| US 9,812,588 B2 | ||
| Magnetic field sensor integrated circuit with integral ferromagnetic material | ||
| Ravi Vig, Bow, NH (US); William P. Taylor, Amherst, NH (US); Paul David, Bow, NH (US); P. Karl Scheller, Bow, NH (US); and Andreas P. Friedrich, Metz-Tessy (FR) | ||
| Assigned to Allegro Microsystems, LLC, Worcerter, MA (US) | ||
| Filed by Allegro Microsystems, LLC, Worcester, MA (US) | ||
| Filed on Jan. 24, 2013, as Appl. No. 13/748,999. | ||
| Application 13/748,999 is a continuation in part of application No. 13/424,618, filed on Mar. 20, 2012. | ||
| Prior Publication US 2013/0249029 A1, Sep. 26, 2013 | ||
| This patent is subject to a terminal disclaimer. | ||
| Int. Cl. G01R 33/06 (2006.01); H01L 29/82 (2006.01); G01R 33/00 (2006.01) | ||
| CPC H01L 29/82 (2013.01) [G01R 33/0047 (2013.01); G01R 33/0052 (2013.01); G01R 33/06 (2013.01); H01L 2224/45147 (2013.01); H01L 2224/48247 (2013.01)] | 15 Claims |
| 1. A magnetic field sensor comprising:
a lead frame having a first surface and a second opposing surface;
a semiconductor die having a first surface in which a magnetic field sensing element is disposed and a second opposing surface
attached to the first surface of the lead frame;
a non-conductive mold material enclosing the die and at least a portion of the lead frame; and
a ferromagnetic mold material secured to a portion of the non-conductive mold material, wherein the ferromagnetic mold material
comprises a central aperture having a surface extending from the non-conductive mold material to an outer peripheral surface
of the ferromagnetic mold material, wherein the surface of the central aperture comprises a bend at an intermediate location
such that the surface of the central aperture has a first slope from the non-conductive mold material to the bend and a second
slope different than the first slope from the bend to the outer peripheral surface of the ferromagnetic mold material.
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