SNVSC05
December 2021
LM25148
PRODUCTION DATA
1
Features
2
Applications
3
Description
4
Revision History
5
Description (continued)
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
Typical Characteristics
8
Detailed Description
8.1
Overview
8.2
Functional Block Diagram
8.3
Feature Description
8.3.1
Input Voltage Range (VIN)
8.3.2
High-Voltage Bias Supply Regulator (VCC, VCCX, VDDA)
8.3.3
Precision Enable (EN)
8.3.4
Power-Good Monitor (PG)
8.3.5
Switching Frequency (RT)
8.3.6
Dual Random Spread Spectrum (DRSS)
8.3.7
Soft Start
8.3.8
Output Voltage Setpoint (FB)
8.3.9
Minimum Controllable On Time
8.3.10
Error Amplifier and PWM Comparator (FB, EXTCOMP)
8.3.11
Slope Compensation
8.3.12
Inductor Current Sense (ISNS+, VOUT)
8.3.12.1
Shunt Current Sensing
8.3.12.2
Inductor DCR Current Sensing
8.3.13
Hiccup Mode Current Limiting
8.3.14
High-Side and Low-Side Gate Drivers (HO, LO)
8.3.15
Output Configurations (CNFG)
8.3.16
Single-Output Dual-Phase Operation
8.4
Device Functional Modes
8.4.1
Sleep Mode
8.4.2
Pulse Frequency Modulation and Synchronization (PFM/SYNC)
8.4.3
Thermal Shutdown
9
Application and Implementation
9.1
Application Information
9.1.1
Power Train Components
9.1.1.1
Buck Inductor
9.1.1.2
Output Capacitors
9.1.1.3
Input Capacitors
9.1.1.4
Power MOSFETs
9.1.1.5
EMI Filter
9.1.2
Error Amplifier and Compensation
9.2
Typical Applications
9.2.1
Design 1 – High Efficiency 2.1-MHz Synchronous Buck Regulator
9.2.1.1
Design Requirements
9.2.1.2
Detailed Design Procedure
9.2.1.2.1
Custom Design With WEBENCH® Tools
9.2.1.2.2
Custom Design With Excel Quickstart Tool
9.2.1.2.3
Buck Inductor
9.2.1.2.4
Current-Sense Resistance
9.2.1.2.5
Output Capacitors
9.2.1.2.6
Input Capacitors
9.2.1.2.7
Frequency Set Resistor
9.2.1.2.8
Feedback Resistors
9.2.1.2.9
Compensation Components
9.2.1.3
Application Curves
9.2.2
Design 2 – High Efficiency 440-kHz Synchronous Buck Regulator
9.2.2.1
Design Requirements
9.2.2.2
Detailed Design Procedure
9.2.2.3
Application Curves
9.2.3
Design 3 – Dual-Phase 400-kHz 20-A Synchronous Buck Regulator
9.2.3.1
Design Requirements
9.2.3.2
Detailed Design Procedure
9.2.3.3
Application Curves
10
Power Supply Recommendations
11
Layout
11.1
Layout Guidelines
11.1.1
Power Stage Layout
11.1.2
Gate-Drive Layout
11.1.3
PWM Controller Layout
11.1.4
Thermal Design and Layout
11.1.5
Ground Plane Design
11.2
Layout Example
12
Device and Documentation Support
12.1
Device Support
12.1.1
Development Support
12.1.1.1
Custom Design With WEBENCH® Tools
12.2
Documentation Support
12.2.1
Related Documentation
12.2.1.1
PCB Layout Resources
12.2.1.2
Thermal Design Resources
12.3
Receiving Notification of Documentation Updates
12.4
Support Resources
12.5
Trademarks
12.6
Electrostatic Discharge Caution
12.7
Glossary
13
Mechanical, Packaging, and Orderable Information
Package Options
Mechanical Data (Package|Pins)
RGY|24
MPQF143E
Thermal pad, mechanical data (Package|Pins)
RGY|24
QFND678
Orderable Information
snvsc05_oa
snvsc05_pm
1
Features
Functional Safety-Capable
Documentation available to aid functional safety system design
Integrated EMI mitigation
Selectable dual random spread spectrum (DRSS) feature for
enhanced EMI performance
across low and high-frequency bands
Optimized for
CISPR 32 Class B requirements
Versatile synchronous buck DC/DC controller
Wide input voltage range of 3.5 V to
42 V
1% accurate, fixed 3.3-V, 5-V, 12-V, or adjustable output from 0.8 V to
36 V
150°C maximum junction temperature
Lossless DCR or shunt current sensing
Shutdown mode current: 2.3 µA
No-load sleep current: 9.5 µA
Internal 3-ms soft-start ramp
Stackable up to two phases
Advanced dropout with frequency foldback
Internal bootstrap diode
Switching frequency from 100 kHz to 2.2 MHz
SYNC in and SYNC out capability
Selectable PFM or FPWM modes
Inherent protection features for robust design
Internal hiccup mode overcurrent protection
ENABLE and PGOOD functions
VCC, VDDA, and gate-drive UVLO protection
Internal or external loop compensation
Thermal shutdown protection with hysteresis
Create a custom design using the
LM25148 with
WEBENCH®
Power Designer