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:
Oct. 05, 1999
Filed:
Aug. 19, 1997
Allegro MicroSystems, Inc., Worcester, MA (US);
Abstract
A magnetic field sensor assembly has a magnet, a semiconductor sensor and a metal leadframe encapsulated in a plastic package to form a semiconductor integrated circuit. A metal leadframe has a die attach pad on which the sensor is secured and an assembly having one or more projections for securing the magnet in close proximity to the sensor. The leadframe is made from a metal having sufficient spring tension so that the assembly having the projections will secure the magnet. The sensor is adjacent to a ferromagnetic object and will detect a change in magnetic field caused by the ferromagnetic object. Only a thin layer of the plastic package covers the sensor thus reducing the distance between the sensor and the ferromagnetic object but still maintaining an air gap between the plastic package and the ferromagnetic object sufficient to allow passage of the ferromagnetic object.