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Radial lead fuses, Average time current curves – Littelfuse 279 Series User Manual

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© 2013 Littelfuse, Inc.

Specifications are subject to change without notice.

Revised: 12/19/13

Radial Lead Fuses

MICRO™ > Very Fast-Acting > 272/273/274/278/279 Series

Average Time Current Curves

100

10

1

0.1

0.01

0.001

1

10

100

0.01

0.1

0.005

1/64 A

1/100 A

1/200 A

1/32 A

1/16 A

1/8 A

1/4 A

1/2 A 3/4 A 1 A

1 1/2 A 2 A 3 A 4 A 5 A

TIME IN SECONDS

CURRENT IN AMPERES

Temperature Rerating Curve

Soldering Parameters - Wave Soldering

Dwell Time

0

20

40

60

80

100

120

140

160

180

200

220

240

260

280

300

0

10

20

30

40

50

60

70

80

90

100

110

120

130

140

150

160

170

180

190

200

210

220

230

240

Time (Seconds)

Temperature (°C) - Measured on bottom side of board

Cooling Time

Preheat Time

Wave parameter

lead-Free Recommendation

preheat:

(Depends on Flux Activation Temperature)

(Typical Industry Recommendation)

Temperature Minimum:

100

°

C

Temperature Maximum:

150

°

C

Preheat Time:

60-180 seconds

Solder pot Temperature:

260

°

C Maximum

Solder Dwell Time:

2-5 seconds

Recommended Hand-Solder Parameters:

Solder Iron Temperature: 350° C +/- 5°C
Heating Time: 5 seconds max.

Note: These devices are not recommended for IR or
Convection Reflow process.

Recommended Process Parameters: