Transientology
Thin Film > 0402 Size > Very Fast-Acting > 435 Series
Surface Mount Fuses
Introduction to Circuit Protection
Temperature Rerating Curve
Average Time Current Curves
1A
1.25A
1.5A
1.75A
2A
2.5A
.375A
.25A
.75A
.5A
3A
3.5A
4A
5A
100
10
TIME IN SECONDS
1
0.1
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.
0.001
0.1
1.0
10.0
100.0
CURRENT IN AMPERES
0.01
Soldering Parameters
reflow condition
- Temperature min (T
s(min)
)
pre Heat
- Temperature max (T
s(max)
)
- Time (min to max) (t
s
)
Average ramp up rate (liquidus Temp
(T
l
) to peak
T
S(max)
to T
l
- ramp-up rate
reflow
- Temperature (T
l
) (liquidus)
- Temperature (t
l
)
Pb – Free assembly
150°C
60 – 120 secs
5°C/second max
5°C/second max
217°C
60 – 150 seconds
250
+0/-5
T
P
T
L
Temperature
t
P
Ramp-up
Critical Zone
T
L
to T
P
200°C
T
S(max)
T
S(min)
Preheat
t
L
Ramp-down
t
S
time to peak temperature
(t 25ºC to peak)
25
Time
peak Temperature (T
p
)
Time within 5°c of actual peak
Temperature (t
p
)
ramp-down rate
Time 25°c to peak Temperature (T
p
)
Do not exceed
°C
20 – 40 seconds
5°C/second max
8 minutes Max.
260°C
Wave Soldering
260°C, 10 seconds max.
435 Series
46
© 2009 Littelfuse, Inc.
Specifications are subject to change without notice.
Please refer to www.littelfuse.com/series/435.html for current information.
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