SLUSCR9 June 2017 UCC28730-Q1


  1. Features
  2. Applications
  3. Description
  4. Revision History
  5. Pin Configuration and Functions
  6. Specifications
    1. 6.1Absolute Maximum Ratings
    2. 6.2ESD Ratings
    3. 6.3Recommended Operating Conditions
    4. 6.4Thermal Information
    5. 6.5Electrical Characteristics
    6. 6.6Timing Requirements
    7. 6.7Switching Characteristics
    8. 6.8Typical Characteristics
  7. Detailed Description
    1. 7.1Overview
    2. 7.2Functional Block Diagram
    3. 7.3Feature Description
      1. 7.3.1Detailed Pin Description
        1. (Device Bias Voltage Supply)
        2. (Ground)
        3. (High Voltage Startup)
        4. (Gate Drive)
        5. (Cable Compensation)
        6. (Voltage Sense)
        7. (Current Sense)
      2. 7.3.2Primary-Side Regulation (PSR)
      3. 7.3.3Primary-Side Constant Voltage Regulation
      4. 7.3.4Primary-Side Constant Current Regulation
      5. 7.3.5Wake-Up Detection and Function
      6. 7.3.6Valley-Switching and Valley-Skipping
      7. 7.3.7Startup Operation
      8. 7.3.8Fault Protection
    4. 7.4Device Functional Modes
  8. Application and Implementation
    1. 8.1Application Information
    2. 8.2Typical Application
      1. 8.2.1Design Requirements
      2. 8.2.2Detailed Design Procedure
        1. Power Estimate
        2. Bulk Capacitance and Minimum Bulk Voltage
        3. Turns Ratio, Inductance, Primary-Peak Current
        4. Parameter Verification
        5. Capacitance
        6. Capacitance, CVDD
        7. Resistor Divider, Line Compensation, and Cable Compensation
        8. Wake-Up Detection
      3. 8.2.3Application Curves
    3. 8.3Do's and Don'ts
  9. Power Supply Recommendations
  10. 10Layout
    1. 10.1Layout Guidelines
    2. 10.2Layout Example
  11. 11Device and Documentation Support
    1. 11.1Device Support
      1. 11.1.1Device Nomenclature
        1. Capacitance Terms in Farads
        2. Duty-Cycle Terms
        3. Frequency Terms in Hertz
        4. Current Terms in Amperes
        5.  Current and Voltage Scaling Terms
        6. Transformer Terms
        7. Power Terms in Watts
        8. Resistance Terms in Ω
        9. Timing Terms in Seconds
        10. Voltage Terms in Volts
        11. Voltage Terms in Volts
        12. Terms
    2. 11.2Documentation Support
      1. 11.2.1Related Documentation
    3. 11.3Receiving Notification of Documentation Updates
    4. 11.4Community Resources
    5. 11.5Trademarks
    6. 11.6Electrostatic Discharge Caution
    7. 11.7Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Orderable Information


  • Qualified for Automotive Applications
  • AEC-Q100 Qualified with the Following Results:
    • Device Temperature Grade 1: -40⁰C to +125⁰C
    • Device HBM Classification Level 2: ±2 kV
    • Device CDM Classification Level C4B: ±750 V
  • Enables Zero-Power (< 5 mW) Standby Consumption
  • Primary-Side Regulation (PSR) Eliminates Opto-coupler
  • ±5% Voltage Regulation and Current Regulation Across Line and Load
  • 700-V Start-up Switch
  • 83-kHz Maximum Switching Frequency Enables Low Stand-by Power Charger Designs
  • Resonant-Ring Valley-Switching Operation for Highest 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


  • Automotive Power Supplies
  • Hybrid and Electric Vehicles in Automotive
  • SMPS for Home Appliances and Industrial Automation
  • Standby and Auxiliary Power Supplies


The UCC28730-Q1 isolated-flyback power supply controller provides Constant-Voltage (CV) and Constant-Current (CC) output regulation without the use of an optical coupler. A minimum switching frequency of 30 Hz facilitates achieving less than 5 mW of no-load power. This device processes information from the primary power switch and an auxiliary flyback winding for precise control of output voltage and current.

An internal 700-V start-up switch, dynamically- controlled operating states and a tailored modulation profile support ultra-low stand-by power without sacrificing start-up time or output transient response. Control algorithms in the UCC28730-Q1 allow operating efficiencies to meet or exceed applicable standards. Discontinuous conduction mode (DCM) operation with valley-switching reduces switching losses. Modulation of the switching frequency and primary current peak amplitude (FM and AM) keeps the conversion efficiency high across the entire load and line ranges.

Device Information(1)

UCC28730-Q1SOIC (7)4.90 mm x 3.90 mm
  1. For all available packages, see the orderable addendum at the end of the data sheet.

Simplified Schematic

UCC28730-Q1 alt_luscr9.gif

Zero-Power Input Consumption at No-Load

UCC28730-Q1 alt2_slusbl6.gif