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Reply To: | TechNet E-Mail Forum. |
Date: | Wed, 27 May 1998 09:54:22 -0500 |
Content-Type: | text/plain |
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All,
I luckely found some calculations for determining pin deflection, hole
diameter, pin length, hold (yes HOLD) diameter, etc. for Testing Fine
pitch devices (.010", .012") and BGAs.
Is anyone familiar with these formulas?
HSmin = SD + PT (tanO)
0 = sin-1 (Pd/Pl)
HSmin = (SD + PT)(PD/PL)
LEGEND
HSmin - min hold diameter
SD - shaft diameter
PT - plating thickness
0 - angle of deflection
PD - pin deflection
PL - pin length
Can I use these formulas to determine if testability is feasible, for
a very high dense assembly {4 - 600 I/O BGAs with 30 - .020" pitch
devices (160-pin nominal) in a 9 x 7 form factor}. I feel I am
missing several pieces to the overall formula picture. Can someone
advise where I can obtain the rest of the equation.
John Gulley
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