Texas Instruments TPS40003 Introduction, Features, Mark Dennis, List of Material, Systems Power

SLUU130A – September 2002 – Revised February 2003

TPS40003-Based 5-A Converter in Less Than One Square Inch

Mark Dennis Systems Power

Contents

1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

2 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

3 Schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

4 Design Procedure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

5 PowerPAD Packaging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

6 Test Results/Performance Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

7 PCB Layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

8 List of Material . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

1 Introduction

The TPS40002 and the TPS40003 are voltage-mode, synchronous buck PWM controllers that utilize TI’s proprietary Predictive Gate Drive technology to wring maximum efficiency from step-down converters. These controllers provide a bootstrap charging circuit to allow the use of an N-channel MOSFET as the topside buck switch to reduce conduction losses and increase silicon device utilization. Predictive Gate Drive technology controls the delay from main switch turn-off to synchronous rectifier turn-on and also the delay from rectifier turn-off to main switch turn-on. This allows minimization of the losses in the MOSFET body diodes by reducing conduction and reverse recovery time. This user’s guide provides details on a 5-A buck converter that converts

3.3V down to a 1.2-V level utilizing the TPS40003 controller, with less than one square inch board area. A schematic for the board is shown in Figure 1. A list of material is provided in the final section.

2 Features

The specification for this board is as follows:

DVIN = 3.0 V to 3.6 V

DVOUT = 1.2 V ± 3%

D0 A ≤ IOUT ≤ 5 A

DEfficiency > 90% with a load of 2 A

DOutput voltage ripple < 2% VOUT

DPhysical size < 1 square inch circuit area

4TPS40003-Based 5-A Converter in Less Than One Square Inch