Lead frames and method of making same

Claim 2

A stamped and formed transistor lead frame comprising: a mounting plate portion having a mounting surface upon which a transistor is adapted to be mounted, said surface defining a first plane, first, second, and third leads, said leads having free ends which are spaced from said mounting plate portions, said leads having intermediate portions which extend parallel to each other and towards said mounting plate portion, said leads being in a second plane which is parallel to, and spaced from, said first plane, said leads having inner ends which are proximate to said mounting plate portion, said first lead being between said second and third leads, a first lead transition section which is integral with said mounting plate portion and said inner end of said first lead, said first lead transition section extending between said first and second planes, said second and third leads having second and third lead transition sections extending divergently from said inner ends of said second and third leads, contact arms extending convergently from said second and third lead transition sections towards said mounting plate portion, said contact arms having contact arm ends which are spaced apart and adjacent to said mounting surface whereby a transistor can be positioned on said mounting plate portion beneath said contact arm ends and said arm ends can be bonded to said transistor to form electrical connections thereto.

Claim 3

A lead frame as set forth in claim 1 including a tie bar extending between said intermediate portions of said leads.

Claim 4

A lead frame as set forth in claim 2, said lead frame having been formed from stock metal having a stepped profile, said leads, said transition sections, and said contact arms having been formed from a thin section of said stock, said mounting plate portion having been formed from a relatively thick portion of said stock.

Claim 5

A lead frame as set forth in claim 3, said mounting surface having a coating of solder thereon and the surfaces of said contact arms which are opposed to said mounting surface having a coating of solder thereon.

Claim 6

A stamped and formed transistor lead frame comprising: a mounting plate portion having a mounting surface upon which a transistor is adapted to be mounted, said surface defining a first plane, first, second, and third leads, said leads having free ends which are spaced from said mounting plate portions, said leads having intermediate portions which extend parallel to each other and towards said mounting plate portion, said leads being in a second plane which is parallel to, and spaced from, said first plane, said leads having inner ends which are proximate to said mounting plate portion, said first lead being between said second and third leads, a first lead transition section which is integral with said mounting plate portion and said inner end of said first lead, said first lead transition section extending between said first and second planes, a second lead transition section extending obliquely from said inner end of said second lead away from said first lead, said second lead transition section defining a plane which extends transversely of said first and second planes and having an upper edge which lies substantially in said second plane and a lower edge which lies substantially in said first plane, a second lead contact arm extending from, and integral with, said upper edge of said second lead transition section, said second lead contact arm extending in said second plane obliquely towards said mounting portion and downwardly towards said mounting portion, said third lead being generally similar to, and a substantial mirror image of, said second lead, said second lead contact arm and the contact arm of said third lead having contact arm ends which are spaced apart adjacent to said mounting portion whereby, a transistor can be positioned on said mounting plate portion beneath said contact arm ends soldered to said contact arm ends and said mounting portion.

Claim 7

A stamped and formed transistor lead frame comprising: a mounting plate portion having a mounting surface upon which a transistor is adapted to be mounted, said surface defining a first plane, first, second, and third leads, said leads having free ends which are spaced from said mounting plate portions, said leads having intermediate portions which extend parallel to each other and towards said mounting plate portion, said leads being in a second plane which is parallel to, and spaced from, said first plane, said leads having inner ends which are proximate to said mounting plate portion, said first lead being between said second and third leads, a first lead transition section which is integral with said mounting plate portion and said inner end of said first lead, said first lead transition section extending between said first and second planes, a second lead transition section extending obliquely from said inner end of said second lead away from said first lead, said second lead transition section defining a plane which extends transversely of said first and second planes and having an upper edge which lies substantially in said second plane and a lower edge which lies substantially in said first plane, a second lead contact arm extending from, and integral with, said upper edge of said second lead transition section, said second lead contact arm extending in said second plane obliquely towards said mounting portion and downwardly towards said mounting portion, said third lead being generally similar to, and a substantial mirror image of, said second lead, said second lead contact arm and the contact arm of said third lead having contact arm ends which are spaced apart adjacent to said mounting portion whereby, a transistor can be positioned on said mounting plate portion beneath said contact arm ends soldered to said contact arm ends and said mounting portion.