SLUS964D
NOVEMBER 2009 – March 2018
TPS40303
,
TPS40304
,
TPS40305
PRODUCTION DATA.
1
Features
2
Applications
3
Description
Device Images
Simplified Application Diagram
4
Revision History
5
Pin Configuration and Functions
Pin Functions
6
Specifications
6.1
Absolute Maximum Ratings
6.2
ESD Ratings
6.3
Recommended Operating Conditions
6.4
Thermal Information
6.5
Electrical Characteristics
6.6
Typical Characteristics
7
Detailed Description
7.1
Overview
7.2
Functional Block Diagram
7.3
Feature Description
7.3.1
Voltage Reference
7.3.2
Enable Functionality, Start-Up Sequence and Timing
7.3.3
Soft-Start Time
7.3.4
Oscillator and Frequency Spread Spectrum (FSS)
7.3.5
Overcurrent Protection
7.3.6
Drivers
7.3.7
Prebias Start-Up
7.3.8
Power Good
7.3.9
Thermal Shutdown
7.4
Device Functional Modes
7.4.1
Modes of Operation
7.4.1.1
UVLO
7.4.1.2
Disable
7.4.1.3
Calibration
7.4.1.4
Converting
8
Application and Implementation
8.1
Application Information
8.2
Typical Applications
8.2.1
Using the TPS40305 for a 12-V to 1.8-V Point-of-Load Synchronous Buck Regulator
8.2.1.1
Design Requirements
8.2.1.2
Detailed Design Procedure
8.2.1.2.1
Custom Design With WEBENCH® Tools
8.2.1.2.2
Selecting the Switching Frequency
8.2.1.2.3
Inductor Selection (L1)
8.2.1.2.4
Output Capacitor Selection (C12)
8.2.1.2.5
Peak Current Rating of Inductor
8.2.1.2.6
Input Capacitor Selection (C8)
8.2.1.2.7
MOSFET Switch Selection (Q1 and Q2)
8.2.1.2.8
Bootstrap Capacitor (C6)
8.2.1.2.9
VDD Bypass Capacitor (C7)
8.2.1.2.10
BP Bypass Capacitor (C5)
8.2.1.2.11
Short-Circuit Protection (R11)
8.2.1.2.12
Feedback Divider (R4, R5)
8.2.1.2.13
Compensation: (C2, C3, C4, R3, R6)
8.2.1.3
Application Curves
8.2.2
A High-Current, Low-Voltage Design Using the TPS40304
8.2.2.1
Design Requirements
8.2.2.2
Detailed Design Procedure
8.2.2.2.1
Selecting the Switching Frequency
8.2.2.2.2
Inductor Selection (L1)
8.2.2.2.3
Output Capacitor Selection (C12)
8.2.2.2.4
Peak Current Rating of Inductor
8.2.2.2.5
Input Capacitor Selection (C8)
8.2.2.2.6
MOSFET Switch Selection (Q1 and Q2)
8.2.2.2.7
Bootstrap Capacitor (C6)
8.2.2.2.8
VDD Bypass Capacitor (C7)
8.2.2.2.9
BP Bypass Capacitor (C5)
8.2.2.2.10
Short-Circuit Protection (R11)
8.2.2.2.11
Feedback Divider (R4, R5)
8.2.2.2.12
Compensation: (C2, C3, C4, R3, R6)
8.2.2.3
Application Curves
8.2.3
A Synchronous Buck Application Using the TPS40303
8.2.3.1
Design Requirements
8.2.3.2
Detailed Design Procedure
8.2.3.2.1
Selecting the Switching Frequency
8.2.3.2.2
Inductor Selection (L1)
8.2.3.2.3
Output Capacitor Selection (C12)
8.2.3.2.4
Peak Current Rating of Inductor
8.2.3.2.5
Input Capacitor Selection (C8)
8.2.3.2.6
MOSFET Switch Selection (Q1 and Q2)
8.2.3.2.7
Bootstrap Capacitor (C6)
8.2.3.2.8
VDD Bypass Capacitor (C7)
8.2.3.2.9
BP Bypass Capacitor (C5)
8.2.3.2.10
Short-Circuit Protection (R11)
8.2.3.2.11
Feedback Divider (R4, R5)
8.2.3.2.12
Compensation: (C2, C3, C4, R3, R6)
8.2.3.3
Application Curves
9
Power Supply Recommendations
10
Layout
10.1
Layout Guidelines
10.2
Layout Example
11
Device and Documentation Support
11.1
Device Support
11.1.1
Third-Party Products Disclaimer
11.2
Custom Design With WEBENCH® Tools
11.3
Documentation Support
11.3.1
Related Documentation
11.4
Related Links
11.5
Receiving Notification of Documentation Updates
11.6
Community Resources
11.7
Trademarks
11.8
Electrostatic Discharge Caution
11.9
Glossary
12
Mechanical, Packaging, and Orderable Information
6.3
Recommended Operating Conditions
MIN
NOM
MAX
UNIT
VDD
Input voltage
3
20
V
T
J
Operating junction temperature
–40
125
°C