Littelfuse 440 User Manual

Surface Mount Fuses

Ceramic Fuse > 440 Series

440 Series, 1206 High I2t Fuse

Agency Approvals

AGENCY AGENCY FILE NUMBER AMPERE RANGE

E10480 .25A - 8A

LR 29862 .25A - 8A

Description

The 440 Series is a 100% Lead-free, RoHS compliant and
Halogen-free fuse series designed specifically to provide
over-current protection to circuits that operate under high
working ambient temperatures up to 150ºC and high inrush
currents. The general design ensures excellent temperature
stability and performance reliability. This high I

2

t fuse series
is designed to have ultra high inrush current withstand
capability to avoid nuisance fuse open.

Features

• OperatingTemperature

from -55ºC to +150ºC

• 100%Lead-free,RoHS

compliant and Halogen-free

• Suitableforbothleaded

and lead-free reflow / wave
soldering

• UltrahighI

2

t values

Applications

• LCDDisplays

• Servers

• NotebookComputers

• Scanners

• DataModems

• HardDiskDrives

• Printers

Electrical Characteristics for Series

% of Ampere

Rating

100% 0.25A - 8A 4 hours, Minimum
350% 0.25A - 8A 5 secs., Maximum

Ampere Rating Opening Time at 25ºC

Additional Information

Datasheet

Resources

Samples

Electrical Specifications by Item

Ampere

Rating

0.25 .250 125

0.375 .375 125 1.216 0.01455 0.4993 0.187 x X

0.75 .750 63 50 A @ 63 V AC/DC 0.4624 0.09312 0.3983 0.299 x X

1.25 1.25 50 0.2268 0.40200 0.3240 0.405 x X

1.75 1.75 32

Notes:

1. AC Interrupting Rating tested at rated voltage with unity power factor. DC Interrupting
Rating tested at rated voltage with time constant < 0.8 msec.

2. Nominal Resistance measured with < 10% rated current.

3. Nominal Melting I²t measured at 1 msec. opening time.

4. Nominal Voltage Drop measured at rated current after temperature has stabilized.

Amp

Code

(A)

0.5 .500 63 50 A @ 63 V AC/DC 0.8140 0.02642 0.4831 0.242 x X

1 0 01. 50

1. 5 01. 5 50 0.1759 0.50652 0.3215 0.482 x X

2 002. 32 0.03802 0.4326 0.0792 0.158 x X

2.5 02.5 32 0.02850 0.8191 0.0747 0.187 x X
3 003. 32 0.02252 1.232 0.0742 0.223 x X

3.5 03.5 32 0.01845 1.789 0.0757 0.265 x X
4 004. 32 0.01553 2.601 0.0709 0.284 x X
5 005. 32 0.01164 4.761 0.0654 0.327 x X
7 0 0 7. 32 0.00753 8.464 0.0696 0.487 x X
8 008. 32 0.00634 12.95 0.0655 0.524 x X

Max.

Voltage

Rating (V)

Interrupting Rating

50 A @ 125 V AC/DC

50 A @ 50 V DC

50 A @ 50 V AC

50 A @ 32 V AC/DC

(AC/DC)

1

Nominal

Resistance

(Ohms)

2.140 0.00649 0.5260 0.132 x X

0.3096 0.21054 0.3457 0.346 x X

0.04518 0.3312 0.0777 0.136 x X

Melting I2t

2

Nominal

(A2Sec.)

Nominal Voltage

Drop At Rated

3

Current (V)

Devices designed to carry rated current for 4 hours minimum. It is recommended that
devices be operated continuously at no more than 80% rated current. See “Temperature
Derating Curve”for additional derating information.

Devices designed to be mounted with marking code facing up.

Nominal Power

Dissipation At

4

Rated Current (W)

Specifications are subject to change without notice.

Agency Approvals

© 2013 Littelfuse, Inc.

Revised: 12/19/13

Surface Mount Fuses

Ceramic Fuse > 440 Series

Temperature Derating Curve

140

120

100

80

PERCENT OF RATING

60

40

-65 -45 -25 -5 15 35 55 75 95 115 135 155

TEMPERATURE (°C)

Note:

1. Derating depicted in this curve is in addition to the standard derating of 20% for
continuous operation.

Example:
For continuous operation at 75 degrees celsius, the fuse should be derated as follows:

I = (0.80)(0.85)I

RAT

= (0.68)I

RAT

Average Time Current Curves

100

10

1

TIME IN SECONDS

0.1

0.01

Soldering Parameters

Reflow Condition Pb-free assembly

- Temperature Min (T

Pre Heat

- Temperature Max (T

- Time (Min to Max) (ts) 60 – 180 seconds

Average Ramp-Up Rate (Liquidus Temp
(T

) to peak)

L

to TL - Ramp-up Rate 5°C/second max.

T

S(max)

Reflow

- Temperature (TL) (Liquidus) 217°C

- Temperature (tL) 60 – 150 seconds

Peak Temperature (TP) 260

Time within 5°C of actual peak
Temperature (t

)

p

Ramp-down Rate 6°C/second max.

Time 25°C to peak Temperature (T
Do not exceed 260°C

) 150°C

s(min)

) 200°C

s(max)

3°C/second max.

+0/-5

°C

10 – 30 seconds

) 8 minutes max.

P

0.001

0.1 1.0 10.0 100.0 1000.

T

P

T

L

T

S(max)

T

S(min)

Temperature

25

time to peak temperature

(t 25ºC to peak)

CURRENT IN AMPERES

Ramp-up

Preheat

t

S

t

P

t

L

Time

Critical Zone

T

to T

L

P

Ramp-down

Wave Soldering 260°C, 10 seconds max.

© 2013 Littelfuse, Inc.
Specifications are subject to change without notice.
Revised: 12/19/13