Cantilevered leadframe support structure for magnetic wireless transfer between integrated circuit dies

• US 10,643,929 B2
• Filed: 05/12/2014
• Issued: 05/05/2020
• 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
• Primary Examiner(s): Gauthier, Steven B
• Application Number:
  US14/275,762
• Publication Number:
  US 20150325501A1
• Time in Patent Office: 2,185 Days
• 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. An integrated circuit package comprising:

a first die attach pad and a second die attach pad, the first die attach pad including a first set of cantilevered fingers and the second die attach pad including a second set of cantilevered fingers, each of the first set of cantilevered fingers terminating at a first distal end and each of the second set of cantilevered fingers terminating at a second distal end;

a first die on the first die attach pad, the first die including a first portion on the first distal end, the first die including at least one coil; and

a second die on the second die attach pad, the second die including a second portion on the second distal end, the second die including at least one coil;

wherein each of the first set of cantilevered fingers and each of the second set of cantilevered fingers include five fingers, wherein the distal ends of two sets of fingers are opposite to each other, and one finger extends in a space between the distal ends of two sets of fingers, wherein a distal end of the one finger is adjacent to an edge along a length of the first die or the second die respectively.

2. The integrated circuit package of claim 1, wherein the one finger extends in a direction generally perpendicular to the distal ends of two sets of fingers.

3. The integrated circuit package of claim 1, wherein the first die attach pad and the second die attach pad are cantilevered die attach pads.

4. The integrated circuit package of claim 1, wherein each of the first set of cantilevered fingers is connected to each other within the first die attach pad and each of the second set of cantilevered fingers is connected to each other within the second die attach pad.

5. The integrated circuit package of claim 1, wherein the integrated circuit package functions as a digital isolator.

6. The integrated circuit package of claim 1, wherein an isolation voltage between the first die and the second die is more than 1.5 kV.

7. The integrated circuit package of claim 1, wherein the at least one coil is oriented parallel to a plane of a surface along a length of the first die or the second die.

8. The integrated circuit package of claim 1, wherein the first die and the second die are coplanar.

9. The integrated circuit package of claim 1, wherein the first die attach pad and the second die attach pad are coplanar.

10. The integrated circuit package of claim 1, wherein the first die attach pad and the second die attach pad are separated by at least 0.5 mm.

11. The integrated circuit package of claim 1 further comprising molding compound covering portions of the first die attach pad, the second die attach pad, the first die, and the second die.

12. The integrated circuit package of claim 1 further comprising:

a plurality of bond pads associated with a plurality of lead lines; and

a plurality of wirebonds, each coupled to the plurality of bond pads and the first die or the second die respectively.

13. The integrated circuit package of claim 1, wherein the at least one coil includes an inductive coupling coil.