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Texas Instruments TPS40003 STARTUP WAVEFORM 1 V/div 500 mV/div 500 mV/div t - Time - 200 ∝ s/div

Models: TPS40003

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STARTUP WAVEFORM

SLUU130A – September 2002 – Revised February 2003

Figure 9 shows the startup waveforms with an input voltage of 3.3 V and a load of 0.3 Ω . Note that the output is held low until VSS (pin 4) goes above 0.12 V, and then the output comes up smoothly under closed loop softstart control.

STARTUP WAVEFORM

1V/div 500 mV/div

500 mV/div

t – Time – 200 ∝ s/div

Figure 9.

Figure 10 shows the transient response for a fast load step from 1 A to 2 A.

TRANSIENT RESPONSE

50 mV/div

t – Time – 20 ∝ s/div

Figure 10.

14TPS40003-Based 5-A Converter in Less Than One Square Inch

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Texas Instruments TPS40003 manual STARTUP WAVEFORM 1 V/div 500 mV/div 500 mV/div t - Time - 200 ∝ s/div

Contents

User’s Guide User’s GuideTPS40003 Based 5-A Converter in Less Than One Square Inch EVM IMPORTANT NOTICE DYNAMIC WARNINGS AND RESTRICTIONS Contents 1 Introduction 2 Features 3 Schematic 4 Design Procedure 2 Features1 Introduction 5 PowerPAD Packaging 6 Test Results/Performance Data 7 PCB LayoutSLUU130A - September 2002 - Revised February 3 SchematicFigure 1. Application Diagram for the TPS40002/3 TPS40003-Based 5-A Converter in Less Than One Square Inch4.2 Inductance Value 4 Design Procedure4.1 TPS4000X Family Device Selection 4.3 Input Capacitor Selection4.6 Short Circuit Protection 4.4 Output Capacitor Selection4.5 MOSFET Selection 2 p R 4.7 Compensation Design2 p R4 R54.8 Snubber Component Selection 100005 PowerPAD Packaging Figure 3. PowerPAD PCB Layout GuidelinesSLUU130A - September 2002 - Revised February 6 Test Results/Performance DataThe test setup is shown in figure TPS40003-Based 5-A Converter in Less Than One Square InchTypical efficiency curves are shown in Figure 5 for an input of 3.3 SHORT CIRCUIT OPERATION 2 V/div t - Time - 1 ms/div OUTPUT VOLTAGE RIPPLE 10 mV/div t - Time - 500 ns/divSTARTUP WAVEFORM 1 V/div 500 mV/div 500 mV/div t - Time - 200 ∝ s/div TRANSIENT RESPONSE 50 mV/div t - Time - 20 ∝ s/divTPS40003-Based 5-A Converter in Less Than One Square Inch 7 PCB LayoutSLUU130A - September 2002 - Revised February 16 TPS40003-Based 5-A Converter in Less Than One Square Inch 8 List of MaterialSLUU130A - September 2002 - Revised February ReferenceIMPORTANT NOTICE