SLUSCA8A
February 2016 – February 2016
UCC28704
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
Typical Characteristics
7
Detailed Description
7.1
Overview
7.2
Functional Block Diagram
7.3
Feature Description
7.3.1
Detailed Pin Description
7.3.1.1
VDD (Device Bias Voltage Supply)
7.3.1.2
GND (Ground)
7.3.1.3
VS (Voltage-Sense)
7.3.1.4
DRV (Gate Drive)
7.3.1.5
CS (Current Sense)
7.3.1.6
NTC/SU (NTC Thermistor Shutdown and External Start Up Control)
7.3.2
Primary-Side Regulation (PSR)
7.3.3
Primary-Side Constant Voltage (CV) Regulation
7.3.4
Primary-Side Constant Current (CC) Regulation
7.3.5
Valley-Switching and Valley-Skipping
7.3.6
Start-Up Operation
7.3.6.1
Initial Power-On with a Start-Up Resistor
7.3.6.2
Initial Power-On with A Depletion-Mode FET
7.3.7
Fault Protection
7.3.8
Constant Current Under-Voltage Protection
7.3.9
Load Transient Response
7.4
Device Functional Modes
8
Applications 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
VDD Capacitance, CDD
8.2.2.2
VDD Start-Up Resistance, RSTR
8.2.2.3
Input Bulk Capacitance and Minimum Bulk Voltage
8.2.2.4
Transformer Turns Ratio, Inductance, Primary-Peak Current
8.2.2.5
Transformer Parameter Verification
8.2.2.6
VS Resistor Divider, Line Compensation, and NTC
8.2.2.7
Standby Power Estimate
8.2.2.8
Output Capacitance
8.2.2.9
Design Considerations in Using with Synchronous Rectifiers
8.2.3
Application Curves
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
Device Support
11.1.1
Device Nomenclature
11.1.1.1
Capacitance Terms in Farads
11.1.1.2
Duty Cycle Terms
11.1.1.3
Frequency Terms in Hertz
11.1.1.4
Current Terms in Amperes
11.1.1.5
Current and Voltage Scaling Terms
11.1.1.6
Transformer Terms
11.1.1.7
Power Terms in Watts
11.1.1.8
Resistance Terms in Ω
11.1.1.9
Timing Terms in Seconds
11.1.1.10
Voltage Terms in Volts
11.1.1.11
AC Voltage Terms in VRMS
11.1.1.12
Efficiency Terms
11.2
Documentation Support
11.2.1
Related Documentation
11.3
Community Resources
11.4
Trademarks
11.5
Electrostatic Discharge Caution
11.6
Glossary
12
Mechanical, Packaging, and Orderable Information
4 Revision History
DATE
REVISION
NOTES
February 2016
A
Initial release.