9
Precautions
Lead Forming
• The leads of an LED lamp may be preformed or cut to
length prior to insertion and soldering on PC board.
• If lead forming is required before soldering, care must
be taken to avoid any excessive mechanical stress in-
duced into the LED package. Otherwise, cut the leads
to applicable length after soldering process at room
temperature. The solder joint formed will absorb the
mechanical stress, due to lead cutting, from traveling
to the LED chip die attach and wirebond.
• For better control, it is recommended to use proper
tool to precisely form and cut the leads to applicable
length rather than doing it manually.
Soldering Conditions
• Care must be taken during PCB assembly and soldering
process to prevent damage to LED component.
• The closest manual soldering distance of the soldering
heat source (soldering iron’s tip) to the body is
1.59 mm. Soldering the LED closer than 1.59 mm might
damage the LED.
• Recommended soldering conditions:
Manual Solder
Wave Soldering Dipping
Pre-heat Temperature 105 °C Max. –
Pre-heat Time 30 sec Max. –
Peak Temperature 250 °C Max. 260 °C Max.
Dwell Time 3 sec Max. 5 sec Max.
• If necessary, use fixture to hold the LED component
in proper orientation with respect to the PCB during
soldering process.
• At elevated temperature, the LED is more susceptible
to mechanical stress. Therefore, PCB must be allowed
to cool down to room temperature prior to handling,
which includes removal of jigs, fixtures or pallet.
• 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 Plated Through
Lead Size Diagonal Hole Diameter
0.457 x 0.457 mm 0.646 mm 0.976 to 1.078 mm
(0.018 x 0.018 inch) (0.025 inch) (0.038 to 0.042 inch)
0.508 x 0.508 mm 0.718 mm 1.049 to 1.150 mm
(0.020 x 0.020 inch) (0.028 inch) (0.041 to 0.045 inch)
Note: Refer to application note AN1027 for more information on soldering LED
components.
• Wave soldering parameter must be set and maintained
according to recommended temperature and dwell
time in the solder wave. Customer is advised to daily
check on the soldering profile to ensure the soldering
profile is always conforming to recommended
soldering condition.
Notes:
1. PCB with different size and design (component density) will have different heat
mass (heat capacity). This might cause a change in temperature experienced by the
board if samewave soldering setting is used. So, it is recommended to recalibrate
the soldering profile again before loading a new type of PCB.
2. Avago Technologies’ high brightness LEDs use a high efficiency LED die with single
wire bond, as shown below. Customer is advised to take extra precaution during
wave soldering to ensure that the maximum wave temperature does not exceed 250°C.
Over-stressing the LED during soldering process might cause premature failure to the
LED due to delamination.
Note: Electrical connection between bottom surface of LED die and the lead frame material
through conductive paste of solder.
Avago Technologies LED Configuration
InGaN Device
• Over sizing of plated through hole can lead to
twisting or improper LED placement during auto
insertion. Under sizing plated through hole can lead to
mechanical stress on the epoxy lens during clinching.
