SNVSCW3
November 2024
LM644A2-Q1
PRODUCTION DATA
1
1
Features
2
Applications
3
Description
4
Device Comparison Table
5
Pin Configuration and Functions
5.1
Wettable Flanks
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
Input Voltage Range (VIN)
7.3.2
Enable EN Pin and Use as VIN UVLO
7.3.3
Output Voltage Selection and Soft Start
7.3.4
SYNC Allows Clock Synchronization and Mode Selection
7.3.5
Clock Locking
7.3.6
Adjustable Switching Frequency
7.3.7
Power-Good Output Voltage Monitoring
7.3.8
Internal LDO, VCC UVLO, and BIAS Input
7.3.9
Bootstrap Voltage and VCBOOT-UVLO (CB1 and CB2 Pin)
7.3.10
CONFIG Device Configuration Pin
7.3.11
Spread Spectrum
7.3.12
Soft Start and Recovery From Dropout
7.3.13
Overcurrent and Short-Circuit Protection
7.3.14
Hiccup
7.3.15
Thermal Shutdown
7.4
Device Functional Modes
7.4.1
Shutdown Mode
7.4.2
Standby Mode
7.4.3
Active Mode
7.4.3.1
Peak Current Mode Operation
7.4.3.2
Auto Mode Operation
7.4.3.2.1
Diode Emulation
7.4.3.3
FPWM Mode Operation
7.4.3.4
Minimum On-time (High Input Voltage) Operation
7.4.3.5
Dropout
7.4.3.6
Recovery from Dropout
7.4.3.7
Other Fault Modes
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
Choosing the Switching Frequency
8.2.2.2
Setting the Output Voltage
8.2.2.3
Inductor Selection
8.2.2.4
Output Capacitor Selection
8.2.2.5
Input Capacitor Selection
8.2.2.6
BOOT Capacitor
8.2.2.7
VCC
8.2.2.8
CFF and RFF Selection
8.2.2.9
SYNCHRONIZATION AND MODE
8.2.2.10
External UVLO
8.2.2.11
Typical Thermal Performance
8.2.3
Application Curves
8.3
Power Supply Recommendations
8.4
Layout
8.4.1
Layout Guidelines
8.4.1.1
Ground and Thermal Considerations
8.4.2
Layout Example
9
Device and Documentation Support
9.1
Device Support
9.1.1
Third-Party Products Disclaimer
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
Package Options
Mechanical Data (Package|Pins)
VBG|24
MPQF795
Thermal pad, mechanical data (Package|Pins)
Orderable Information
snvscw3_oa
snvscw3_pm
6.6
Typical Characteristics
Unless otherwise specified, V
IN
= 13.5V.
Figure 6-1
Feedback Voltage
Figure 6-3
High-side and Low-side Switches R
DS_ON
EN = 0V
Figure 6-2
Shutdown Supply Current
Figure 6-4
High-side and Low-side Current Limits LM644A2