Surface Mount Fuses
Introduction to Circuit Protection
Transientology
Ceramic Fuse > 469 Series
Temperature Rerating Curve
Average Time Current Curves
100
4A
5A
6A
7A
8A
140
PERCENT OF RATING
120
10
100
TIME IN SECONDS
80
1
60
40
-65
-45
-25
-5
15
35
55
75
95
115
135
155
TEMPERATURE (°C)
0.1
1. Rerating depicted in this curve is in addition to the standard rerating of 20% for
continuous operation.
0.01
I = (0.80)(0.85)I
RAT
= (0.68)I
RAT
0.001
1
10
100
1000
CURRENT IN AMPERES
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
)
150°C
60 – 180 seconds
3°C/second max.
5°C/second max.
217°C
60 – 150 seconds
260
+0/-5
T
P
Ramp-up
t
P
Critical Zone
T
L
to T
P
Temperature
200°C
T
L
T
S(max)
Preheat
t
L
Ramp-down
T
S(min)
t
S
25
time to peak temperature
(t 25ºC to peak)
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
10 – 30 seconds
6°C/second max.
8 minutes max.
260°C
Wave Soldering
260°C, 10 seconds max.
469 Series
© 2009 Littelfuse, Inc.
Specifications are subject to change without notice.
Please refer to www.littelfuse.com/series/469.html for current information.
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