6
Precautions
Lead Forming
• The leads of an LED lamp may be preformed or cut to
length prior to insertion and soldering into PC board.
• If lead forming is required before soldering, care must
be taken to avoid any excessive mechanical stress
induced to LED package. Otherwise, cut the leads
of LED to length after soldering process at room
temperature. The solder joint formed will absorb the
mechanical stress of the lead cutting from traveling to
the LED chip die attach and wirebond.
• It is recommended that tooling made to precisely form
and cut the leads to length rather than rely upon hand
operation.
Soldering Conditions
• Care must be taken during PCB assembly and soldering
process to prevent damage to LED component.
• The closest LED is allowed to solder on board is 1.59
mm below the body (encapsulant epoxy) for those
parts without stando.
• Recommended soldering conditions:
Wave
Soldering
Manual Solder
Dipping
Pre-heat Temperature
105 °C Max.
–
Pre-heat Time 60 sec Max. –
Peak Temperature
250 °C Max. 260 °C Max.
Dwell Time 3 sec Max. 5 sec Max.
• Wave soldering parameter must be set and maintained
according to recommended temperature and dwell
time in the solder wave. Customer is advised to
periodically check on the soldering prole to ensure
the soldering prole used is always conforming to
recommended soldering condition.
• If necessary, use xture to hold the LED component
in proper orientation with respect to the PCB during
soldering process.
• Proper handling is imperative to avoid excessive
thermal stresses to LED components when heated.
Therefore, the soldered PCB must be allowed to cool to
room temperature, 25 °C, before handling.
• Special attention must be given to board fabrication,
solder masking, surface plating and lead holes size and
component orientation to assure solderability.
• Recommended PC board plated through hole sizes for
LED component leads:
LED Component
Lead Size
Diagonal Plated Through-
Hole Diameter
Lead size (typ.) 0.45 × 0.45 mm
(0.018 × 0.018 in.)
0.636 mm
(0.025 in)
0.98 to 1.08 mm
(0.039 to 0.043 in)
Dambar shear-
o area (max.)
0.65 mm
(0.026 in)
0.919 mm
(0.036 in)
Lead size (typ.) 0.50 × 0.50 mm
(0.020 × 0.020 in.)
0.707 mm
(0.028 in)
1.05 to 1.15 mm
(0.041 to 0.045 in)
Dambar shear-
o area (max.)
0.70 mm
(0.028 in)
0.99 mm
(0.039 in)
Note:
Refer to application note AN1027 for more information on soldering LED
components.
0 10 20 30 40 50 60 70 80 90 100
250
200
150
100
50
TIME (SECONDS)
PREHEAT
TURBULENT WAVE
LAMINAR
HOT AIR KNIFE
TEMPERATURE (°C)
Recommended solder:
Sn63 (Leaded solder alloy)
SAC305 (Lead-free solder alloy)
Flux: Rosin ux
Solder bath temperature:
245 °C ± 5 °C (maximum peak temperature = 250 °C)
Dwell time: 1.5 sec – 3.0 sec (maximum = 3 sec)
Note: Allow for board to be suciently cooled to
room temperature before you exert mechanical force.
Figure 5. Recommended wave soldering prole
