PRODUCTION GUIDELINES
AUTOMATED ASSEMBLY
The LC modules are packaged in a hybrid SMD package that supports hand- or
automated-assembly techniques. Since LC devices contain discrete
components internally, the assembly procedures are critical to ensuring the
reliable function of the LC product. The following procedures should be reviewed
with and practiced by all assembly personnel.
For high-volume assembly most users will want to auto-place the modules. The
receivers have been designed to maintain compatibility with reflow processing
techniques; however, due to the module's hybrid nature certain aspects of the
assembly process are far more critical than for other component types.
Following are brief discussions of the three primary areas where caution must be
observed.
PAD LAYOUT
The following pad layout diagrams are designed to facilitate both hand and
automated assembly.
Reflow Temperature Profile
The single most critical stage in the automated assembly process is the reflow
process. The reflow profile below should be closely followed since excessive
temperatures or transport times during reflow will irreparably damage the modules.
Assembly personnel will need to pay careful attention to the oven's profile to
ensure that it meets the requirements necessary to successfully reflow all
components while still meeting the limits mandated by the modules themselves.
LC-S RX Layout Rev. 1
TX Layout Pattern Rev. 2
LC-P RX Layout Pattern Rev. 3
(Not to Scale)
Compact SMD Version
Pinned SMD Version
(Not to Scale)
(Not to Scale)
0.100"
0.150
.100
0.065"
0.610"
0.310"
0.100"
.070
0.070"
0.775
0.070"
0.100"
300
250
200
150
100
50
Ideal Curve
Limit Curve
Forced Air Reflow Profile
Figure 10: Recommended Pad Layout
220oC
210oC
RECEIVER HAND ASSEMBLY
180oC
The LC-S Receiver’s primary mounting
surface is sixteen pads located on the
bottom of the module. Since these pads
are inaccessible during mounting,
castellations that run up the side of the
module have been provided to facilitate
solder wicking to the module's under-
side. If the recommended pad place-
ment has been followed, the pad on the
board will extend slightly past the edge
of the module. Touch both the PCB pad
and the module castellation with a fine
soldering tip. Tack one module corner
first, then work around the remaining
attachment points using care not to
exceed the times listed below.
Reflow Zone
125oC
Soldering Iron
Tip
20-40 Sec.
Soak Zone
2 Minutes Max.
Preheat Zone
2-2.3 Minutes
Cooling
Ramp-up
1-1.5 Minutes
0
0
30
60
90
120 150 180 210 240 270 300 330 360
Time (Seconds)
Solder
PCB Pads
Castellations
Figure 12: Required Reflow Profile
Shock During Reflow Transport
Revision 2 - 11/98
Figure 11: LC-S Soldering Technique
Since some internal module components may reflow along with the components
placed on the board being assembled, it is imperative that the module not be
subjected to shock or vibration during the time solder is liquidus.
Washability
Absolute Maximum Solder Times
The modules are wash resistant, but are not hermetically sealed. They may be
subject to a standard wash cycle; however, a twenty-four-hour drying time
should be allowed before applying electrical power to the modules. This will allow
any moisture that has migrated into the module to evaporate, thus eliminating the
potential for shorting during power-up or testing.
Hand-Solder Temp. TX +225°C for 10 Sec.
Hand-Solder Temp. RX +225°C for 10 Sec.
Recommended Solder Melting Point +180°C
Reflow Oven: +220° Max. (See adjoining diagram)
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