Magnetic field sensors and methods for fabricating the magnetic field sensors
First Claim
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1. A magnetic field sensor, comprising:
- a lead frame comprising a die attach pad, wherein the die attach pad comprises first and second opposing surfaces;
a magnetic field sensor circuit die proximate to the first surface of the die attach pad;
a molded capsule molded upon the die attach pad and enclosing the magnetic field sensor circuit die, wherein the molded capsule includes a cavity having an inner cavity surface, wherein a portion of the inner cavity surface is proximate to the second surface of the die attach pad, and wherein the cavity has a shape capable of retaining a liquid;
a magnet proximate to the second surface of the die attach pad and disposed within the cavity; and
a cured liquid encapsulant disposed within the cavity and configured to encapsulate the magnet within the cavity.
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Abstract
Magnetic field sensors and associated methods of manufacturing the magnetic field sensors include molded structures to encapsulate a magnetic field sensing element and an associated die attach pad of a lead frame and to also encapsulate or form a magnet or a flux concentrator.
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Citations
10 Claims
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1. A magnetic field sensor, comprising:
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a lead frame comprising a die attach pad, wherein the die attach pad comprises first and second opposing surfaces; a magnetic field sensor circuit die proximate to the first surface of the die attach pad; a molded capsule molded upon the die attach pad and enclosing the magnetic field sensor circuit die, wherein the molded capsule includes a cavity having an inner cavity surface, wherein a portion of the inner cavity surface is proximate to the second surface of the die attach pad, and wherein the cavity has a shape capable of retaining a liquid; a magnet proximate to the second surface of the die attach pad and disposed within the cavity; and a cured liquid encapsulant disposed within the cavity and configured to encapsulate the magnet within the cavity. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A magnetic field sensor, comprising:
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a lead frame comprising a die attach pad, wherein the die attach pad comprises first and second opposing surfaces; a magnetic field sensor circuit die proximate to the first surface of the die attach pad; a molded capsule enclosing the magnetic field sensor circuit die, wherein the molded capsule includes a cavity having an inner cavity surface, wherein a bottom of the inner cavity surface is proximate to the second surface of the die attach pad, and wherein the cavity has a continuous side wall extending from the bottom to form the cavity with a shape capable of retaining a liquid; and a cured liquid material disposed within the cavity, wherein the cured liquid material is filled with ferromagnetic particles to either generate a magnetic field or to concentrate a magnetic field. - View Dependent Claims (9, 10)
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Specification