered.
Catalog
I
hold
I
trip
V
max
I
max
P
d
max.
Current
Time
R
IL
R
AT
Number
(A)
(A)
(Vdc)
(A)
(W)
(A)
(Sec)
(
)
(
)
3425L150
1.50
3.0
15
40
1.9 8.0
5.0
0.060
0.25
3425L200
2.00
4.0
15
40
1.9 8.0 12.0
0.050
0.15
3425L250
2.50
5.0
15
40
1.9 8.0 25.0
0.035
0.10
3425L300
3.00
6.0
6
40
1.9 8.0 32.0
0.020
0.06
Maximum Time
To Trip
Ihold
=
Hold Current: maximum current device will sustain for 4 hours without tripping in 20C still air.
Itrip
=
Trip Current: minimum current at which the device will trip in 20C still air.
Vmax
=
Maximum voltage device can withstand without damage at rated current (Imax)
Imax
=
Maximum fault current device can withstand without damage at rated voltage (Vmax)
Pd
=
Power dissipated from device when in the tripped state at 20C still air.
RIL
=
Minimum resistance of device in initial (un-soldered) state.
RAT
=
Maximum measured resistance in the non-tripped state 1 hour after reflow with reflow conditions of 260C for 20 sec.
CAUTION: Operation beyond the specified ratings may result in damage and possible arcing and flame.
ORDERING INFORMATION:
Resistance
1.50A
2.00A 2.50A 3.00A
100
10
1
0.1
100
10
1
0.1
0.01
CURRENT IN AMPERES
TIME IN SECONDS
Average Time Current Curves
PDF 
ZIP