SNVS496F January   2007  – May 2021 LM5002

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
  6. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 High Voltage VCC Regulator
      2. 7.3.2 Oscillator
      3. 7.3.3 External Synchronization
      4. 7.3.4 Enable and Standby
      5. 7.3.5 Error Amplifier and PWM Comparator
      6. 7.3.6 Current Amplifier and Slope Compensation
      7. 7.3.7 Power MOSFET
    4. 7.4 Device Functional Modes
      1. 7.4.1 Thermal Protection
  8. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 VIN
      2. 8.1.2 SW PIN
      3. 8.1.3 EN or UVLO Voltage Divider Selection
      4. 8.1.4 Soft Start
    2. 8.2 Typical Applications
      1. 8.2.1 Non-Isolated Flyback Regulator
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
          1. 8.2.1.2.1 Switching Frequency
          2. 8.2.1.2.2 Flyback Transformer
          3. 8.2.1.2.3 Peak MOSFET Current
          4. 8.2.1.2.4 Output Capacitance
          5. 8.2.1.2.5 Output Diode Rating
          6. 8.2.1.2.6 Power Stage Analysis
          7. 8.2.1.2.7 Loop Compensation
      2. 8.2.2 Isolated Flyback Regulator
        1. 8.2.2.1 Design Requirements
      3. 8.2.3 Boost Regulator
        1. 8.2.3.1 Design Requirements
      4. 8.2.4 24-V SEPIC Regulator
        1. 8.2.4.1 Design Requirements
      5. 8.2.5 12-V Automotive SEPIC Regulator
        1. 8.2.5.1 Design Requirements
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Receiving Notification of Documentation Updates
    2. 11.2 Support Resources
    3. 11.3 Trademarks
    4. 11.4 Electrostatic Discharge Caution
    5. 11.5 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

8.2.2.1 Design Requirements

The isolated flyback converter shown in Figure 8-6 uses a 2.5-V voltage reference (LM431) placed on the isolated secondary side for the regulation setpoint. The LM5002 internal error amplifier is disabled by grounding the FB pin. The LM431 controls the current through the opto-coupler LED, which sets the COMP pin voltage. The R4 and C3 network boosts the phase response of the opto-coupler to increase the loop bandwidth. The output is 5 V at 500 mA and the input voltage ranges from 16 V to 42 V. The switching frequency is set to 250 kHz.