Cantilevered Leadframe Support Structure for Magnetic Wireless Transfer Between Integrated Circuit Dies

• US 20150325501A1
• Filed: 05/12/2014
• Published: 11/12/2015
• Est. Priority Date: 05/12/2014
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Sutton, Benjamin Michael, Koduri, Sreenivasan K., Mukherjee, Subhashish
• Granted Patent: US 10,643,929 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 23/49503 characterised by the die pad
• CPC Class Codes: H01L 23/4951 Chip-on-leads or leads-on-chip techniques, i.e. inner lead fingers being used as die pad
• CPC Class Codes: H01L 23/49548 Cross section geometry H01L23/49562 takes precedence
• CPC Class Codes: H01L 23/5227 Inductive arrangements or effects of, or between, wiring layers other inductive arrangements H01L23/645
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00

Abstract

A coupling device provides galvanic isolation using a leadframe that is configured to support two integrated circuit chips in a coplanar manner. Each chip contains an inductive coupling coil. The lead frame includes a set of bond pads for attaching bond wires to couple to the two integrated circuit chips. Two separated die attach pads support the two chips. Each die attach pad is configured to support one of the two integrated circuit chips with a plurality of cantilevered fingers.

Claims

1. A coupling device comprising:

a leadframe configured to support two integrated circuit chips each containing an inductive coupling coil, wherein the lead frame comprises;

two separated die attach pads each of minimized metal density, wherein each die attach pad is configured to support an one of the two integrated circuit chips with a plurality of cantilevered fingers, which minimize the metal density; and

a plurality of bond pads for attaching bond wires to couple to the two integrated circuit chips.

2. The coupling device of claim 1, wherein each die attach pad is configured such that each of the plurality of cantilevered fingers is oriented perpendicular to an adjacent portion of each of the inductive coupling coil when the integrated circuit is mounted on the die attach pad.

3. The coupling device of claim 1, wherein each die attach pad is configured such that a more than half of the plurality of cantilevered fingers is oriented perpendicular to an adjacent portion of each of the inductive coupling coil when the integrated circuit is mounted on the die attach pad.

4. The coupling device of claim 1, wherein each die attach pad is configured such that a more than half of the plurality of cantilevered fingers is oriented non-parallel to an adjacent portion of each of the inductive coupling coil when the integrated circuit is mounted on the die attach pad.

5. The coupling device of claim 1, wherein two or more of the plurality of cantilevered fingers have a wedge shaped portion.

6. The coupling device of claim 1, wherein each die attach pad has five fingers.

7. The coupling device of claim 1, wherein the two separated die attach pads are separated by at least 0.5 mm.

8. The coupling device of claim 1, further comprising:

a first integrated circuit mounted on a first one of the die attach pads, the first integrated circuit having first inductive coupling coil wherein at least a majority of the plurality of cantilevered fingers of the first die attach pad are oriented perpendicular to an adjacent portion of the inductive coupling coil; and

a second integrated circuit mounted on a second one of the die attach pads, the second integrated circuit having second inductive coupling coil wherein at least a more than half of the plurality of cantilevered fingers of the second die attach pad are oriented perpendicular to an adjacent portion of the inductive coupling coil.

9. A coupling device comprising:

a leadframe having two separated die attach pads, wherein each die attach pad is of minimized metal density and has a plurality of cantilevered fingers, which minimize the metal density;

a first integrated circuit mounted on the plurality of cantilevered fingers of a first one of the die attach pads, the first integrated circuit having a first inductive coupling coil; and

a second integrated circuit mounted on the plurality of cantilevered fingers of a second one of the die attach pads, the second integrated circuit having a second inductive coupling coil.

10. The coupling device of claim 9, wherein at least a more than half of the plurality of cantilevered fingers of the first die attach pad is oriented perpendicular to an adjacent portion of the first inductive coupling coil in the first integrated circuit.

11. The coupling device of claim 10 wherein at least a more than half of the plurality of cantilevered fingers of the second die attach pad is oriented perpendicular to an adjacent portion of the second inductive coupling coil in the second integrated circuit.

12. The coupling device of claim 9, wherein each of the plurality of cantilevered fingers of the first die attach pad is oriented perpendicular to an adjacent portion of the first inductive coupling coil in the first integrated circuit.

13. The coupling device of claim 12, wherein each of the plurality of cantilevered fingers of the second die attach pad are oriented perpendicular to an adjacent portion of the second inductive coupling coil in the second integrated circuit.

14. The coupling device of claim 9, wherein two or more of the plurality of cantilevered fingers have a wedge shaped portion.

15. A leadframe comprising:

two separated die attach pads, wherein each die attach pad is of minimized metal density and is configured to support an integrated circuit chip with a plurality of cantilevered fingers, which minimize the metal density; and

a plurality of bond pads each coupled to a lead line.

16. The leadframe of claim 15, wherein each die attach pad has a designated region for a magnetic coupling coil contained within an integrated circuit, and wherein each of the plurality of cantilevered fingers is oriented perpendicular to an adjacent portion of the designated region for the magnetic coupling coil.

17. The leadframe of claim 15, wherein each die attach pad has a designated region for a magnetic coupling coil contained within an integrated circuit, and wherein at least a more than half of the plurality of cantilevered fingers is oriented perpendicular to an adjacent portion of the designated region for the magnetic coupling coil.

18. The leadframe of claim 15, wherein each die attach pad has a designated region for a magnetic coupling coil contained within an integrated circuit, and wherein at least a more than half of the plurality of cantilevered fingers is oriented non-parallel to an adjacent portion of the designated region for the magnetic coupling coil.

19. The leadframe of claim 15, wherein two or more of the plurality of cantilevered fingers have a wedge shaped portion.

20. The leadframe of claim 15 being comprised on a strip with a plurality of identical leadframes.