7

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 effectively 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 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 same wave soldering

setting is used. So, it is recommended to re-calibrate the soldering

profile again before loading a new type of PCB.

2. Avago Technologies’ AllnGaP high brightness LED are using 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 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 configuration

Any alignment fixture that is being applied during

wave soldering should be loosely fitted 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 fixture 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 reflow 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 difficulty 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

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 profile to ensure that it is always

conforming to recommended soldering conditions.