V18MLE1206NH View Datasheet(PDF) - Littelfuse, Inc
Part Name
Description
Manufacturer
V18MLE1206NH Datasheet PDF : 7 Pages
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Surface Mount Varistors
Multilayer Transient Voltage Suppressor
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MLE Varistor Series
Soldering Recommendations
The principal techniques used for the soldering of components in surface
mount technology are Infrared (IR) re-flow, vapour phase re-flow, and
wave soldering. When wave soldering, the MLE suppressor is attached
to the circuit board by means of an adhesive. The assembly is then
placed on a conveyor and run through the soldering process to contact
the wave. With IR and vapour phase re-flow, the device is placed in a
solder paste on the substrate. As the solder paste is heated, it reflows
and solders the unit to the board.
The recommended solder for the MLE 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. For 0402 size devices,
IR re-flow is recommended.
When using a reflow process, care should be taken to ensure that the
MLE 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. Examples of the
soldering conditions for the MLE series of suppressors are given in the
tables below.
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.
Termination Options
Littelfuse offers two types of electrode termination finish for the
MLE series:
1. Silver/Platinum (standard) (Not 0402 and 0603 sizes)
2. Silver/Palladium (optional)
3. Nickel Barrier (optional for 0402-1210 package size)
(The ordering information section describes how to designate them.)
250
MAXIMUM
TEMPERATURE 222oC
200
40-80
SECONDS
ABOVE 183 oC
150
RAMP RATE
<2oC /s
100
PREHEAT DWELL
50
PREHEAT ZONE
0
0
0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0
TIME (MINUTES)
FIGURE 5. REFLOW SOLDER PROFILE
300
MAXIMUM WAVE 260 oC
250
200
150
SECOND PREHEAT
100
FIRST PREHEAT
50
0
0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5
TIME (MINUTES)
FIGURE 6. WAVE SOLDER PROFILE
250
MAXIMUM
TEMPERATURE 222oC
200
40-80
SECONDS
ABOVE 183 oC
150
RAMP RATE
>50oC /s
100
PREHEAT ZONE
50
0
0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
TIME (MINUTES)
FIGURE 7. VAPOR PHASE SOLDER PROFILE
136
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