Texas Instruments TPS40003 - Manual (Page 4)

SLUU130A – September 2002 – Revised February 2003
4 TPS40003-Based 5-A Converter in Less Than One Square Inch
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
3.3 V 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:
D
V
IN
= 3.0 V to 3.6 V
D
V
OUT
= 1.2 V
±
3%
D
0 A
≤
I
OUT
≤
5 A
D
Efficiency > 90% with a load of 2 A
D
Output voltage ripple < 2% V
OUT
D
Physical size < 1 square inch circuit area