
© 2014 Littelfuse, Inc.
52
Revised: January 16, 2014
Varistor Products
MLA Automotive Varistor Series
Surface Mount Multilayer Varistors (MLVs) > MLA Automotive Series
Specifications are subject to change without notice.
Please refer to www.littelfuse.com/series/ML.html or MLA.html for current information.
Lead (Pb) Soldering Recommendations
and Wave soldering. Typical profiles are shown on the right.
The recommended solder for the MLA Automotive Series
Wave soldering is the most strenuous of the processes.
To avoid the possibility of generating stresses due to
thermal shock, a preheat stage in the soldering process
is recommended, and the peak temperature of the solder
process should be rigidly controlled.
When using a reflow process, care should be taken
to ensure that the MLA Automotive Series chip is not
subjected to a thermal gradient steeper than 4 degrees
During the soldering process, preheating to within 100
degrees of the solder's peak temperature is essential to
minimize thermal shock.
still necessary to ensure that any further thermal shocks
printed circuit boards being removed from the solder
process and subjected to cleaning solvents at room
temperature. The boards must be allowed to cool gradually
Lead–free (Pb-free) Soldering Recommendations
optimum Lead–free solder performance, consisting of a
on Silver base metal.
compatible.
evaluation purposes by Littelfuse, based upon industry
standards and practices. There are multiple choices of all
optimum combination for their process as processes vary
considerably from site to site.
FIGURE 14. REFLOW SOLDER PROFILE
FIGURE 15.WAVE SOLDER PROFILE
FIGURE 16. LEAD-FREE RE-FLOW SOLDER PROFILE
TIME (MINUTES)
300
250
200
150
100
50
0
0.0 0.5 1. 01.5 2.0 2.5 3.0 3.5 4.0 4.5
MAXIMUM WAVE 260°C
SECOND PREHEAT
FIRST PREHEAT
MAXIMUM TEMPERATURE 260˚C,
TIME WITHIN 5˚C OF PEAK
20 SECONDS MAXIMUM
PREHEAT ZONE
RAMP RATE
<3˚C/s
60 - 150 SEC
> 217˚C
PREHEAT ZONE
PREHEAT DWELL
RAMP RATE
<2°C/s
MAXIMUM TEMPERATURE
230°C
TEMPERATURE °C
TIME (MINUTES)
250
200
150
100
50
0
0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
40-80
SECONDS
ABOVE 183°C
TEMPERATURE °C
TEMPERATURE °C
TIME (MINUTES)
300
250
200
150
100
50
0
0 1.0 2.0 3.0 4.0 5.0 6.0 7. 0
FIGURE 14. REFLOW SOLDER PROFILE
FIGURE 15.WAVE SOLDER PROFILE
FIGURE 16. LEAD-FREE RE-FLOW SOLDER PROFILE
TIME (MINUTES)
300
250
200
150
100
50
0
0.0 0.5 1. 01.5 2.0 2.5 3.0 3.5 4.0 4.5
MAXIMUM WAVE 260°C
SECOND PREHEAT
FIRST PREHEAT
MAXIMUM TEMPERATURE 260˚C,
TIME WITHIN 5˚C OF PEAK
20 SECONDS MAXIMUM
PREHEAT ZONE
RAMP RATE
<3˚C/s
60 - 150 SEC
> 217˚C
PREHEAT ZONE
PREHEAT DWELL
RAMP RATE
<2°C/s
MAXIMUM TEMPERATURE
230°C
TEMPERATURE °C
TIME (MINUTES)
250
200
150
100
50
0
0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
40-80
SECONDS
ABOVE 183°C
TEMPERATURE °C
TEMPERATURE °C
TIME (MINUTES)
300
250
200
150
100
50
0
0 1.0 2.0 3.0 4.0 5.0 6.0 7. 0
FIGURE 14. REFLOW SOLDER PROFILE
FIGURE 15.WAVE SOLDER PROFILE
FIGURE 16. LEAD-FREE RE-FLOW SOLDER PROFILE
TIME (MINUTES)
300
250
200
150
100
50
0
0.0 0.5 1. 01.5 2.0 2.5 3.0 3.5 4.0 4.5
MAXIMUM WAVE 260°C
SECOND PREHEAT
FIRST PREHEAT
MAXIMUM TEMPERATURE 260˚C,
TIME WITHIN 5˚C OF PEAK
20 SECONDS MAXIMUM
PREHEAT ZONE
RAMP RATE
<3˚C/s
60 - 150 SEC
> 217˚C
PREHEAT ZONE
PREHEAT DWELL
RAMP RATE
<2°C/s
MAXIMUM TEMPERATURE
230°C
TEMPERATURE °C
TIME (MINUTES)
250
200
150
100
50
0
0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
40-80
SECONDS
ABOVE 183°C
TEMPERATURE °C
TEMPERATURE °C
TIME (MINUTES)
300
250
200
150
100
50
0
0 1.0 2.0 3.0 4.0 5.0 6.0 7. 0
Reflow Solder Profile
Wave Solder Profile
Lead–free Re-flow Solder Profile
Figure 12
Figure 13
Figure 14
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