(TB334) Guidelines Soldering Surface Mount Components Boards Spec

The Datasheet Archive - 100 Million Datasheets from 7500 Manufacturers.

(TB334) Guidelines Soldering Surface Mount Components Boards Spec

Datasheet Thumbnail

Top Searches for this datasheet

(TB334) Guidelines Soldering Surface Mount Components Boards
Special care must taken when soldering surface mount components printed circuit (PC) board. There commonly used techniques soldering surface mount components (SMCs) board. They are: Infrared (IR) Forced Convection (FC) Vapor Phase Reflow (VP) Wave Soldering (WS)
Infrared, Forced Convection Vapor Phase reflow preferred soldering methods. Wave soldering typically involves increased heating rates, higher temperatures increased flux exposure. primary phases reflow process are: flux activation, melting solder particles solder paste, wetting surfaces joined, solidifying solder into strong metallurgical bond. Optimum fusing component leads with solder paste board achieved when leads attain melting temperature plated solder alloy. maximum heating cooling rates (ramp rate) should controlled avoid thermal shock SMCs.
Reflow
reflow technique involves transferring thermal energy supplied infrared lamps circuit board, solder, component. This heating approach basic form essentially line-of-sight surface-heating technique. Therefore, amount thermal energy absorbed varies with board size, component size, component orientation, materials used. surface temperature board uniform throughout soldering process board edges tend 10oC 20oC higher than temperature center board. Component overheating possible care taken ensure temperature remains relatively even across board.
Forced Convection
Forced Convection reflow technique involves transferring thermal energy supplied heated forced blown circuit assembly from above and/or below. This method some advantages over reflow processing. Board heating more uniform compared with process. Component overheating thermal shock also less likely, components
©2002 Fairchild Semiconductor Corporation
Rev.
tend change temperature rate closer that PCB. Assembly size, component size, component orientation, component material have less effect soldering process with forced convection compared Reflow process.
Vapor Phase Reflow
vapor phase reflow technique uses vapor from boiling inert fluorocarbon liquid. heat condensation provides thermal constraint dependent fluorocarbon liquid selected. typical fluorocarbon liquid used industry boiling point 215oC. board temperature exposure should very uniform using this method. temperature gradient across surface board should minimal. component location design rules even heating sensitive rules reflow soldering process.
Solder Profile Development
Heating Rate avoid thermal shock sensitive components maximum heating rate should controlled. desirable hold heating rate less than 5oC/s. Preheat Zone Boards should preheated prior reflow step. Over-baking solder paste exceeding glass transition temperature epoxy FR-4 boards should avoided. temperature component board should range 105oC 145oC depending upon reflow method used. Time above Solder Melting Point recommended that solder joint kept above melting point allow sufficient time solder flow, lands, leads. Total time above 180oC. could range from sec. sec. depending upon type equipment used, board size, component size, etc. Extended duration above solder melting point damage board sensitive components. This value should minimized, should also chosen allow good solder joint formation. Most solder manufacturers will provide recommended reflow profile based solder composition flux chemistry. Peak Reflow Temperature peak temperature solder joint during reflow should high enough adequate flux action solder flow obtain good wetting. maximum peak temperatures 215oC 220oC Infrared Forced Convection reflow 215oC 219oC Vapor Phase reflow depending package dimensions (Refer J-STD-020A). Exposure time peak temperatures should minimized. Cooling Rate cooling rate solder joint after reflow important. Faster cooling rates, result smaller grain size solder, higher fatigue resistance. However, care should taken avoid excessive temperature gradient resulting potential component damage mechanical stress.
Summary Soldering Precautions
soldering process create thermal stress semiconductor component. melting temperature solder higher than maximum rated operating temperature device. amount time device peak reflow temperature should minimized assure device reliability. Therefore, following precautions should always observed order minimize thermal stress which devices subjected. Always preheat device. Keep delta temperature between preheating phase soldering phase less than
©2002 Fairchild Semiconductor Corporation
Rev.
100oC. Failure preheat device result excessive thermal stress which damage device. maximum temperature gradient should less than second when transitioning from preheating phase soldering phase. maximum soldering temperature time wave soldering must exceed 260oC leads case device. peak temperature soldering process should least 30oC higher than melting point solder chosen. Forced cooling after soldering phase will increase temperature gradient result latent failures mechanical stresses. Mechanical stress shock should avoided during cooling.
©2002 Fairchild Semiconductor Corporation
Rev.
TRADEMARKS
following registered unregistered trademarks Fairchild Semiconductor owns authorized intended exhaustive list such trademarks.
ACEx Bottomless CoolFET CROSSVOLT DenseTrench DOME EcoSPARK E2CMOSEnSignaFACT FACT Quiet Series
DISCLAIMER
FAST FASTr FRFET GlobalOptoisolator HiSeC ISOPLANAR LittleFET MicroFET MicroPak
MICROWIRE OPTOLOGIC OPTOPLANAR PACMAN Power247 PowerTrench QFET Optoelectronics Quiet Series
SILENT SWITCHER SMART START UltraFET STAR*POWER Stealth SuperSOT-3 SuperSOT-6 SuperSOT-8 SyncFET TinyLogic TruTranslation
STAR*POWER used under license
FAIRCHILD SEMICONDUCTOR RESERVES RIGHT MAKE CHANGES WITHOUT FURTHER NOTICE PRODUCTS HEREIN IMPROVE RELIABILITY, FUNCTION DESIGN. FAIRCHILD DOES ASSUME LIABILITY ARISING APPLICATION PRODUCT CIRCUIT DESCRIBED HEREIN; NEITHER DOES CONVEY LICENSE UNDER PATENT RIGHTS, RIGHTS OTHERS.
LIFE SUPPORT POLICY FAIRCHILDS PRODUCTS AUTHORIZED CRITICAL COMPONENTS LIFE SUPPORT DEVICES SYSTEMS WITHOUT EXPRESS WRITTEN APPROVAL FAIRCHILD SEMICONDUCTOR CORPORATION. used herein: critical component component life Life support devices systems devices support device system whose failure perform systems which, intended surgical implant into reasonably expected cause failure life body, support sustain life, whose support device system, affect safety failure perform when properly used accordance with instructions provided labeling, effectiveness. reasonably expected result significant injury user. PRODUCT STATUS DEFINITIONS Definition Terms Datasheet Identification Advance Information Product Status Formative Design First Production Definition This datasheet contains design specifications product development. Specifications change manner without notice. This datasheet contains preliminary data, supplementary data will published later date. Fairchild Semiconductor reserves right make changes time without notice order improve design. This datasheet contains final specifications. Fairchild Semiconductor reserves right make changes time without notice order improve design. This datasheet contains specifications product that been discontinued Fairchild semiconductor. datasheet printed reference information only.
Preliminary
Identification Needed
Full Production
Obsolete
Production
Rev.

(TB334) Guidelines Soldering Surface Mount Components Boards Spec

Top Searches for this datasheet

Other recent searches