The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 17, 1984
Filed:
Jun. 03, 1982
William O Rogers, Tempe, AZ (US);
Motorola, Inc., Schaumburg, IL (US);
Abstract
An improved molded-in insulated bushing is provided to electrically isolate the mounting fastener used to attach the metallic heat spreader of a semiconductor power device to an external heat sink. The bushing has at one end a flange protruding from one surface of the heat spreader and of sufficient height to exceed the required flash-over voltage. The other end fills a chamfered portion of the heat spreader, and is flush with or relieved from the heat spreader surface which contacts the external heat sink. This shape increases the surface flash-over distance and voltage above that of bushings of the prior art and retains the bushing in the heat spreader. The bushing is advantageously formed during molding of the plastic device encapsulation, but is separated from the encapsulation so that mounting forces are not transmitted through the encapsulation to the semiconductor die and lead wires.