SNVSA90
December 2014
LM5021-Q1
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 Operation Conditions
6.4
Thermal Information
6.5
Electrical Characteristics
6.6
Typical Performance Characteristics
7
Detailed Description
7.1
Overview
7.2
Functional Block Diagram
7.3
Feature Description
7.3.1
PWM Comparator and Slope Compensation
7.3.2
Current Limit and Current Sense
7.3.3
Oscillator, Shutdown and Sync Capability
7.3.4
Gate Driver and Max Duty Cycle Limit
7.3.5
Soft-Start
7.3.6
Hiccup Mode Overload Current Limiting
7.3.7
Skip Cycle Operation
7.4
Device Functional Modes
7.4.1
Operation With VIN Below 20 V
7.4.2
Operation in Soft Start
7.4.3
Operation Under Normal Conditions
7.4.4
Operation in Skip Cycle
7.4.5
Operation at Overload
7.4.6
Operation in Hiccup Mode
8
Application and Implementation
8.1
Application Information
8.1.1
Startup Circuit
8.1.2
Relationship Between Input Capacitor CIN and VCC Capacitor CVCC
8.2
Typical Application
8.2.1
Design Requirements
8.2.2
Detailed Design Procedure
8.2.2.1
Primary Bulk Capacitance
8.2.2.2
Transformer
8.2.2.3
Main Switch FET and Output Rectifier
8.2.2.4
Timing Resistor
8.2.2.5
Soft-Start Time
8.2.2.6
Current Sensing Network
8.2.2.6.1
Gate Drive Resistor
8.2.2.6.2
VCC Capacitor
8.2.2.6.3
Startup Circuit
8.2.3
Application Curves
9
Power Supply Recommendations
10
Layout
10.1
Layout Guidelines
10.2
Layout Example
11
Device and Documentation Support
11.1
Trademarks
11.2
Electrostatic Discharge Caution
11.3
Glossary
12
Mechanical, Packaging, and Orderable Information
Package Options
Mechanical Data (Package|Pins)
DGK|8
MPDS028E
Thermal pad, mechanical data (Package|Pins)
Orderable Information
snvsa90_oa
snvsa90_pm
4 Revision History
DATE
REVISION
NOTES
December 2014
*
Initial release.