# US 2010/0167465 A1 · Multiphase synchronous buck converter

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- Number: US 2010/0167465 A1
- Document ID: US20100167465A1
- Status: Published application
- Kind: A1
- Application number: 12/723,128
- Filed: 2010-03-12
- Published: 2010-07-01
- Earliest claimed: 2008-01-28
- Assignees: Fairchild Semiconductor Corporation
- Inventors: Yong Liu; Tiburcio A. Maldo; Hua Yang
- Web page: https://patentgrep.com/patent/US20100167465A1

## CPC

- H10W 70/481: {for devices being provided for in groups H10D8/00 - H10D48/00}
- H10W 70/442: {of multiple leadframes in a single chip}
- H10W 90/811: {Multiple chips on leadframes}
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10

## Abstract

Disclosed in this specification is a multiphase buck converter package and process for forming such package. The package includes at least four dies and at least nine parallel leads. The dies are electrically connected through a plurality of die attach pads, thus eliminating the need for wirebonding.

## Claims

### Claim 1

A process for forming a packaged multiphase buck converter, comprising the steps of:
providing a lead frame comprising a plurality of leads, a first die attach pad, a second die attach pad integral with the first die attach pad, and a third die attach pad, each of which is electrically connected to the others, wherein the first and second pads are in a first plane, the second die attach pad and third die attach pad being connected by a conductive bridge, the third die attach pad having a first lead;
mounting a first die, with a first source, a first gate, and a first drain, to the first die attach pad such that the first drain is electrically connected to the first die attach pad, and thus to the first lead;
mounting a second die, with a second source, a second gate, and a second drain, to the third die attach pad such that the second source is electrically connected to the third die attach pad, and thus to the first lead;
mounting a fourth die attach pad to the second drain, the fourth die attach pad having a second lead;
bending the bridge such that the first and second leads contact the plurality of leads, and disposes the third die attach pad in a second plane parallel, but separated from, the first plane;
mounting a fifth die attach pad, with a third lead to the first source such that the third lead contacts the plurality of leads;
mounting a fourth lead to the first gate, the fourth lead contacting the plurality of leads;
mounting a fifth lead to the second gate, the fifth lead contacting the plurality of leads;
mounting a third die, with a third source, a third gate, and a third drain, to the second die attach pad such that the third drain electrically contacts the first drain through the first and second die attach pad;
mounting a fourth die with a fourth source, a fourth gate, and a fourth drain to a sixth die attach pad with a sixth lead such that the fourth drain contacts the sixth lead;
mounting the sixth die attach pad to the lead frame such that the third source contacts the sixth lead which contacts the plurality of leads;
mounting a seventh lead to the fourth gate, the seventh lead contacting the plurality of leads;
mounting a eighth lead to the third gate, the eighth lead contacting the plurality of leads; and
mounting a seventh die attach pad with a ninth lead to the lead frame such that the fourth source contacts the ninth lead which contacts the plurality of leads.

### Claim 2 (depends on 1)

The process as recited in claim 1, further comprising the step of encasing the buck converter within a molding compound such that a portion of the plurality of leads extends outside of the molding compound.

### Claim 3 (depends on 2)

The process as recited in claim 2, further comprising the step of cutting the lead frame, thus freeing the encased buck converter from the lead frame.

### Claim 4

A process for forming a packaged multiphase buck converter, comprising the steps of:
providing a lead frame comprising a plurality of leads, a first die attach pad, a second die attach pad integral with the first die attach pad, and a third die attach pad, each of which is electrically connected to the others, wherein the first and second pads are in a first plane, the second die attach pad and third die attach pad being connected by a conductive bridge, the third die attach pad having a first lead;
mounting a first die to the first die attach pad;
mounting a second die to the third die attach pad; and
bending the bridge such that the first lead contacts one lead of the plurality of leads, and disposes the third die attach pad in a second plane parallel, but separated from, the first plane.

### Claim 5 (depends on 4)

The process as recited in claim 4, wherein the first die includes a first source, a first gate, and a first drain, the first die being mounted to the first die attach pad such that the first drain is electrically connected to the first die attach pad, and thus to the first lead.

### Claim 6 (depends on 5)

The process as recited in claim 5, wherein the second die includes a second source, a second gate, and a second drain, the second die being mounted to the third die attach pad such that the second source is electrically connected to the third die attach pad, and thus to the first lead.

### Claim 7

A process for forming a packaged multiphase buck converter, comprising the steps of:
providing a lead frame comprising a plurality of leads, a first die attach pad, a second die attach pad integral with the first die attach pad, and a third die attach pad, each of which is electrically connected to the others, wherein the first and second pads are in a first plane, the second die attach pad and third die attach pad being connected by a conductive bridge, the third die attach pad having a first lead; and
bending the bridge such that the first lead contacts one lead of the plurality of leads, and disposes the third die attach pad in a second plane parallel, but separated from, the first plane.