APPLICATION NOTES FOR SMD LEDs Storage conditions 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 160 - 260. During solder reflow, rapid moisture expansion can result in package cracking, delamination of critical interfaces within the package, or damaged gold wire. 1. Scope: Application notes listed in this document apply to SMD products include the KA, KP, KM, KPK, and KT series. 2. Unopened moisture barrier bag (MBB) shall be stored at temperature below 40 with humidity below 90%RH. 3. After the MBB has been opened, the LEDs should be used according to the floor life specified in the table below. 3.1IPC/JEDEC J-STD-020 Moisture Sensitivity Levels FLOOR LIFE LEVEL TIME CONDITIONS 30/85% RH 1 Unlimited 2 1 year 30/60% RH 2a 4 weeks 30/60% RH 3 168 hours 30/60% RH 30/60% RH 4 72 hours 5 48 hours 30/60% RH 30/60% RH 5a 24 hours 6 Time on Label(TOL) 30/60% RH 4. If the Humidity Indicator Card (HIC)s 10 % mark has changed, or the LEDs have not been used within the floor life specified, they should be baked with the following conditions to reset the floor life: Type Temperature Humidity Bake Time 603 When still in carrier tape <5%RH 100H When out of carrier tape 110 / 10H * Not more than once 5. Do not store LEDs in an environment where high humidity or acidic/basic chemicals are present, as they will degrade the LEDs metallic surfaces. 6. LED leadframe and soldering pads (cathode and anode) are plated with gold, tin, or other metals. Under long-term exposure to open air, the exposed pins and pads may become oxidized causing poor solderability. Therefore opened but unused parts must be stored in sealed containers. Suggest to store unused parts in the original moisture barrier bag. 7. Moisture control for components already mounted on PCBIf the PCB will not undergo additional reflow soldering or high-temperature processes, then no special treatment is required for the mounted moisture-sensitive SMD components. If the PCB will undergo multiple reflow soldering or other Rev No: V9 1/22/2015 Page 1 www.kingbright.com APPLICATION NOTES FOR SMD LEDs high-temperature processes, including rework, then the SMD component s cumulative exposure time until the final high-temperature process must be controlled to within the specified time limit. Soldering 1. Do not apply stress to the leads when the component is heated above 85C, otherwise internal wire bonds may be damaged. 2. SMD products must be mounted according to specified soldering pad patterns. Refer to the product datasheet for details. Solder paste must be evenly applied to each soldering pad to insure proper bonding and positioning of the component. 3. After soldering, allow at least three minutes for the component to cool to room temperature before further operations. 4. The SMD LED Iron Soldering(with 1.5mm Iron tip ) condition: Temperature of Soldering Iron Maximum Soldering time <=350 3s 5. Soldering Profile With Pb-Sn Solder (Heating) to 10s ) 230C (Peak Temperature) C ( T 210C e r to 30s u t a r e p 100 to 160C m 60 to120s e T (Preheating) e c a f r u S e g a k c a P Time(s) 6. Lead-Free Soldering Profile 300 (C) 10 s max 260C max. 250 230C. 4C/s max 4C/s max 200 150~180C 4C/s max 150 60~120s 30~50s NOTE: 100 1.We recommend the reflow temperature 245C(+/-5C).The maximum soldering temperature should be limited to 260C. 2.Don t cause stress to the epoxy resin while it is exposed 50 to high temperature. 25C 3.Number of reflow process shall be 2 times or less. 0 0 50 100 150 200 250 300 (sec) Time Rev No: V9 1/22/2015 Page 2 www.kingbright.com Temperature