Browse Prior Art Database

Mixed Lead Pitch/Pad Geometry for Surface Mount Technology

IP.com Disclosure Number: IPCOM000036499D
Original Publication Date: 1989-Oct-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 2 page(s) / 51K

Publishing Venue

IBM

Related People

Cayson, B: AUTHOR [+2]

Abstract

Disclosed is a mixed lead pitch technology package which combines the advantages of two different lead pitches and/or spacings into one package.

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Mixed Lead Pitch/Pad Geometry for Surface Mount Technology

Disclosed is a mixed lead pitch technology package which combines the advantages of two different lead pitches and/or spacings into one package.

The disclosed design would be applicable for any fine lead pitch SMT device of .050" lead pitch or finer. The pad sizes, spacings or combination of the two would be calculated for optimum performance. The design allows the user increased wirability and increased yield. Yield enhancements are obtained by eliminating orientation effects associated with assembly processes, such as screening, vapor phase or infrared reflow and wave solder.

The figure illustrates how this design could be used by modifying a .025" pitch quad flat pack to incorporate .050" lead pitch on two of the four sides. Also pad sizes and/or pad spacings could be varied along a row of pads.

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