SNVSAX8
April 2018
LM3478Q-Q1
PRODUCTION DATA.
1
Features
2
Applications
3
Description
Device Images
Typical High Efficiency Step-Up (Boost) Converter
4
Revision History
5
Pin Configuration and Functions
Pin Functions
6
Specifications
6.1
Absolute Maximum Ratings
6.2
ESD Ratings - LM3478Q-Q1
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
Overvoltage Protection
7.3.2
Slope Compensation Ramp
7.3.3
Frequency Adjust/Shutdown
7.3.4
Short-Circuit Protection
7.4
Device Functional Modes
8
Application and Implementation
8.1
Application Information
8.2
Typical Applications
8.2.1
Typical High Efficiency Step-Up (Boost) Converter
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
Power Inductor Selection
8.2.1.2.3
Programming the Output Voltage
8.2.1.2.4
Setting the Current Limit
8.2.1.2.5
Current Limit with External Slope Compensation
8.2.1.2.6
Power Diode Selection
8.2.1.2.7
Power MOSFET Selection
8.2.1.2.8
Input Capacitor Selection
8.2.1.2.9
Output Capacitor Selection
8.2.1.2.10
Compensation
8.2.1.3
Application Curves
8.2.2
Typical SEPIC Converter
8.2.2.1
Design Requirements
8.2.2.2
Detailed Design Procedure
8.2.2.2.1
Power MOSFET Selection
8.2.2.2.2
Power Diode Selection
8.2.2.2.3
Selection of Inductors L1 and L2
8.2.2.2.4
Sense Resistor Selection
8.2.2.2.5
Sepic Capacitor Selection
8.2.2.2.6
Input Capacitor Selection
8.2.2.2.7
Output Capacitor Selection
8.2.2.3
Application Curves
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
Receiving Notification of Documentation Updates
11.3
Documentation Support
11.3.1
Related Documentation
11.4
Trademarks
11.5
Electrostatic Discharge Caution
11.6
Glossary
12
Mechanical, Packaging, and Orderable Information
Package Options
Mechanical Data (Package|Pins)
DGK|8
MPDS028E
Thermal pad, mechanical data (Package|Pins)
Orderable Information
snvsax8_oa
snvsax8_pm
8.2.2.3
Application Curves
Figure 35.
Efficiency vs Load Current (3.3-V In and 12-V Out)
Figure 36.
Efficiency vs Load Current (5-V In and 12-V Out)