V18MLA1206H 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
225500
MAXIMUM TEMPERATURE
MAXIMUM _{2T3E0M°CPERATURE}
2200500
230°C
MAXIMUM2T3E0M°CPERA_AT_BSSU_EOER_44CCVE_{00OEO--88NN1008DD3SS°C}
21150500
1100500
ABOVE 183°C
R<R<22AA°°MMCCP/P/ss
RRAASTTEEE4C0O-8N0DS
ABOVE 183°C
PREHEAT
PREHEAT
DDWWEELLR<LL2A°MCP/s
RATE
150500
PREHEAT ZONE
PREHPERAETHEZOATNEDWELL
500 ₀₀
PREHEAT ZONE
00..55 11..00 11..55 22..00 22..55 33..00 33..55 44..00
Figure 14
0
TIME (MINUTES)
TIME (MINUTES)
Wave So⁰lde^FFr^0IIGGP^.5UUro^RREEfi¹l^11.e^{044.. RREE1FF.T5LLIMOOEWW(MSS2I.OON0LULDDTEEES2RR).5PPRROOFF3.II0LLEE 3.5}
4.0
FIGURE 14. REFLOW SOLDER PROFILE
300
300
MAXIMUM WAVE 260°C
22355000
MAXIMUM WAVE 260°C
2200500
MAXIMUM WAVE 260°C
112550000
SECOND PREHEAT
SECOND PREHEAT
1100500
FIRST PREHEASTECOND ^PREHEAT
150500
FIRST PREHEAT
Lead–free (Pb-free) Soldering Recommendations
5000.0 _0.5
FIRST PREHEAT
1.0 1.5 2.0 2.5
3.0
3.5
4.0
4.5
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5
Figure 15
TIME (MINUTES)
TIME (MINUTES)
0
0.0 0_FF.5_IIGGUURR1.0_{EE 1155..}1._WW5 _AATIVVMEE2E._SS0(M_{OOILNLDDU2.TEE}5E_{RRSPP) RR}3._OO0 _FFIILLE3_E.5 4.0 4.5
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.
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.
FIGURE 15. WAVE SOLDER PROFILE
Lead–free Re-flow Solder Profile
330000
MAXIMUM TEMPERATURE 260˚C,
MTIAMXEIMWUITMHTINEM5˚PCEORFATPUERAEK 260˚C,
23250500
T20IMSEEWCOITNHDINS5M˚CAXOIFMUPEMAK
20 SECONDS MAXIMUM
MAXIMUM TEMPERRAAMTUPRREA2T6E0˚C,
2200500
TIME WITHIN 5˚C OR<3AF˚MCP/PEsARKATE
20 SECONDS MAX<I3M˚CU/Ms
RAMP RATE
21150500
<3˚C/s
1100500
PPRREEHHEEAATT ZZOONNEE
6600 _>>-- 112255110077˚˚SSCCEECC
60 - 150 SEC
> 217˚C
150500
PREHEAT ZONE
500 ₀₀
11..00
22..00
33..00 44..00
55..00
66..00
77..00
TIME (MINUTES)
0
TIME (MINUTES)
Figure
16^{0 FFIIGGUURR1.EE0 1166..}
LL²EE^.AA⁰ DD--FFRR³EE^.EE⁰ RREE--FF⁴LL^.0OOWW SSOO^5.LL⁰DDEERR PP^6.RR⁰OOFFIILLEE^7.0
TIME (MINUTES)
FIGURE 16. LEAD-FREE RE-FLOW SOLDER PROFILE
MLA Varistor Series
44
Revised: December 16, 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.