SNVSAE3B
March 2016 – November 2017
LM5161
PRODUCTION DATA.
1
Features
2
Applications
3
Description
4
Revision History
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
Switching Characteristics
6.7
Typical Characteristics
7
Detailed Description
7.1
Overview
7.2
Functional Block Diagram
7.3
Feature Description
7.3.1
Control Circuit
7.3.2
VCC Regulator
7.3.3
Regulation Comparator
7.3.4
Soft-Start
7.3.5
Error Transconductance (GM) Amplifier
7.3.6
On-Time Generator
7.3.7
Current Limit
7.3.8
N-Channel Buck Switch and Driver
7.3.9
Synchronous Rectifier
7.3.10
Enable / Undervoltage Lockout (EN/UVLO)
7.3.11
Thermal Protection
7.4
Device Functional Modes
7.4.1
Forced Pulse Width Modulation (FPWM) Mode
7.4.2
Undervoltage Detector
8
Applications and Implementation
8.1
Application Information
8.2
Typical Applications
8.2.1
LM5161 Synchronous Buck (15-V to 95-V Input, 12-V Output, 1-A Load)
8.2.1.1
Design Requirements
8.2.1.2
Detailed Design Procedure
8.2.1.2.1
Custom Design With WEBENCH® Tools
8.2.1.2.2
Output Resistor Divider Selection
8.2.1.2.3
Frequency Selection
8.2.1.2.4
Inductor Selection
8.2.1.2.5
Output Capacitor Selection
8.2.1.2.6
Series Ripple Resistor - RESR (FPWM = 1)
8.2.1.2.7
VCC and Bootstrap Capacitor
8.2.1.2.8
Input Capacitor Selection
8.2.1.2.9
Soft-Start Capacitor Selection
8.2.1.2.10
EN/UVLO Resistor Selection
8.2.1.3
Application Curves
8.2.2
LM5161 Isolated Fly-Buck (36-V to 72-V Input, 12-V, 12-W Isolated Output)
8.2.2.1
LM5161 Fly-Buck Design Requirements
8.2.2.2
Detailed Design Procedure
8.2.2.2.1
Selection of VOUT and Turns Ratio
8.2.2.2.2
Secondary Rectifier Diode
8.2.2.2.3
External Ripple Circuit
8.2.2.2.4
Output Capacitor (CVISO)
8.2.2.3
Application Curves
8.2.3
Ripple Configuration
8.3
Do's and Don'ts
9
Power Supply Recommendations
10
Layout
10.1
Layout Guidelines
10.2
Layout Example
11
Device and Documentation Support
11.1
Custom Design With WEBENCH® Tools
11.2
Related Documentation
11.3
Receiving Notification of Documentation Updates
11.4
Community Resources
11.5
Trademarks
11.6
Electrostatic Discharge Caution
11.7
Glossary
12
Mechanical, Packaging, and Orderable Information
Package Options
Mechanical Data (Package|Pins)
PWP|14
MPDS370A
Thermal pad, mechanical data (Package|Pins)
PWP|14
PPTD287A
Orderable Information
snvsae3b_oa
snvsae3b_pm