V181206XMLAXX Datasheet, PDF (6/8 Pages) Littelfuse – RoHS compliant Rated for surge current (8 x 20 us)

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
B

4O1C"H

4O1C
PS

4O1C 

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.
0ODF
UIF
TPMEFSJOH
QSPDFTT
IBT
CFFO
DPNQMFUFE
JU
JT

still necessary to ensure that any further thermal shocks
BSF
BWPJEFE
0OF
QPTTJCMF
DBVTF
PG
UIFSNBM
TIPDL
JT
IPU

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
/
TVGmY
JO
1BSU
/VNCFSJOH
4ZTUFN
GPS
PSEFSJOH
GPS
UIF

optimum Lead–free solder performance, consisting of a
Matte Tin outer surface plated on Nickel underlayer, plated
on Silver base metal.
5IF
QSFGFSSFE
TPMEFS
JT

4O"H$V
XJUI
BO
3."

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
JO
UIF
-FBEoGSFF
3FnPX
1SPmMF
'PS
-FBEoGSFF
XBWF

TPMEFSJOH
UIF
8BWF
4PMEFS
1SPmMF
TUJMM
BQQMJFT
/PUF
UIF
-FBEoGSFF
QBTUF
nVY
BOE
QSPmMF
XFSF
VTFE
GPS

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
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 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
100
PREHEAT ZONE
50
0
0
1.0
2.0 3.0 4.0 5.0 6.0 7.0
Figure 16
TIME (MINUTES)
MLA Varistor Series
Revision: November 30, 2011
©2011 Littelfuse, Inc.
Specifications are subject to change without notice.
Please refer to www.littelfuse.com/series/ML.html or MLA.html for current information.