Texas Instruments Corporation

Robert N McLellan

Anthony M Chiu

Paul Joseph Hundt

William Kevin Dennis

A method of fabricating a semiconductor device comprising the steps of providing an encapsulated semiconductor device bonded to a lead frame, providing a support ring formed of a material which softens when subjected to one of ultrasonic energy or formed of a material which softens when subjected to heat insufficient to cause sufficient expansion of said lead frame relative to said support ring to cause buckling of the leads of said lead frame, preferably thermoplastic and preferably polyphenylene sulfide, disposing leads of said lead frame over said support ring and causing said leads to embed in said support ring by applying ultrasonic energy to said support ring or by applying heat to said support ring insufficient to cause sufficient expansion of said lead frame relative to said support ring to cause buckling of the leads of said lead frame. The lead frame is preferably formed of gold plated copper, solder plate or tin plate.

Method of fabricating an ultrasonically welded plastic support ring

An electronic device (10) includes a package (16) having two posts (30) suitable for insertion in PCB holes. Package (16) presents a lengthwise molding plane (32) along which the upper portion (42) and bottom portion (44) of package (16) are mated during the molding process. Posts (30) are disposed substantially exclusively in bottom portion (44) so that posts (30) are asymmetric about lengthwise molding plane (32). Thus, even if a top mold (42a) and a bottom mold (44a) are misaligned there will be no effect on the dimensional tolerance of posts (30) and thus the tolerance of post (30) can be closely matched with a PCB hole (20) tolerance to insure a snug fit. Thus, device (10) is mounted edgewise on a PCB (18) by insertion of posts (30) into PCB holes (20) so that tips (24) of lead fingers (4 14) can be connected to PCB (18) by surfacing-mounting techniques or the like.

Integrated circuit device having improved post for surface-mount package

An electronic device (10) includes a package (16) having two posts (30) suitable for insertion in PCB holes. Package (16) presents a lengthwise molding plane (32) along which the upper portion (42) and bottom portion (44) of package (16) are mated during the molding process. Posts (30) are disposed substantially exclusively in bottom portion (44) so that posts (30) are asymmetric about lengthwise molding plane (32). Thus, even if a top mold (42a) and a bottom mold (44a) are misaligned there will be no effect on the dimensional tolerance of posts (30) and thus the tolerance of post (30) can be closely matched with a PCB hole (20) tolerance to insure a snug fit. Thus, device (10) is mounted edgewise on a PCB (18) by insertion of posts (30) into PCB holes (20) so that tips (24) of lead fingers (14) can be connected to PCB (18) by surfacing-mounting techniques or the like.

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Garland, TX, United States of America

Robert N McLellan