SNAS872 December   2024 LMR60410

PRODMIX  

  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 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 Enable and Undervoltage Lockout
      2. 7.3.2 Soft Start and Recovery from Dropout
      3. 7.3.3 Frequency Selection With RT
      4. 7.3.4 MODE/SYNC Pin Control
      5. 7.3.5 Output Voltage Selection
      6. 7.3.6 Current Limit
      7. 7.3.7 Hiccup Mode
      8. 7.3.8 Power-Good Function
      9. 7.3.9 Spread Spectrum
    4. 7.4 Device Functional Modes
      1. 7.4.1 Shutdown
      2. 7.4.2 Active Mode
        1. 7.4.2.1 Continuous Conduction Mode (CCM)
        2. 7.4.2.2 Auto Mode Operation - Light Load Operation
        3. 7.4.2.3 FPWM Operation - Light Load Operation
        4. 7.4.2.4 Minimum On-Time
        5. 7.4.2.5 Dropout
  9. 8 Applications 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 Switching Frequency Selection
        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 Bootstrap Capacitor (CBOOT) Selection
        6. 8.2.2.6 FB Voltage Divider for Adjustable Versions
          1. 8.2.2.6.1 Feedforward Capacitor (CFF) Selection
        7. 8.2.2.7 RPU - PGOOD Pullup Resistor
      3. 8.2.3 Application 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 Plane Considerations
      2. 8.5.2 Layout Example
  10. 9 Device and Documentation Support
    1. 9.1 Documentation Support
      1. 9.1.1 Related Documentation
    2. 9.2 Receiving Notification of Documentation Updates
    3. 9.3 Support Resources
    4. 9.4 Trademarks
    5. 9.5 Electrostatic Discharge Caution
    6. 9.6 Glossary
  11. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information

Package Options

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

7.3.2 Soft Start and Recovery from Dropout

The LMR60410 uses soft start to prevent output voltage overshoots and large inrush currents during start-up. The soft-start time is fixed internally at 6ms (typical). The LMR60410 device operates correctly even if there is a voltage present on the output before activation.

To start-up the LMR60410 and initiate the soft-start sequence, the voltage applied to the VIN and EN pins must exceed VINUVLO(R) and VEN-TH(R) respectively. After these conditions are met, the soft-start sequence initiates and the output voltage reaches the set-point in 6ms (typical).

Dropout occurs when the input voltage falls below the voltage level of the output voltage setpoint. During this condition, the output voltage tracks the input voltage. After the input voltage increases, the output voltage increases with the same slope as during soft start.

LMR60410 Enable Soft Start Figure 7-2 Enable Soft Start