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
1
Features
AEC-Q100 qualified for automotive applications:
Device temperature grade 1: –40°C to +125°C ambient operating temperature
Operation up to 150°C junction temperature
Thermally enhanced package provides exposed top and bottom thermal pads and enables dual-side cooling
Functional Safety-Capable
Documentation available to aid functional safety system design
Designed for Low EMI
Symmetrical input voltage pins with > 1mm clearance to ground
Pin selectable spread spectrum option
Pin selectable FPWM or auto mode operation
Enhanced
HotRod™
QFN (25) package with wettable flanks
Switching frequency from 100kHz to 2.2MHz
Meets CISPR 25 class 5 EMI requirements
Single and dual-output features
Wide input voltage range of 3V to 36V
1% accurate fixed 3.3V, 5V or adjustable outputs from 0.8V to 20V
Hiccup-mode overcurrent protection and thermal shutdown protection with hysteresis
Precision ENABLE and PGOOD functions
50ns t
ON(min)
for high V
IN
/ V
OUT
ratio
80ns t
OFF(min)
for low dropout
Versatile dual-output operation
Shutdown mode current: 0.5µA typical
No-load standby current: 9µA typical
Built-in compensation and 3ms soft start
Independent precision ENABLE and PGOOD
Adaptable single-output operation
> 95% efficient for an 8A load, single output, V
IN
=12V, V
OUT
= 5V
External compensation and adjustable soft start
PGOOD, SYNCIN, and SYNCOUT functions
Pin-to-pin Compatible with
LMQ644A2-Q1