Littelfuse 72R User Manual

72R Series

POLYFUSE® Resettable PTCs

Radial Leaded > 72R Series

Description

The 72R Series is designed to provide overcurrent
protection to 72Vdc maximum voltage with a maximum
40A short circuit rating.

Features

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40A short circuit rating

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and Halogen Free*

Agency Approvals

AGENCY AGENCY FILE NUMBER

E183209

R50119318

Applications

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range of low voltage power
supplies

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Electrical Characteristics

Maximum Time

To Trip

Current

(A)

Time

(Sec.)

Part Number

I

hold

(A)

I
(A)

trip

V

max

(Vdc)

I

(A)

max

Pd

typ.
(W)

72R020X 0.20 0.40 72 40 0.41 1.00 2.20 1.830 4.400

72R025X 0.25 0.50 72 40 0.45 1.25 2.50 1.250 3.000

72R030X 0.30 0.60 72 40 0.49 1.50 3.00 0.880 2.100

72R040X 0.40 0.80 72 40 0.56 2.00 3.80 0.550 1.290

72R050X 0.50 1.00 72 40 0.77 2.50 4.00 0.500 1.170

72R065X 0.65 1.30 72 40 0.88 3.25 5.30 0.310 0.720

72R075X 0.75 1.50 72 40 0.92 3.75 6.30 0.250 0.600

72R090X 0.90 1.80 72 40 0.99 4.50 7.20 0.200 0.470

72R110X 1.10 2.20 72 40 1.50 5.50 8.20 0.150 0.380

72R135X 1.35 2.70 72 40 1.70 6.75 9.60 0.120 0.300

72R160X 1.60 3.20 72 40 1.90 8.00 11.40 0.090 0.220

72R185X 1.85 3.70 72 40 2.10 9.25 12.60 0.080 0.190

72R250X 2.50 5.00 72 40 2.50 12.50 15.60 0.050 0.130

72R300X 3.00 6.00 72 40 2.80 15.00 19.80 0.040 0.100

72R375X 3.75 7.50 72 40 3.20 18.75 24.00 0.030 0.080

Resistance

R

min

(Ω)

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general electronics using a
low voltage power supply

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Agency

Approvals

R

1max

(Ω)

XX

XX

XX

XX

XX

XX

XX

XX

XX

XX

XX

XX

XX

XX

XX

72R Series

I

= Hold current: maximum current device will pass without tripping in 23°C still air.

hold

= Trip current: minimum current at which the device will trip in 23°C still air.

I

trip

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

V

max

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

I

max

= Power dissipated from device when in the tripped state at 23°C still air.

P

d

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

R

min

* Effective January 1, 2010, all 72R PTC products will be manufactured Halogen Free (HF). Existing Non-Halogen Free 72R PTC products may continue to be sold, until supplies are depleted.

© 2010 Littelfuse, Inc

Specifications are subject to change without notice.
Please refer to www.littelfuse.com/series/72R.html for current information.

)

max

Revised: July 12, 2010

= Maximum resistance of device at 23°C measured one hour after tripping or reflow

R

1max

soldering of 260°C for 20 sec.

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

91

72R Series

POLYFUSE® Resettable PTCs

Radial Leaded > 72R Series

Temperature Rerating

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)

72R020X 0.31 0.27 0.24 0.20 0.16 0.14 0.13 0.11 0.08

72R025X 0.39 0.34 0.30 0.25 0.20 0.18 0.16 0.14 0.10

72R030X 0.47 0.41 0.36 0.30 0.24 0.22 0.19 0.16 0.12

72R040X 0.62 0.54 0.48 0.40 0.32 0.29 0.25 0.22 0.16

72R050X 0.78 0.68 0.60 0.50 0.41 0.36 0.32 0.27 0.20

72R065X 1.01 0.88 0.77 0.65 0.53 0.47 0.41 0.35 0.26

72R075X 1.16 1.02 0.89 0.75 0.61 0.54 0.47 0.41 0.30

72R090X 1.40 1.22 1.07 0.90 0.73 0.65 0.57 0.49 0.36

72R110X 1.71 1.50 1.31 1.10 0.89 0.79 0.69 0.59 0.44

72R135X 2.09 1.84 1.61 1.35 1.09 0.97 0.85 0.73 0.54

72R160X 2.48 2.18 1.90 1.60 1.30 1.15 1.01 0.86 0.64

72R185X 2.87 2.52 2.20 1.85 1.50 1.33 1.17 1.00 0.74

72R250X 3.88 3.40 2.98 2.50 2.03 1.80 1.58 1.35 1.00

72R300X 4.65 4.08 3.57 3.00 2.43 2.16 1.89 1.62 1.20

72R375X 5.81 5.10 4.46 3.75 3.04 2.70 2.36 2.03 1.50

Average Time Current Curves

0.20A

0.25A

0.30A

0.40A

0.50A

0.65A

0.75A

0.90A

1.10A

100

10

1

Time in Seconds

0.1

0.01

0.1 1 10 100

Current in Amperes

1.35A

1.60A

1.85A

2.50A

3.00A

3.75A

72R

Temperature Rerating Curve

170%

150%

130%

110%

90%

70%

50%

Percentage of Rated Current

30%

10%

-40 -30 -20 -10 0 10 20 30 40 50 60 70 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.

72R Series

Revised: July 12, 2010

92

Please refer to www.littelfuse.com/series/72R.html for current information.

Specifications are subject to change without notice.

© 2010 Littelfuse, Inc.

Soldering Parameters - Wave Soldering

Refer to the condition recommended by

Pre-Heating Zone

the flux manufacturer.

Max. ramping rate should not exceed
4°C/Sec.

POLYFUSE® Resettable PTCs

Radial Leaded > 72R Series

260

220

Soldering Cooling

Soldering Zone

Max. solder temperature should not
exceed 260°C

Cooling Zone Cooling by natural convection in air.

Physical Specifications

Lead Material

Soldering
Characteristics

Insulating Material

Lead Solderability

0.20-0.40A: Tin-plated Copper clad steel

0.50-3.75A: Tin-plated Copper

Solderability per MIL–STD–202, Method
208E

Cured, flame retardant epoxy polymer
meets UL 94V-0 requirements.

Marked with ‘LF’, voltage, current rating,
and date code.

190

160

Temperature (°C)

0

Preheating

60 min.

5 max.

Time(s)

Environmental Specifications

Operating/Storage
Temperature

Maximum Device Surface
Temperature in Tripped State

Passive Aging

Humidity Aging

Thermal Shock

-40°C to +85°C

125°C

+85°C, 1000 hours

-/+5% typical resistance change

+85°C, 85% R.H. 1000 hours

-/+5% typical resistance change

+85°C to -40°C 10 times

-/+5% typical resistance change

72R Series

© 2010 Littelfuse, Inc

Specifications are subject to change without notice.
Please refer to www.littelfuse.com/series/72R.html for current information.

Solvent Resistance MIL–STD–202, Method 215F

Moistrue Sesitivity Level Level 1, J–STD–020C

93

Revised: July 12, 2010

72R Series