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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 Powe
r
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