Varistor Products
©2010 Littelfuse, Inc.
Revision: December 16, 2010
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
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and Wave soldering. Typical profiles are shown on the right.
The recommended solder for the MLA Automotive Series
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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
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During the soldering process, preheating to within 100
degrees of the solder's peak temperature is essential to
minimize thermal shock.
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still necessary to ensure that any further thermal shocks
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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
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Lead–free (Pb-free) Soldering Recommendations
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optimum Lead–free solder performance, consisting of a
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on Silver base metal.
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compatible.
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evaluation purposes by Littelfuse, based upon industry
standards and practices. There are multiple choices of all
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optimum combination for their process as processes vary
considerably from site to site.
PREHEAT ZONE
PREHEAT DWELL
RAMP RATE
<2°C/s
MAXIMUM TEMPERATURE
230°C
TEMPERATURE °C
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
TIME (MINUTES)
300
250
200
150
100
50
0
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5
MAXIMUM WAVE 260°C
SECOND PREHEAT
FIRST PREHEAT
TEMPERATURE °C
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
TEMPERATURE °C
TIME (MINUTES)
300
250
200
150
100
50
00 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