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

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.

PREHEAT ZONE

PREHEAT DWELL

RAMP RATE

<2°C/s

MAXIMUM TEMPERATURE

230°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

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

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

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