76 mm solder ball will collapse to a final height of. Total solder ball collapse after PBGA assembly and final assembly to the motherboard will be approximately 25% with the solder mask/capture pad/solder ball dimensions given above.Terpene solution cleaning is recommended if a flux that requires cleaning is used at reflow.IR convection reflow with nitrogen (and oxygen content control) is recommended especially with no-clean flux.PBGA alignment markings and fiducials will be required to target and place the PBGA on the motherboard. PBGA registration may be accomplished with edge or other package feature recognition, and mechanical centering. PBGA are picked from Jedec-specified shipping trays. This configuration acts as a thermal heat spreader and can significantly improve the thermal performance of the design. Any plane used for thermal dissipation should be designed to be a min of 2oz copper to increase thermal conductivity away from the PBGA. This is typically accomplished with a grid of vias that are also used to make the electrical connection for the thermal balls. The application board should allow for a low thermal resistance path from the thermal balls to a plane in the board. In the case of the SHARC PBGA, a group of balls in the center of the ball grid are designated as "thermal balls" in addition to their electrical purpose.Solder paste particle size is also determined by need for assembly of fine pitch components. Generally, the paste height is determined by the screening/assembly of fine pitch components on the motherboard in the same pass. 004" will be successful as PBGA is not terribly sensitive to paste height/volume. 008" screened solder paste height is recommended, but even. Suitable solder pastes for screening are eutectic 63/37:SnPb, 60/40:SnPb, or 62/36/2:SnPbAg.Ball pad finish can be copper with a protective anti-oxident chemical coat such as Entek, gold (electrolytic or electroless), or HASL (hot air solder leveling).Ball pad size may vary depending on the solder mask registration tolerance (this variance can be substantial between dry film/liquid apply, method of application and thickness).Note: all packages are solder mask defined (SMD) except ADSP-TS201S Note: For data sheet revisions published after June 2005, recommended solder mask opening and ball pad size information is available in the Outline Dimensions figure in the data sheet. Dimensions for the solder mask opening and ball pad size for some of ADI's Processors in a BGA package are given below:.Capture pad/capture pad opening on customer's board should equal the solder mask opening OR ball pad size on the processor - whichever is smaller.Motherboard design and assembly recommendations: Surface Mount Assembly Recommendations for Plastic Ball Grid Array (PBGA) Packages
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