7

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 standoff.

• Recommended soldering conditions:

Wave Soldering

Manual Solder

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.

• 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 profile to ensure

the soldering profile used is always conforming to

recommended soldering condition.

• If necessary, use fixture 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

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.

Figure 11. Recommended wave soldering profile.

LAMINAR WAVE

BOTTOM SIDE

OF PC BOARD

HOT AIR KNIFE

TURBULENT WAVE

FLUXING

PREHEAT

0

10

20

30

50

100

150

200

250

30

40

50

TIME – SECONDS

60

70

80

90 100

TOP SIDE OF

PC BOARD

CONVEYOR SPEED = 1.83 M/MIN (6 FT/MIN)

PREHEAT SETTING = 150

°C (100°C PCB)

SOLDER WAVE TEMPERATURE = 245

°C

AIR KNIFE AIR TEMPERATURE = 390

°C

AIR KNIFE DISTANCE = 1.91 mm (0.25 IN.)

AIR KNIFE ANGLE = 40

°

NOTE: ALLOW FOR BOARDS TO BE

SUFFICIENTLY COOLED BEFORE EXERTING

MECHANICAL FORCE.