# US 11,444,209 B2 · Magnetic field sensor integrated circuit with an integrated coil enclosed with a semiconductor die by a mold material > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,444,209 B2 - Document ID: US11444209B2 - Status: Granted - Kind: B2 - Application number: 17/130,085 - Filed: 2020-12-22 - Published: 2021-04-15 - Granted: 2022-09-13 - Earliest claimed: 2012-03-20 - Assignees: Allegro MicroSystems, LLC - Applicants: Allegro MicroSystems, LLC - Inventors: Ravi Vig; William P. Taylor; Paul A. David; P. Karl Scheller; Andreas P. Friedrich - Web page: https://patentgrep.com/patent/US11444209B2 ## CPC - H10D 48/40: Devices controlled by magnetic fields - G01D 5/147: {influenced by the movement of a third element, the position of Hall device and the source of magnetic field being fixed in respect to each other} - G01R 33/0047: {Housings or packaging of magnetic sensors (packaging of semiconductor devices H10W99/00); Holders} - G01R 33/0052: {Manufacturing aspects; Manufacturing of single devices, i.e. of semiconductor magnetic sensor chips (devices based on galvano-magnetic effect or the like H10N50/85)} - G01R 33/06: using galvano-magnetic devices - G01D 2205/40: Position sensors comprising arrangements for concentrating or redirecting magnetic flux - G01R 15/207: {Constructional details independent of the type of device used} - H10W 72/5525: {comprising copper [Cu]} - H10W 72/865: {Die-attach connectors and bond wires} - H10W 90/756: {between a chip and a stacked lead frame, conducting package substrate or heat sink} - H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES - G01D: MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR - G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12) - H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10 ## Abstract A magnetic field sensor includes a lead frame, a semiconductor die, a conductive coil, a mandrel, and a non-conductive mold material. The lead frame has a first surface, a second opposing surface, at least one slot, and a plurality of leads. The semiconductor die has 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. The conductive coil is secured to the second surface of the lead frame and configured to operate as a back bias magnet to provide a magnetic field used to detect movement of a target. The coil is would around the mandrel and the mandrel is comprised of a ferromagnetic material. The non-conductive mold material encloses the die, the conductive coil, the mandrel, and at least a portion of the lead frame. ## Claims ### Claim 1 A magnetic field sensor comprising: a lead frame having a first surface, a second opposing surface, at least one slot, and a plurality of leads; 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 conductive coil directly attached to the second surface of the lead frame with adhesive and configured to operate as a back bias magnet to provide a magnetic field used to detect movement of a target; a mandrel around which the coil is disposed, wherein the mandrel is comprised of a ferromagnetic material, wherein the mandrel is directly attached to the second surface of the lead frame with adhesive; and a non-conductive mold material enclosing the die, the conductive coil, the mandrel, and at least a portion of the lead frame. ### Claim 2 (depends on 1) The magnetic field sensor of claim 1 further comprising a ferromagnetic mold material secured to a portion of the non-conductive mold material. ### Claim 3 (depends on 2) The magnetic field sensor of claim 2 wherein the ferromagnetic mold material is a soft ferromagnetic mold material. ### Claim 4 (depends on 2) The magnetic field sensor of claim 2 wherein the ferromagnetic mold material is a hard ferromagnetic mold material. ### Claim 5 (depends on 4) The magnetic field sensor of claim 4 wherein the hard ferromagnetic material comprise at least one of a ferrite, a SmCo alloy, a NdFeB alloy, a thermoplastic polymer with hard magnetic particles, or a thermoset polymer with hard magnetic particles. ### Claim 6 (depends on 1) The magnetic field sensor of claim 1 wherein the at least one slot in the lead frame is substantially vertically aligned with respect to the magnetic field sensing element. ### Claim 7 (depends on 1) The magnetic field sensor of claim 1 wherein the lead frame comprises a securing mechanism to enhance attachment of the non-conductive mold material to the lead frame. ### Claim 8 (depends on 7) The magnetic field sensor of claim 7 wherein the securing mechanism comprises a portion of the lead frame that extends beyond the non-conductive mold material. ### Claim 9 (depends on 1) The magnetic field sensor of claim 1 wherein the magnetic field sensing element comprises a Hall effect element. ### Claim 10 (depends on 1) The magnetic field sensor of claim 1 wherein the magnetic field sensing element comprises a magnetoresistive element. ### Claim 11 (depends on 10) The magnetic field sensor of claim 10 wherein the magnetoresistive element comprises one or more of a GMR element, a AMR element, a TMR element, and a MTJ element. ### Claim 12 (depends on 1) The magnetic field sensor of claim 1 further comprising at least one passive component coupled to at least two of the plurality of leads and spaced from the non-conductive mold material. ### Claim 13 (depends on 12) The magnetic field sensor of claim 12 wherein the at least one passive component comprises a capacitor. ### Claim 14 (depends on 1) The magnetic field sensor of claim 1 wherein at least one lead comprises a first lead portion having an end and a second lead portion having an end spaced from and proximate to the end of the first lead portion, wherein the magnetic field sensor further comprises a passive component coupled between the end of the first lead portion and the end of the second lead portion such that the passive component is electrically connected in series with the at least one lead, wherein the passive component is enclosed by the non-conductive material. ### Claim 15 (depends on 14) The magnetic field sensor of claim 14 wherein passive component comprises a resistor. ### Claim 16 (depends on 1) The magnetic field sensor of claim 1 further comprising a molded ferromagnetic suppression device spaced from the non-conductive mold material and enclosing a portion of at least one of the plurality of leads.