Kenneth E Ellis

US Patent:

6573818, Jun 3, 2003

Filed:

Mar 31, 2000

Appl. No.:

09/540618

Inventors:

Timothy J. Klemmer - Pittsburgh PA
Robert Bruce Van Dover - Maplewood NJ
Kenneth Alexander Ellis - North Plainfield NJ
Ashraf Wagih Lotfi - Rowlett TX

Assignee:

Agere Systems, Inc. - Allentown PA

International Classification:

H01F 2702

US Classification:

336 83, 336200

Abstract:

The present invention is a planar spiral inductor a top magnetic layer a bottom magnetic layer; and a plurality of conductive coils disposed between said top magnetic layer and said bottom magnetic layer. A significant difference from prior art is that the top and bottom magnetic layers have their centers effectively cut out using lithographic techniques or other techniques to frame the core of the conductive spirals. An advantage of this structure over the prior art is that when magnetic anisotropies other than shape are kept small, then the magnetic configuration will produce a magnetostatic shape anisotropy such that the easy axis (low energy direction of magnetization) lies parallel to the legs of a rectangular frame or the circumference of a circular frame, as will be described. During operation of the inductor, the field produced by the coils flows in a radial direction and will be perpendicular to the easy axis direction thereby causing magnetization reversal to occur by rotation while advantageously utilizing the full structure in this mode.