SLVSBF3B
June 2012 – May 2019
TPS54678
PRODUCTION DATA.
1
Features
2
Applications
3
Description
Device Images
Simplified Schematic
Efficiency vs Output Current
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
Fixed Frequency PWM Control
7.3.2
Slope Compensation and Output Current
7.3.3
Bootstrap Voltage (Boot) and Low Dropout Operation
7.3.4
Error Amplifier
7.3.5
Voltage Reference
7.3.6
Adjusting the Output Voltage
7.3.7
Enable and Adjusting Undervoltage Lockout
7.3.8
Soft-Start Pin
7.3.9
Sequencing
7.3.10
Constant Switching Frequency and Timing Resistor (RT/CLK Pin)
7.3.11
Overcurrent Protection
7.3.11.1
High-Side Overcurrent Protection
7.3.11.2
Low-Side Overcurrent Protection
7.3.12
Safe Start-Up into Prebiased Outputs
7.3.13
Synchronize Using the RT/CLK Pin
7.3.14
Power Good (PWRGD Pin)
7.3.15
Overvoltage Transient Protection
7.3.16
Thermal Shutdown
7.4
Device Functional Modes
7.4.1
Small Signal Model for Loop Response
7.4.2
Simple Small Signal Model for Peak Current Mode Control
7.4.3
Small Signal Model for Frequency Compensation
8
Application and Implementation
8.1
Application Information
8.2
Typical Application
8.2.1
Design Requirements
8.2.2
Detailed Design Procedure
8.2.2.1
Custom Design With WEBENCH® Tools
8.2.2.2
Step One: Select the Switching Frequency
8.2.2.3
Step Two: Select the Output Inductor
8.2.2.4
Step Three: Choose the Output Capacitor
8.2.2.5
Step Four: Select the Input Capacitor
8.2.2.6
Step Five: Choose the Soft-Start Capacitor
8.2.2.7
Step Six: Select the Bootstrap Capacitor
8.2.2.8
Step Eight: Select Output Voltage and Feedback Resistors
8.2.2.8.1
Output Voltage Limitations
8.2.2.9
Step Nine: Select Loop Compensation Components
8.2.3
Application Curves
8.2.3.1
Additional Information About Application Curves
8.2.3.1.1
Efficiency
8.2.3.1.2
Voltage Ripple Measurements
8.2.3.1.3
Start-Up and Shutdown Waveforms
8.2.3.1.4
Hiccup Mode Current Limit
9
Power Supply Recommendations
10
Layout
10.1
Layout Guidelines
10.2
Layout Example
10.3
Power Dissipation Estimate
11
Device and Documentation Support
11.1
Device Support
11.1.1
Third-Party Products Disclaimer
11.1.2
Development Support
11.1.2.1
Custom Design With WEBENCH® Tools
11.2
Documentation Support
11.2.1
Related Documentation
11.3
Receiving Notification of Documentation Updates
11.4
Community Resources
11.5
Trademarks
11.6
Electrostatic Discharge Caution
11.7
Glossary
12
Mechanical, Packaging, and Orderable Information
Package Options
Mechanical Data (Package|Pins)
RTE|16
MPQF149D
Thermal pad, mechanical data (Package|Pins)
RTE|16
QFND290G
Orderable Information
slvsbf3b_oa
slvsbf3b_pm
6
Specifications