Sensor and method of providing a sensor

• US 9,228,860 B2
• Filed: 12/14/2011
• Issued: 01/05/2016
• Est. Priority Date: 07/14/2006
• Status: Active Grant

• Current Assignee: Allegro Microsystems Incorporated (Sanken Electric Company Limited)
• Original Assignee: Allegro Microsystems Incorporated (Sanken Electric Company Limited)
• Inventors: Sharma, Nirmal, Ararao, Virgil, Taylor, William P., Doogue, Kirsten, Gagnon, Jay, Magpantay, Leonardo T., Engle, Raymond W.
• Primary Examiner(s): Dinh, Tuan T
• Application Number:
  US13/325,162
• Publication Number:
  US 20120086090A1
• Time in Patent Office: 1,483 Days
• Field of Search: 361760-764, 361782-784, 361/803, 361/813
• US Class Current: 1/1
• CPC Class Codes: G01D 11/245 Housings for sensors
• CPC Class Codes: G01R 33/07 Hall effect devices
• CPC Class Codes: G01R 33/09 Magnetoresistive devices
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/48257 connecting the wire to a die pad of the item
• CPC Class Codes: H01L 23/49589 Capacitor integral with or on the leadframe
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00012 Relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/10253 Silicon [Si]
• CPC Class Codes: H01L 2924/181 Encapsulation
• CPC Class Codes: H01L 2924/19105 in a side-by-side arrangement on a common die mounting substrate
• CPC Class Codes: H01L 2924/3011 Impedance
• CPC Class Codes: H10N 52/00 Hall-effect devices integrated devices or assemblies of multiple devices H10N59/00
• CPC Class Codes: H10N 52/80 Constructional details

Abstract

Methods and apparatus for a magnetic field sensor in a molded IC package having a magnetic field sensing element in a die with a component coupled to a leadframe at a downset area. In embodiments, a thickness of the leadframe in the downset area is less than a thickness of the leadframe in a non-downset area adjacent to the downset area.

Claims

1. A magnetic field sensor in a molding IC package, comprising:

a die;

a magnetic field sensing element in the die;

a leadframe having opposed first and second surfaces, the leadframe supporting the die on the first surface;

lead fingers to provide electrical connections to the leadframe and to the die;

a first one of the lead fingers extending from the leadframe in a single piece of material to provide an external lead of the IC package, wherein the die supporting portion of the leadframe is formed from the single piece of material; and

a component coupled to the leadframe and coupled to a first one of the lead fingers formed from the single piece of material such that the component is an integrated part of the IC package providing the sensor to minimize a an air gap between the IC package and an object of interest;

wherein the leadframe includes a downset area at which the component is coupled to the leadframe, and

wherein a thickness of the leadframe in the downset area is less than a thickness of the leadframe in a non-downset area adjacent to the downset area;

wherein the first one of the lead fingers includes the downset area to receive the component.

2. The sensor according to claim 1, further including a back bias magnet.

3. The sensor according to claim 1, wherein the component includes a capacitor.

4. The sensor according to claim 3, wherein the magnetic sensor includes one or more of a Hall element, an AMR element, and/or a GMR element.

5. The sensor according to claim 1, wherein the molded portion of the IC package has a diameter of less than or equal to 7.6 mm.

6. A method of providing a magnetic field sensor in a molding IC package, comprising:

providing a die with a magnetic sensing element in the die;

providing a leadframe having opposed first and second surfaces, the leadframe supporting the die on the first surface;

providing lead fingers to provide electrical connections to the leadframe and to the die;

a first one of the lead fingers extending from the leadframe in a single piece of material to provide an external lead of the IC package, wherein the die supporting portion of the leadframe is formed from the single piece of material; and

providing a component coupled to the leadframe and coupled to a one of the lead fingers formed from the single piece of material such that the component is an integrated part of the IC package providing the sensor to minimize an air gap between the IC package and an object of interest;

wherein the leadframe includes a downset area at which the component is coupled to the leadframe, and

wherein a thickness of the leadframe in the downset area is less than a thickness of the leadframe in a non-downset area adjacent to the downset area;

wherein the first one of the lead fingers includes the downset area to receive the component.

7. The method according to claim 6, further including providing a back bias magnet for the sensor.

8. The method according to claim 6, wherein the component includes a capacitor.

9. The method according to claim 6, wherein the magnetic sensor includes one or more of a Hall element, an AMR element, and/or a GMR element.