8
Precautions:
Lead Forming:
• The leads of an LED lamp may be preformed or cut to
length prior to insertion and soldering on PC board.
• 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.
• If manual lead cutting is necessary, cut the leads after
the soldering process. The solder connection forms
a mechanical ground which prevents mechanical
stress due to lead cutting from traveling into LED
package. This is highly recommended for hand solder
operation, as the excess lead length also acts as small
heat sink.
Soldering and Handling:
• Care must be taken during PCB assembly and
soldering process to prevent damage to the LED
component.
• LED component may be e ectively hand soldered
to PCB. However, it is only recommended under
unavoidable circumstances such as rework. The
closest manual soldering distance of the soldering
heat source (soldering iron’s tip) to the body is 1.59
mm. Soldering the LED using soldering iron tip closer
than 1.59 mm might damage the LED.
1.59mm
AlInGaP Device
CATHODE
InGaN Device
ANODE
Note:
1. PCB with di erent size and design (component density) will have
di erent heat mass (heat capacity). This might cause a change in
temperature experienced by the board if same wave soldering
setting is used. So, it is recommended to re-calibrate the soldering
pro le again before loading a new type of PCB.
2. Avago Technologies’ AllnGaP high brightness LED are using high
e ciency 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 260° C and
the solder contact time does not exceeding 5 sec. Over-stressing the
LED during soldering process might cause premature failure to the
LED due to delamination.
Avago Technologies LED con guration
• Any alignment xture that is being applied during
wave soldering should be loosely tted and should
not apply weight or force on LED. Non metal material
is recommended as it will absorb less heat during
wave soldering process.
• At elevated temperature, LED is more susceptible to
mechanical stress. Therefore, PCB must allowed to cool
down to room temperature prior to handling, which
includes removal of alignment xture or pallet.
• If PCB board contains both through hole (TH) LED and
other surface mount components, it is recommended
that surface mount components be soldered on the
top side of the PCB. If surface mount need to be on the
bottom side, these components should be soldered
using re ow soldering prior to insertion the TH LED.
• Recommended PC board plated through holes (PTH)
size for LED component leads.
LED component
lead size Diagonal
Plated through
hole diameter
0.45 x 0.45 mm
(0.018x 0.018 inch)
0.636 mm
(0.025 inch)
0.98 to 1.08 mm
(0.039 to 0.043 inch)
0.50 x 0.50 mm
(0.020x 0.020 inch)
0.707 mm
(0.028 inch)
1.05 to 1.15 mm
(0.041 to 0.045 inch)
• Over-sizing the PTH can lead to twisted LED after
clinching. On the other hand under sizing the PTH can
cause di culty inserting the TH LED.
Refer to application note AN5334 for more information about
soldering and handling of high brightness TH LED lamps.
• ESD precaution must be properly applied on the
soldering station and personnel to prevent ESD
damage to the LED component that is ESD sensitive.
Do refer to Avago application note AN 1142 for details.
The soldering iron used should have grounded tip to
ensure electrostatic charge is properly grounded.
• Recommended soldering condition:
Wave
Soldering [1, 2]
Manual Solder
Dipping
Pre-heat temperature 105° C Max. –
Preheat time 60 sec Max –
Peak temperature 260° C Max. 260° C Max.
Dwell time 5 sec Max. 5 sec Max
Note:
1. Above conditions refers to measurement with thermocouple
mounted at the bottom of PCB.
2. It is recommended to use only bottom preheaters in order to
reduce thermal stress experienced by LED.
• Wave soldering parameters must be set and main-
tained according to the recommended temperature
and dwell time. Customer is advised to perform
daily check on the soldering pro le to ensure that
it is always conforming to recommended soldering
conditions.