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.

•  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 

1.59mm.  Soldering  the  LED  using  soldering  iron  tip 

closer than 1.59mm might damage the LED.

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’ 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 250°C and the 

solder  contact  time  does  not  exceeding  3sec.  Over-stressing  the 

LED during soldering process might cause premature failure to the 

LED due to delamination.

Avago Technologies LED configuration

1.59mm

•  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

250 °C Max.

260 °C Max.

Dwell time

3 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 

maintained  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.

 

Note: Electrical connection between bottom surface of LED die and 

the lead frame is achieved through conductive paste.

•  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.

CATHODE

ANODE

AlInGaP Device

InGaN Device