SMD Device-LED

SMD devices are usually moisture/reflow sensitive. Moisture from atmospheric humidity enters permeable packaging materials by diffusion. Assembly processed used to solder SMD packages to PCBs expose the entire package body to temperature between 160C – 260C. During solder reflow, rapid moisture expansion can result in package cracking, delamination of critical interfaces within the package, or damaged gold wire.

Important: Do not store LEDs in an environment where high humidity or acidic/basic chemicals are present, as they will degrade the LED’s metallic surfaces.

Soldering:   Do not apply stress to the leads when the component is heated above 85°C, otherwise internal wire bonds may be damaged.

  1. SMD products must be mounted according to specified soldering pad patterns.
  2. Manual soldering is not recommended unless necessary such as when repair or rework is required.
  3. Soldering iron power shall not exceed 30 W.
  4. The recommended maximum temperature for lead and unlead soldering is 300c and 350c respective soldering temperature is 280℃ for no more than 3 seconds.

Heat Dissipation:   Optimal usage of high-power LED devices requires careful design by the end-user to optimize heat dissipation, such as increasing the size of the metal backing around the soldering pad. Refer to the product datasheet for specific design recommendations regarding heat dissipation.

During soldering, SMD components should be mounted such that the leads are placed perpendicular to the direction of PCB travel to insure the solder on each lead melts simultaneously during reflow.

1. Protective current-limiting resistors may be necessary to operate the LEDs within the specified range.
2. LEDs mounted in parallel should each be placed in series with its own current-limiting resistor.

                                                                                    LED MOUNTING METHOD

1. The lead pitch of the LED must match the pitch of the mounting holes on the PCB during component placement. Lead-forming may be required to insure the lead pitch matches the hole pitch. Refer to the figure below for proper lead forming procedures.


We recommend manual soldering operations only for repair and rework purposes. The soldering iron should not exceed 30W in power. The maximum soldering temperature is 300°C for Pb-Sn solder and 350°C for lead-free solder for normal lamps and dis plays. For blue (425nm), blue-green (525nm), and all white LEDs, the maximum soldering iron temperature is 280°C. Do not place the soldering iron on the component for more than 3 seconds.

The tip of the soldering iron should never touch the lens epoxy. Do not apply stress to the leads when the component is heated above 85°C, otherwise internal wire bonds may be damaged. After soldering, allow at least three minutes for the component to cool to room temperature before further operations.


Through-hole LEDs are incompatible with reflow soldering. If the LED will undergo multiple soldering passes or face other processes where the part may be subjected to intense heat, please check with King bright for compatibility.


In case of misalignment and re-position is required, do not force the LED while applying a soldering iron. The part should be first de-soldered, and then the LED may be re-soldered with the aid of a holder to place it correctly.

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