SNVSC78B
february 2022 – may 2023
LMQ66410
,
LMQ66420
,
LMQ66430
PRODUCTION DATA
1
1
Features
2
Applications
3
Description
4
Revision History
5
Device Comparison Table
6
Pin Configuration and Functions
7
Specifications
7.1
Absolute Maximum Ratings
7.2
ESD Ratings
7.3
Recommended Operating Conditions
7.4
Thermal Information
7.5
Electrical Characteristics
7.6
System Characteristics
7.7
Typical Characteristics
8
Detailed Description
8.1
Overview
8.2
Functional Block Diagram
8.3
Feature Description
8.3.1
Enable, Start-Up, and Shutdown
8.3.2
Adjustable Switching Frequency (with RT)
8.3.3
Power-Good Output Operation
8.3.4
Internal LDO, VCC, and VOUT/FB Input
8.3.5
Bootstrap Voltage and VBOOT-UVLO (BOOT Terminal)
8.3.6
Output Voltage Selection
8.3.7
Spread Spectrum
8.3.8
Soft Start and Recovery from Dropout
8.3.8.1
Recovery from Dropout
8.3.9
Current Limit and Short Circuit
8.3.10
Thermal Shutdown
8.3.11
Input Supply Current
8.4
Device Functional Modes
8.4.1
Shutdown Mode
8.4.2
Standby Mode
8.4.3
Active Mode
8.4.3.1
CCM Mode
8.4.3.2
Auto Mode – Light Load Operation
8.4.3.2.1
Diode Emulation
8.4.3.2.2
Frequency Reduction
8.4.3.3
FPWM Mode – Light Load Operation
8.4.3.4
Minimum On-Time (High Input Voltage) Operation
8.4.3.5
Dropout
9
Application and Implementation
9.1
Application Information
9.2
Typical Application
9.2.1
Synchronous Buck Regulator at 400 kHz
9.2.2
Design Requirements
9.2.3
Detailed Design Procedure
9.2.3.1
Choosing the Switching Frequency
9.2.3.2
Setting the Output Voltage
9.2.3.2.1
VOUT / FB for Adjustable Output
9.2.3.3
Inductor Selection
9.2.3.4
Output Capacitor Selection
9.2.3.5
Input Capacitor Selection
9.2.3.6
CBOOT
9.2.3.7
VCC
9.2.3.8
CFF Selection
9.2.3.9
External UVLO
9.2.3.10
Maximum Ambient Temperature
9.2.4
Application Curves
9.3
Best Design Practices
9.4
Power Supply Recommendations
9.5
Layout
9.5.1
Layout Guidelines
9.5.1.1
Ground and Thermal Considerations
9.5.2
Layout Example
10
Device and Documentation Support
10.1
Device Support
10.1.1
Third-Party Products Disclaimer
10.1.2
Device Nomenclature
10.2
Documentation Support
10.2.1
Related Documentation
10.3
Receiving Notification of Documentation Updates
10.4
Support Resources
10.5
Trademarks
10.6
Electrostatic Discharge Caution
10.7
Glossary
11
Mechanical, Packaging, and Orderable Information
Package Options
Mechanical Data (Package|Pins)
RXB|14
MPQF580B
Thermal pad, mechanical data (Package|Pins)
Orderable Information
snvsc78b_oa
snvsc78b_pm
9.5.2
Layout Example
Figure 9-13
Example Layout