Littelfuse 429 Series - Manual (Page 2)

© 2013 Littelfuse, Inc.
Specifications are subject to change without notice.
Revised: 12/19/13
Surface Mount Fuses
Thin Film > 1206 Size > Very Fast-Acting > 429 Series
Average Time Current Curves
7A
TIME IN SECONDS
CURRENT IN AMPERES
0.01
0.1
0.1
1
1
10
100
10 100
0.001
Reflow Condition Pb – Free assembly
pre Heat
- Temperature min (T
s(min)
) 150°C
- Temperature max (T
s(max)
) 200°C
- Time (min to max) (t
s
) 60 – 180 secs
Average ramp up rate (liquidus Temp
(T
l
) to peak
5°C/second max
T
S(max)
to T
l
- Ramp-up Rate 5°C/second max
Reflow
- Temperature (T
l
) (liquidus) 217°C
- Temperature (t
l
) 60 – 150 seconds
peak Temperature (T
p
) 250 +0/-5 °C
Time within 5°C of actual peak
Temperature (t
p
)
20 – 40 seconds
Ramp-down Rate 5°C/second max
Time 25°C to peak Temperature (T
p
) 8 minutes Max.
Do not exceed 260°C
Soldering Parameters
Temperature Rerating Curve
Wave Soldering 260°C, 10 seconds max.
Note:
1. Derating depicted in this curve is in addition to the standard derating of 25% for
continuous operation.
Example:
For continuous operation at 70 degrees celsius, the fuse should be deratedas follows:
I = (0.75)(0.80)I
RAT
= (0.60)I
RAT
2. The temperature derating curve represents the nominal conditions. For questions
about temperature derating curve, please consult Littelfuse technical support
for assistance.
Time
Te
mperatur
e
T
P
T
L
T
S(max)
T
S(min)
25
t
P
t
L
t
S
time to peak temperature
(t 25ºC to peak)
Ramp-down
Ramp-up
Preheat
Critical Zone
T
L
to T
P