SLUSF78A
June 2023 – November 2024
UCC28731-Q1
PRODUCTION DATA
1
1
Features
2
Applications
3
Description
4
Pin Configuration and Functions
Pin Functions
5
Specifications
5.1
Absolute Maximum Ratings
5.2
ESD Ratings
5.3
Recommended Operating Conditions
5.4
Thermal Information
5.5
Electrical Characteristics
5.6
Timing Requirements
5.7
Switching Characteristics
5.8
Typical Characteristics
6
Detailed Description
6.1
Overview
6.2
Functional Block Diagram
6.3
Feature Description
6.3.1
Detailed Pin Description
6.3.1.1
VDD (Device Bias Voltage Supply)
6.3.1.2
GND (Ground)
6.3.1.3
HV (High Voltage Startup)
6.3.1.4
DRV (Gate Drive)
6.3.1.5
CBC (Cable Compensation)
6.3.1.6
VS (Voltage Sense)
6.3.1.7
CS (Current Sense)
6.3.2
Primary-Side Regulation (PSR)
6.3.3
Primary-Side Constant Voltage Regulation
6.3.4
Primary-Side Constant Current Regulation
6.3.5
Valley-Switching and Valley-Skipping
6.3.6
Startup Operation
6.3.7
Fault Protection
6.4
Device Functional Modes
7
Application and Implementation
7.1
Application Information
7.2
Typical Application
7.2.1
Design Requirements
7.2.2
Detailed Design Procedure
7.2.2.1
Input Bulk Capacitance and Minimum Bulk Voltage
7.2.2.2
Transformer Turns Ratio, Inductance, Primary-Peak Current
7.2.2.3
Transformer Parameter Verification
7.2.2.4
Output Capacitance
7.2.2.5
VDD Capacitance, CVDD
7.2.2.6
VS Resistor Divider, Line Compensation, and Cable Compensation
7.2.3
Application Curves
7.3
Do's and Don'ts
7.4
Power Supply Recommendations
7.5
Layout
7.5.1
Layout Guidelines
7.5.2
Layout Example
8
Device and Documentation Support
8.1
Device Support
8.1.1
Device Nomenclature
8.1.1.1
Capacitance Terms in Farads
8.1.1.2
Duty-Cycle Terms
8.1.1.3
Frequency Terms in Hertz
8.1.1.4
Current Terms in Amperes
8.1.1.5
Current and Voltage Scaling Terms
8.1.1.6
Transformer Terms
8.1.1.7
Power Terms in Watts
8.1.1.8
Resistance Terms in Ω
8.1.1.9
Timing Terms in Seconds
8.1.1.10
DC Voltage Terms in Volts
8.1.1.11
AC Voltage Terms in Volts
8.1.1.12
Efficiency Terms
8.2
Documentation Support
8.2.1
Related Documentation
8.3
Receiving Notification of Documentation Updates
8.4
Support Resources
8.5
Trademarks
8.6
Electrostatic Discharge Caution
8.7
Glossary
9
Revision History
10
Mechanical, Packaging, and Orderable Information
1
Features
AEC-Q100 qualified for automotive applications:
Device temperature grade 1: –40⁰C to +125⁰C
Device HBM classification Level 2: ±2kV
Device CDM classification Level C4B: ±750V
Functional Safety-Capable
Documentation available to aid functional safety system design
Enables
zero-power
(< 5mW) standby consumption
Primary-side regulation (PSR) eliminates optical coupler
±5% voltage regulation and current regulation across line and load
700V start-up switch with 30V minimum start-up voltage
83kHz maximum switching frequency enables low stand-by power charger designs
Resonant-ring valley-switching operation for improved overall efficiency
Frequency-dither to ease EMI compliance
Clamped gate-drive output for MOSFET
Over-voltage, low-line, and over-current protection functions
Programmable cable compensation
SOIC-7 package