V14MLA0603NR Datasheet, PDF (6/8 Pages) Littelfuse – Varistor Products Surface Mount Multilayer Varistors (MLVs) > MLA Series

Varistor Products
Surface Mount Multilayer Varistors (MLVs) > MLA Series
Lead (Pb) Soldering Recommendations
The principal techniques used for the soldering of
components in surface mount technology are IR Re-flow
and Wave soldering. Typical profiles are shown on the right.
The recommended solder for the MLA suppressor is
a 62/36/2 (Sn/Pb/Ag), 60/40 (Sn/Pb) or 63/37 (Sn/Pb).
Littelfuse also recommends an RMA solder flux.
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 chip is not subjected to a thermal
gradient steeper than 4 degrees per second; the ideal
gradient being 2 degrees per second. During the soldering
process, preheating to within 100 degrees of the solder's
peak temperature is essential to minimize thermal shock.
Once the soldering process has been completed, it is
still necessary to ensure that any further thermal shocks
are avoided. One possible cause of thermal shock is hot
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
to less than 50º C before cleaning.
Reflow Solder Profile
250
MAXIMUM TEMPERATURE
230°C
200
40-80
SECONDS
ABOVE 183°C
150
RAMP RATE
<2°C/s
100
PREHEAT DWELL
50
PREHEAT ZONE
0
0
Figure 14
0.5 1.0
1.5 2.0 2.5 3.0 3.5 4.0
TIME (MINUTES)
Wave Solder Profile
300
MAXIMUM WAVE 260°C
250
200
150
SECOND PREHEAT
100
FIRST PREHEAT
50
0
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5
Figure 15
TIME (MINUTES)
Lead–free (Pb-free) Soldering Recommendations
Littelfuse offers the Nickel Barrier Termination option (see
"N" suffix in Part Numbering System for ordering) for the
optimum Lead–free solder performance, consisting of a
Matte Tin outer surface plated on Nickel underlayer, plated
on Silver base metal.
The preferred solder is 96.5/3.0/0.5 (SnAgCu) with an RMA
flux, but there is a wide selection of pastes and fluxes
available with which the Nickel Barrier parts should be
compatible.
Lead–free Re-flow Solder Profile
300
MAXIMUM TEMPERATURE 260˚C,
TIME WITHIN 5˚C OF PEAK
250
20 SECONDS MAXIMUM
RAMP RATE
200
<3˚C/s
60 - 150 SEC
> 217˚C
150
The reflow profile must be constrained by the maximums
in the Lead–free Reflow Profile. For Lead–free wave
soldering, the Wave Solder Profile still applies.
100
PREHEAT ZONE
50
Note: the Lead–free paste, flux and profile were used for
evaluation purposes by Littelfuse, based upon industry
standards and practices. There are multiple choices of all
three available, it is advised that the customer explores the
optimum combination for their process as processes vary
considerably from site to site.
0
0
1.0
2.0 3.0 4.0 5.0 6.0 7.0
Figure 16
TIME (MINUTES)
MLA Varistor Series
44
Revised: May 8, 2013
© 2013 Littelfuse, Inc.
Specifications are subject to change without notice.
Please refer to www.littelfuse.com/series/ML.html or MLA.html for current information.