Littelfuse 449 Series - Manual (Page 2)

© 2014 Littelfuse, Inc.
Specifications are subject to change without notice.
Revised: 01/23/14
Surface Mount Fuses
NANO 2® > Slo-Blo ® > 449 Series
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 – 120 secs
Average ramp up rate (liquidus Temp
(T
l
) to peak
3°C/second max.
T
S(max)
to T
l
- ramp-up rate 3°C/second max.
reflow
- Temperature (T
l
) (liquidus) 217°C
- Temperature (t
l
) 60 – 90 seconds
peak Temperature (T
p
) 260 +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
Average Time Current Curves Temperature Rerating Curve
TIME IN SECONDS
CURRENT IN AMPERES
0.01
0.1
1
10
100
1000
0 1 10 100
3A 4A 5A 1.
5A
1A .750
A
.500
A
.375
A
2.
5A
2A 3.
5A
Note:
1. Derating depicted in this curve is in addition to the standard derating of 25% for
continuous operation.
Wave Soldering parameters
260°C Peak
Temperature,
3 seconds max.
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