121
Revised: June 4, 2010
POLYFUSE® Resettable PTCs
© 2010 Littelfuse, Inc
POLYFUSE® Resettable PTCs
ST Series
Specifications are subject to change without notice.
Please refer to www.littelfuse.com/series/ST.html for current information.
ST Series
Axial Lead Battery Strap Type > ST Series
ST Series
The new ST Series device provides reliable, noncycling
protection against overcharging and short circuits events
for rechargeable battery cells where resettable protection
is desired.
Electrical Characteristics
Part Number I hold
(A)
I trip
(A)
V max
(Vdc)
I max
(A)
P d
max.
(W)
Maximum Time
To Trip Resistance Agency
Approvals
Current
(A)
Time
(Sec.)
R min
(Ω)
R typ
(Ω)
R 1max
(Ω)
15ST120 1.2 2.7 15 100 1.2 6.00 5.00 0.085 0.160 0.220 XX
15ST120S 1.2 2.7 15 100 1.2 6.00 5.00 0.085 0.160 0.220 XX
15ST175 1.75 3.8 15 100 2.5 8.75 5.00 0.050 0.090 0.120 XX
15ST175S 1.75 3.8 15 100 2.5 8.75 5.00 0.050 0.090 0.120 XX
30ST200 2.00 4.4 30 100 1.9 10.00 4.00 0.030 0.060 0.100 XX
30ST350 3.50 6.3 30 100 2.5 20.00 3.00 0.017 0.031 0.050 XX
30ST420 4.20 7.6 30 100 2.9 20.00 6.00 0.012 0.024 0.040 XX
I hold = Hold current: maximum current device will pass without tripping in 20°C still air.
I trip = Trip current: minimum current at which the device will trip in 20°C still air.
V max = Maximum voltage device can withstand without damage at rated current (I max)
I max = Maximum fault current device can withstand without damage at rated voltage (Vmax)
P d = Power dissipated from device when in the tripped state at 20°C still air.
R min = Minimum resistance of device in initial (un-soldered) state.
R typ = Typical resistance of device in initial (un-soldered) state.
R 1max = Maximum resistance of device at 20°C measured one hour after tripping or reflow
soldering of 260°C for 20 sec.
Caution: Operation beyond the specified rating may result in damage and possible arcing
and flame.
Description
Features
Applications
• RoHS compliant and
lead–free
• Weldable Nickel terminals
• Low resistance
• Provides overcurrent
protection at 125°C trip
temperature
• Rechargeable battery cell
protection
Agency Approvals
AGENCY AGENCY FILE NUMBER
E183209
R50119583
Items with S at end of part number identify items with slit lead option. See Dimension Drawing and Part Ordering Number System sections of this document for more information.
122
Revised: June 4, 2010
POLYFUSE® Resettable PTCs
© 2010 Littelfuse, Inc.
ST Series
Specifications are subject to change without notice.
Please refer to www.littelfuse.com/series/ST.html for current information.
Axial Lead Battery Strap Type > ST Series
Ambient Operation Temperature
-40°C -20°C 0°C 23°C 40°C 50°C 60°C 70°C 85°C
Part Number Hold Current (A)
15ST120 1.90 1.70 1.50 1.20 1.00 0.90 0.80 0.70 0.50
15ST120S 1.90 1.70 1.50 1.20 1.00 0.90 0.80 0.70 0.50
15ST175 2.50 2.30 2.00 1.75 1.50 1.30 1.20 1.10 0.90
15ST175S 2.50 2.30 2.00 1.75 1.50 1.30 1.20 1.10 0.90
30ST200 3.20 2.80 2.50 2.00 1.70 1.60 1.40 1.20 0.90
30ST350 5.40 4.80 4.30 3.50 3.00 2.80 2.50 2.20 1.70
30ST420 6.40 5.70 5.10 4.20 3.60 3.30 3.00 2.60 2.10
Temperature Rerating
Temperature Rerating Curve
-40 -30 -20 -10 0 10 20 30 40 50 60 70 80
10%
30%
50%
70%
90%
110%
130%
150%
170%
Temperature (°C)
Percentage of Rated Current
Average Time Current Curves
The average time current curves and Temperature Rerating curve performance is affected
by a number or variables, and these curves provided as guidance only. Customer must
verify the performance in their application.
