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© 2017 Littelfuse, Inc.
Specifications are subject to change without notice.
Revised: 03/03/17
Axial Lead & Cartridge Fuses
PICO
®
ll > Very Fast-Acting Fuse > 251/253 Series
Average Time Current Curves
Soldering Parameters
100
10
1
0.1
0.01
0.001
.062A
0.05 0.1 110100 1000
.125A .250A .375A .500A .750A .630A 1A 1.5A 2A 2.5A 3A 3.5A 4A 5A 7A 10A 12A 15A
TIME IN SECONDS
CURRENT IN AMPERES
1.25A
Recommended Hand Soldering 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:
Note:
1. Re-rating depicted in this curve is in addition to the standard derating of 25% for
continuous operation.
Temperature Re-rating Curve
Wave Parameter
Lead-Free Recommendation
for 251 Series only
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