Revised: January 7, 2009

Introduction to Circuit Protection

Introduction to Circuit Protection

Transientology

132

© 2009 Littelfuse, Inc.

Specifications are subject to change without notice.

Radial Lead Fuses

272/273/274/278/279 Series

Please refer to www.littelfuse.com/series/272.html, /273.html, /274.html,

/278.html or /279.html for current information.

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

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

Time (Seconds)

Cooling Time

Preheat Time

Wave Parameter

Lead-Free Recommendation

Preheat:

(Depends on Flux Activation Temperature)

(Typical Industry Recommendation)

Temperature Minimum:

100

Temperature Maximum:

150

Preheat Time:

60-180 seconds

Solder PotTemperature:

260

Solder DwellTime:

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: