Printed Circuit Board Assembly & PCB Design SMT Electronics Assembly Manufacturing Forum

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


LGA Processing

Views: 1819

#48761

LGA Processing | 29 March, 2007

Hello,

I searched the forums and found little specific info on LGAs with interior lands. This is not a QFN with a center pad. This is a multi-row BGA without solderballs.

I'm looking for recommendations on PCB land to part land ratio, stencil aperture size/shape and any other helpful tips. Placing the part without squishing paste into a bridging condition is also a concern I have.

The part we are looking at is the Renesas PN H838076. It's an LGA85 package with 0.65mm pitch.

Any help appreciated.

reply »

#48769

LGA Processing | 29 March, 2007

PCB land to part land ratio - 1:1 Stencil aperture size - 1:1 with PCB land Stencil aperture shape - same as PCB land

reply »

#48791

LGA Processing | 30 March, 2007

And how about the queston: http://www.smtnet.com/Forums/index.cfm?fuseaction=view_thread&CFApp=1&Thread_ID=11592&mc=7 We face a big problem with this matter right know. /

reply »

#48793

LGA Processing | 30 March, 2007

Question: Does this formula apply even for the small LGA:s like LGA36 6.5 x 3.5 x 0.6 mm pad size 0.35mm pitch 0.60mm? We use a 0.13 mm stencil thichess beacuse on the same board there is some P.I.P comps. The board dimensions is 35 x 50 mm on a panel with 24x these bastards. /Sincererly

reply »

#48795

LGA Processing | 31 March, 2007

Mika: Read the article posted by Manuel R in your thread that you reference. It goes into great detail on stencil apertures.

reply »

Precision Auger Dispense Pump

Used PCB Equipment - AdoptSMT