Littelfuse 157 Series - Manual (Page 2)

© 2014 Littelfuse, Inc.
Specifications are subject to change without notice.
Revised: 02/20/14
Surface Mount Fuses
NANO 2® > 157 Fuse and Holder Combination
Average Time Current Curves
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
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 – 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
Temperature Rerating Curve
0.001
0.01
0.1
1
10
100
0.01 0.1 1 10 100 1000 10000
T
IM
E
IN
S
E
CONDS
CURRENT IN AMPS
8A 10
A
5A 6.
3A
7A 3.
5A
3.
15
A
3A 4A 2.
5A
2A 1.
5A
1.
25
A
1A 800
m
A
750
m
A
630
m
A
500
m
A
375
m
A
400
m
A
315
m
A
250
m
A
200
m
A
100
m
A
125
m
A
160
m
A
80
m
A
62
m
A
1.
6A
Note:
1. Derating depicted in this curve is in addition to the standard derating of 25% for
continuous operation.
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