SNOSB22D October   2008  – April 2025 LM5574-Q1

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Pin Configuration and Functions
  6. 5 Specifications
    1. 5.1 Absolute Maximum Ratings
    2. 5.2 ESD Ratings
    3. 5.3 Recommended Operating Conditions
    4. 5.4 Thermal Information
    5. 5.5 Electrical Characteristics
    6. 5.6 Typical Characteristics
  7. 6 Detailed Description
    1. 6.1 Overview
    2. 6.2 Functional Block Diagram
    3. 6.3 Feature Description
      1. 6.3.1 Shutdown and Standby
      2. 6.3.2 Current Limit
      3. 6.3.3 Soft Start
      4. 6.3.4 Thermal Protection
    4. 6.4 Device Functional Modes
      1. 6.4.1 High Voltage Start-Up Regulator
      2. 6.4.2 Oscillator and Sync Capability
      3. 6.4.3 Error Amplifier and PWM Comparator
      4. 6.4.4 Ramp Generator
      5. 6.4.5 Maximum Duty Cycle and Input Dropout Voltage
      6. 6.4.6 Boost Pin
  8. 7 Application and Implementation
    1. 7.1 Application Information
      1. 7.1.1 Bias Power Dissipation Reduction
    2. 7.2 Typical Application
      1. 7.2.1 Design Requirements
      2. 7.2.2 Detailed Design Procedure
        1. 7.2.2.1  Custom Design With WEBENCH® Tools
        2. 7.2.2.2  External Components
        3. 7.2.2.3  R3 (RT)
        4. 7.2.2.4  L1- Inductor
        5. 7.2.2.5  C3- Ramp Capacitor
        6. 7.2.2.6  C9 -Output Capacitor
        7. 7.2.2.7  D1 - Async Diode
        8. 7.2.2.8  C1- Input Capacitor
        9. 7.2.2.9  C8 - Vcc Capacitor
        10. 7.2.2.10 C7 - BST Capacitor
        11. 7.2.2.11 C4 - SS Capacitor
        12. 7.2.2.12 R5, R6 - Feedback Resistor
        13. 7.2.2.13 R1, R2, C2 - SD Pin Components
        14. 7.2.2.14 R4, C5, C6 - Compensation Components
      3. 7.2.3 Application Curves
    3. 7.3 Power Supply Recommendations
    4. 7.4 Layout
      1. 7.4.1 Layout Guidelines
      2. 7.4.2 Layout Example
      3. 7.4.3 Power Dissipation
      4. 7.4.4 Thermal Considerations
  9. 8 Device and Documentation Support
    1. 8.1 Device Support
      1. 8.1.1 Development Support
        1. 8.1.1.1 Custom Design With WEBENCH® Tools
    2. 8.2 Receiving Notification of Documentation Updates
    3. 8.3 Support Resources
    4. 8.4 Trademarks
    5. 8.5 Electrostatic Discharge Caution
    6. 8.6 Glossary
  10. 9 Revision History
  11. 10Mechanical, Packaging, and Orderable Information

7.2.3 Application Curves

The following characteristics apply to the circuit shown in Figure 7-3. These parameters are not tested and represent typical performance only. Unless otherwise stated, the following conditions apply: VIN = 24V, TA = 25°C.

LM5574-Q1 DCM Steady State RippleFigure 7-8 DCM Steady State Ripple
LM5574-Q1 Load RegulationFigure 7-10 Load Regulation
LM5574-Q1 CCM Steady State RippleFigure 7-9 CCM Steady State Ripple
LM5574-Q1 Start-Up OperationFigure 7-11 Start-Up Operation