V18AUMLA1812H Datasheet, PDF (5/7 Pages) Littelfuse – Surface Mount Multilayer Varistors (MLVs) > AUML Series

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Surface Mount Multilayer Varistors (MLVs) > AUML 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 termination option available for each solder technique is:
ReflowWave
1. Nickel Barrier (preferred)1. Nickel Barrier (preferred)
2. Silver/Platinum
The recommended solder for the AUML 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 AUML 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 50ºC before cleaning.
Lead–free (Pb-free) Soldering Recommendations
Littelfuse offers the Nickel Barrier Termination finish for the
optimum Lead–free solder performance.
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.
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.
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.
Reflow Solder Profile
230
230
230
Figure 9
FIGURE 8. REFLOW SOLDER PROFILE
Wave Solder Pr^Fo^IGf^Ui^Rle^{E 8. REFLOW SOLDER PROFILE}
300
235000
MAXIMUM WAVE 260 ^oC
MAXIMUM WAVE 260 ^oC
220500
FIGURE 8. REFLOW SOLDER PROFILE
125000
SECOND PREHEAT
110500
300
SECOND PREHEAT
15000
FIRST PREHEAT
MAXIMUM WAVE 260 ^oC
250
FIRST PREHEAT
500
2000.0 _{0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5}
0
TIME (MINUTES)
1500.0 ^{0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5}
Figure 10
FIGURE 9. WA^TV^IME^ES^(MOSIL^NEDCUEOTERNSDP⁾ PRROEFHIELAET
100
FIGURE 9. WAVE SOLDER PROFILE
FIRST PREHEAT
50
0
MAXIMUM TEMPERATURE 260˚C
0.0 0.520 - 41.00 SEC1O.5NDS2W.0ITHIN2.5˚C 3.0 3.5 4.0 4.5
MAXIMUM TEMTPIMEER(AMTIUNRUETE2S6)0˚C
20 - 40 SECONDRSAWMPITHRIANTE5˚C
FIGURE 9. WA^<V³E^˚CS^/sOLDER PRO⁶F⁰IL^-E^{150 SEC}
Lead–free Re-flow Solder^RP^AMro^{P R}fi^Al^Te^E
> 217˚C
<3˚C/s
60 - 150 SEC
> 217˚C
PREHEAT ZONE
MAXIMUM TEMPERATURE 260˚C
20P-R4E0HSEEACTOZNODNSEWITHIN 5˚C
RAMP RATE
<3˚C/s
5.600 ^{- 1506S.0EC} 7.0
> 217˚C
5.0
6.0 7.0
FIGURE 10. LEAD-FREE RE-FLOW SOLDER PROFILE
FIGURE_P1_R0_E. _HL_EE_AA_TD_Z-_OFR_NE_EE RE-FLOW SOLDER PROFILE
Figure 11
5.0
6.0 7.0
FIGURE 10. LEAD-FREE RE-FLOW SOLDER PROFILE
© 2014 Littelfuse, Inc.
Specifications are subject to change without notice.
Please refer to www.littelfuse.com/series/AUML.html for current information.
59
Revised: February 21, 2014
AUML Varistor Series