SNVSCO0 January   2024 LM63635C-Q1

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Device Comparison Table
  6. 5 Pin Configuration and Functions
  7. 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 Timing Characteristics
    7. 6.7 Switching Characteristics
    8. 6.8 System Characteristics
    9. 6.9 Typical Characteristics
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Output Voltage Selection
      2. 7.3.2 Switching Frequency Selection
        1. 7.3.2.1 Spread Spectrum Option
      3. 7.3.3 Enable and Start-Up
      4. 7.3.4 RESET Flag Output
      5. 7.3.5 Undervoltage Lockout, Thermal Shutdown, and Output Discharge
    4. 7.4 Device Functional Modes
      1. 7.4.1 Overview
      2. 7.4.2 Light Load Operation
      3. 7.4.3 Dropout Operation
      4. 7.4.4 Minimum On-Time Operation
      5. 7.4.5 Current Limit and Short-Circuit Operation
  9. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 Choosing the Switching Frequency
        2. 8.2.2.2 Inductor Selection
        3. 8.2.2.3 Output Capacitor Selection
        4. 8.2.2.4 Input Capacitor Selection
        5. 8.2.2.5 CBOOT
        6. 8.2.2.6 VCC
        7. 8.2.2.7 External UVLO
        8. 8.2.2.8 Maximum Ambient Temperature
      3. 8.2.3 Application Curves
      4. 8.2.4 EMI Performance Curves
    3. 8.3 Best Design Practices
    4. 8.4 Power Supply Recommendations
    5. 8.5 Layout
      1. 8.5.1 Layout Guidelines
        1. 8.5.1.1 Ground and Thermal Considerations
      2. 8.5.2 Layout Example
  10. 9 Device and Documentation Support
    1. 9.1 Device Support
      1. 9.1.1 Device Nomenclature
    2. 9.2 Documentation Support
      1. 9.2.1 Related Documentation
    3. 9.3 Receiving Notification of Documentation Updates
    4. 9.4 Support Resources
    5. 9.5 Trademarks
    6. 9.6 Glossary
    7. 9.7 Electrostatic Discharge Caution
  11. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information

Package Options

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

8.2.2.7 External UVLO

In some cases, an input UVLO level different than that provided internal to the device is needed. This need can be accomplished by using the circuit shown in Figure 8-2. The input voltage at which the device turns on is designated as VON while the turnoff voltage is VOFF. First, a value for RENB is chosen in the range of 10kΩ to 100kΩ. Then, use Equation 9 to calculate RENT and VOFF.

GUID-DD9385A3-20AF-4FB0-BDB7-D4012849758D-low.gifFigure 8-2 Setup for External UVLO Application
Equation 9. R E N T = R E N B × V O N V E N - H - 1 V O F F = V E n - l × V O N V E N - H

where

  • VON = VIN turn-on voltage
  • VOFF = VIN turn-off voltage