Littelfuse LT User Manual

LT Series

POLYFUSE® Resettable PTCs

Axial Lead Battery Strap Type > LT Series

Description

The new LT Series device provides reliable, noncycling protection against overcharging and short circuits events for rechargeable battery cells where resettable protection is desired.

Features

• Low resistance

• Provides overcurrent protection at 100°C trip temperature

Agency Approvals

AGENCY AGENCY FILE NUMBER

E183209

R50119583

• RoHS compliant and lead–free

• Weldable Nickel terminals

• Compact design saves board space

Applications

• Rechargeable battery cell protection

- Mobile phones

- Laptop computers

Electrical Characteristics

Part Number

hold

(A)

I (A)

trip

(Vdc)

max

(A)

max

max.

(W)

Maximum Time

Current

(A)

To Trip

Time

(Sec.)

(Ω)

min

Resistance

typ

(Ω)

1max

(Ω)

15LT070 0.7 1.5 15 100 1.0 3.50 5.00 0.100 0.200 0.340

15LT070S 0.7 1.5 15 100 1.0 3.50 5.00 0.100 0.200 0.340

24LT100 1.0 2.5 24 100 1.5 5.00 7.00 0.070 0.130 0.260

24LT100S 1.0 2.5 24 100 1.5 5.00 7.00 0.070 0.130 0.260

24LT100SS 1.0 2.5 24 100 1.5 5.00 7.00 0.070 0.130 0.260

24LT180 1.8 3.8 24 100 2.0 9.00 2.90 0.040 0.068 0.120

24LT180S 1.8 3.8 24 100 2.0 9.00 2.90 0.040 0.068 0.120

24LT180SS 1.8 3.8 24 100 2.0 9.00 2.90 0.040 0.068 0.120

24LT190 1.9 4.2 24 100 1.9 10.00 3.00 0.030 0.057 0.100

24LT190S 1.9 4.2 24 100 1.9 10.00 3.00 0.030 0.057 0.100

24LT260 2.6 5.2 24 100 2.3 13.0 5.0 0.025 0.042 0.076

24LT300 3.0 6.3 24 100 2.0 15.0 4.0 0.015 0.031 0.055

24LT310 3.1 6.0 24 100 2.5 16.0 5.0 0.018 0.030 0.055

24LT340 3.4 6.8 24 100 2.7 17.0 5.0 0.016 0.027 0.050

Items with S and SS 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.

= Hold current: maximum current device will pass without tripping in 20°C still air.

hold

= Trip current: minimum current at which the device will trip in 20°C still air.

trip

= Maximum voltage device can withstand without damage at rated current (I max)

max

= Maximum fault current device can withstand without damage at rated voltage (V

max

= Power dissipated from device when in the tripped state at 20°C still air.

= Minimum resistance of device in initial (un-soldered) state.

min

)

max

= Typical resistance of device in initial (un-soldered) state.

typ

= Maximum resistance of device at 20°C measured one hour after tripping or reﬂow

1max

soldering of 260°C for 20 sec.

Caution: Operation beyond the speciﬁed rating may result in damage and possible arcing and ﬂame.

Agency

Approvals

LT Series

Speciﬁcations are subject to change without notice. Please refer to www.littelfuse.com/series/LT.html for current information.

117

Revised: June 4, 2010

LT Series

POLYFUSE® Resettable PTCs

Axial Lead Battery Strap Type > LT Series

Temperature Rerating

Ambient Operation Temperature

-40°C -20°C 0°C 20°C 40°C 50°C 60°C 70°C 85°C

Part Number Hold Current (A)

15LT070 1.20 1.09 0.85 0.70 0.50 0.45 0.35 0.28 0.16

15LT070S 1.20 1.09 0.85 0.70 0.50 0.45 0.35 0.28 0.16

24LT100 1.86 1.60 1.40 1.00 0.80 0.70 0.60 0.44 0.23

24LT100S 1.86 1.60 1.40 1.00 0.83 0.70 0.60 0.44 0.23

24LT100SS 1.86 1.60 1.40 1.00 0.83 0.70 0.60 0.44 0.23

24LT180 3.13 2.68 2.20 1.80 1.33 1.10 0.90 0.65 0.36

24LT180S 3.13 2.68 2.20 1.80 1.33 1.10 0.90 0.65 0.36

24LT180SS 3.13 2.68 2.20 1.80 1.33 1.10 0.90 0.65 0.36

24LT190 3.32 2.86 2.40 1.90 1.48 1.25 1.10 0.79 0.43

24LT260 4.30 3.72 3.10 2.60 1.98 1.69 1.40 1.11 0.60

24LT300 5.10 4.40 3.70 3.00 2.30 1.95 1.60 1.25 0.69

24LT310 5.36 4.58 3.70 3.10 2.36 2.01 1.70 1.30 0.71

24LT340 5.52 4.79 4.00 3.40 2.60 2.24 1.90 1.51 0.78

Average Time Current Curves

1.80 A

0.70 A

1.00 A

1.90 A

2.60 A

3.00 A

3.10 A

3.40 A

Time in Seconds

0.1

0.01

1 10 100 1000

Current in Amperes

Temperature Rerating Curve

190%

170%

150%

130%

110 %

90%

70%

50%

Percentage of Rated Current

30%

10%

-40 -30 -20 -10 0 10 20 30 40 506070 80

Temperature (°C)

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.

LT Series

Revised: June 4, 2010

118

Please refer to www.littelfuse.com/series/LT.html for current information.

Speciﬁcations are subject to change without notice.

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