Time in Seconds
Current in Amperes
0.01
0.1
1
10
1 10 100 1000
1.20 A
1.75 A
2.00 A
3.50 A
4.20 A
ST
123
Revised: June 4, 2010
POLYFUSE® Resettable PTCs
© 2010 Littelfuse, Inc
POLYFUSE® Resettable PTCs
ST Series
Specifications are subject to change without notice.
Please refer to www.littelfuse.com/series/ST.html for current information.
ST Series
Axial Lead Battery Strap Type > ST Series
Environmental Specifications
Operating/Storage
Temperature -40°C to +85°C
Maximum Device Surface
Temperature in Tripped State 125°C
Passive Aging +70°C, 1000 hours
-/+5% typical resistance change
Humidity Aging +85°C, 85% R.H., 7 days,
-/+5% typical resistance change
Vibration MIL–STD–883C, Condition A,
No change
Physical Specifications
Lead Material 0.13mm nominal thickness,
quarter-hard Nickel
Insulating Material Polyester tape
Part Marking System
Dimensions
E
B
D1 D2
C
A
SLIT
E
B
D1 D2
C
A
NOMINAL
0.5 x 4.0
(.02”x .15”)
Figure 1 Figure 2
(Items with S at end of part number)
Part
Number Fig.
ABCD1D2E
Inches mm Inches mm Inches mm Inches mm Inches mm Inches mm
Min. Max. Min. Max. Min. Max. Min. Max. Min. Max. Min. Max. Min. Min. Min. Min. Min Max. Min. Max.
15ST120 1 0.78 0.87 19.9 22.1 0.19 0.20 4.9 5.2 0.02 0.04 0.6 1.0 0.22 5.5 0.22 5.5 0.01 0.22 3.9 4.1
15ST120S 2 0.78 0.87 19.9 22.1 0.19 0.20 4.9 5.2 0.02 0.04 0.6 1.0 0.22 5.5 0.22 5.5 0.01 0.22 3.9 4.1
15ST175 1 0.82 0.91 20.9 23.1 0.19 0.20 4.9 5.2 0.02 0.04 0.6 1.0 0.16 4.1 0.16 4.1 0.01 0.16 3.9 4.1
15ST175S 2 0.82 0.91 20.9 23.1 0.19 0.20 4.9 5.2 0.02 0.04 0.6 1.0 0.16 4.1 0.16 4.1 0.01 0.16 3.8 4.2
30ST200 1 0.84 0.92 21.3 23.4 0.40 0.43 10.2 11.0 0.02 0.04 0.5 1.1 0.20 5.0 0.20 5.0 0.19 0.21 4.8 5.4
30ST350 1 1.12 1.25 28.4 31.8 0.51 0.53 13.0 13.5 0.02 0.04 0.5 1.1 0.25 6.3 0.25 6.3 0.24 0.26 6.0 6.6
30ST420 1 1.20 1.28 30.6 32.4 0.51 0.54 12.9 13.6 0.02 0.04 0.5 1.1 0.20 5.0 0.20 5.0 0.24 0.26 6.0 6.7
Lot Number
(Contact Littelfuse
for additional
information)
ST
120
XX9U
Product Series
Current Rating
Littelfuse
Trademark
Top Side
124
Revised: June 4, 2010
POLYFUSE® Resettable PTCs
© 2010 Littelfuse, Inc.
ST Series
Specifications are subject to change without notice.
Please refer to www.littelfuse.com/series/ST.html for current information.
Axial Lead Battery Strap Type > ST Series
QUANTITY CODE: U = 500 (bulk)
VOLTAGE RATING (VDC)
SERIES
HOLD CURRENT
(Value divided by 100 = Hold Current in Amps)
LEAD OPTIONS: Blank = standard
S = slit lead
15 ST 175 S U
Packaging
Part Ordering Number System
Part
Number
Ordering
Number
I hold
(A) I hold Code Packaging
Option Quantity Quantity &
Packaging Codes
15ST120 15ST120U 1.2 120 Bulk 500 U
15ST120S 15ST120SU 1.2 120 Bulk 500 U
15ST175 15ST175U 1.75 175 Bulk 500 U
15ST175S 15ST175SU 1.75 175 Bulk 500 U
30ST200 STD200U 2.00 200 Bulk 500 U
30ST350 STD350U 3.50 350 Bulk 500 U
30ST420 STD420U 4.20 420 Bulk 500 U
