SLUSFM2
August 2024
LMR51440-Q1
,
LMR51450-Q1
PRODUCTION DATA
1
1
Features
2
Applications
3
Description
4
Device Comparison Table
5
Pin Configuration and 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
System Characteristics
6.7
Typical Characteristics
7
Detailed Description
7.1
Overview
7.2
Functional Block Diagram
7.3
Feature Description
7.3.1
Fixed Frequency Peak Current Mode Control
7.3.2
Adjustable Output Voltage
7.3.3
Enable
7.3.4
Switching Frequency
7.3.5
Power-Good Flag Output
7.3.6
Minimum ON-Time, Minimum OFF-Time, and Frequency Foldback
7.3.7
Bootstrap Voltage
7.3.8
Overcurrent and Short-Circuit Protection
7.3.9
Soft Start
7.3.10
Thermal Shutdown
7.4
Device Functional Modes
7.4.1
Shutdown Mode
7.4.2
Active Mode
7.4.3
CCM Mode
7.4.4
Light-Load Operation (PFM Version)
7.4.5
Light-Load Operation (FPWM Version)
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
Output Voltage Set-Point
8.2.2.3
Switching Frequency
8.2.2.4
Inductor Selection
8.2.2.5
Output Capacitor Selection
8.2.2.6
Input Capacitor Selection
8.2.2.7
Bootstrap Capacitor
8.2.2.8
Undervoltage Lockout Setpoint
8.2.3
Application Curves
8.3
Power Supply Recommendations
8.4
Layout
8.4.1
Layout Guidelines
8.4.1.1
Compact Layout for EMI Reduction
8.4.1.2
Feedback Resistors
8.4.2
Layout Example
9
Device and Documentation Support
9.1
Device Support
9.1.1
Development Support
9.1.1.1
Custom Design With WEBENCH® Tools
9.2
Documentation Support
9.2.1
Related Documentation
9.3
Receiving Notification of Documentation Updates
9.4
Support Resources
9.5
Trademarks
9.6
Electrostatic Discharge Caution
9.7
Glossary
10
Revision History
11
Mechanical, Packaging, and Orderable Information
11.1
Tape and Reel Information
4
Device Comparison Table
ORDERABLE PART NUMBER
CURRENT
PFM OR FPWM
SPREAD SPECTRUM
LMR51440SQDRRRQ1
4A
PFM
Yes
LMR51440FSQDRRRQ1
4A
FPWM
Yes
LMR51450SQDRRRQ1
5A
PFM
Yes
LMR51450FSQDRRRQ1
5A
FPWM
Yes