Littelfuse MLA Varistor Series Manuel d'utilisateur Page 6
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- MARQUE LIVRES
Noté. / 5. Basé sur avis des utilisateurs
© 2013 Littelfuse, Inc.
44
Revised: December 16, 2013
Varistor Products
MLA Varistor Series
Surface Mount Multilayer Varistors (MLVs) > MLA 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
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
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 being 2 degrees per second. During the soldering
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
to less than 50º C before cleaning.
Lead–free (Pb-free) Soldering Recommendations
Littelfuse offers the Nickel Barrier Termination option (see
optimum Lead–free solder performance, consisting of a
Matte Tin outer surface plated on Nickel underlayer, plated
on Silver base metal.
flux, but there is a wide selection of pastes and fluxes
available with which the Nickel Barrier parts should be
compatible.
The reflow profile must be constrained by the maximums
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.
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 14
Figure 15
Figure 16
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