SNVSB53C February   2018  – March 2023 LMZM23600

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Device Comparison
  6. 6 Pin Configuration and Functions
  7. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics
    6. 7.6 System Characteristics
    7. 7.7 Typical Characteristics
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 Control Scheme
      2. 8.3.2 Soft-Start Function
      3. 8.3.3 Enable and External UVLO Function
      4. 8.3.4 Current Limit
      5. 8.3.5 Hiccup Mode
      6. 8.3.6 Power Good (PGOOD) Function
      7. 8.3.7 MODE/SYNC Function
        1. 8.3.7.1 Forced PWM Mode
        2. 8.3.7.2 Auto PFM Mode
        3. 8.3.7.3 Dropout Mode
        4. 8.3.7.4 SYNC Operation
      8. 8.3.8 Thermal Protection
    4. 8.4 Device Functional Modes
      1. 8.4.1 Shutdown
      2. 8.4.2 FPWM Operation
      3. 8.4.3 Auto PFM Mode Operation
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Applications
      1. 9.2.1 Design Requirements
        1. 9.2.1.1 Maximum Input Voltage for VOUT < 2.5 V
      2. 9.2.2 Detailed Design Procedure
        1. 9.2.2.1 Custom Design With WEBENCH® Tools
        2. 9.2.2.2 Input Capacitor Selection
        3. 9.2.2.3 Output Capacitor Selection
        4. 9.2.2.4 Feedback Voltage Divider for Adjustable Output Voltage Versions
        5. 9.2.2.5 RPU - PGOOD Pullup Resistor
        6. 9.2.2.6 VIN Divider and Enable
      3. 9.2.3 Application Curves
        1. 9.2.3.1 VOUT = 5 V
        2. 9.2.3.2 VOUT = 3.3 V
        3. 9.2.3.3 VOUT = 12 V
        4. 9.2.3.4 VOUT = 15 V
        5. 9.2.3.5 VOUT = 2.5 V
        6. 9.2.3.6 VOUT = 1.2 V and VOUT = 1.8 V
        7. 9.2.3.7 VOUT = 5 V and 3.3 V Fixed Output Options
    3. 9.3 Best Design Practices
    4. 9.4 Power Supply Recommendations
      1. 9.4.1 Supply Voltage Range
      2. 9.4.2 Supply Current Capability
      3. 9.4.3 Supply Input Connections
        1. 9.4.3.1 Voltage Drops
        2. 9.4.3.2 Stability
    5. 9.5 Layout
      1. 9.5.1 Layout Guidelines
        1. 9.5.1.1 Thermal Design
      2. 9.5.2 Layout Examples
  10. 10Device and Documentation Support
    1. 10.1 Device Support
      1. 10.1.1 Third-Party Products Disclaimer
      2. 10.1.2 Development Support
        1. 10.1.2.1 Custom Design With WEBENCH® Tools
    2. 10.2 Documentation Support
      1. 10.2.1 Related Documentation
    3. 10.3 Receiving Notification of Documentation Updates
    4. 10.4 Support Resources
    5. 10.5 Trademarks
    6. 10.6 Electrostatic Discharge Caution
    7. 10.7 Glossary
  11. 11Mechanical, Packaging, and Orderable Information
    1. 11.1 Tape and Reel Information

8.3.4 Current Limit

The LMZM23600 devices features two current limits inside the IC. A coarse high side or peak current limit is provided to protect against faults. The high-side current limit limits the duration of the on-period of the high-side power MOSFET during a given clock cycle. A precision cycle-by-cycle valley current limit prevents excessive average output current. A new switching cycle is not initiated until the inductor current drops below the valley current limit.

GUID-4C4DBB2D-1D67-4B7D-B24D-4914C0062DD8-low.gifFigure 8-1 Current Limit Operation During Output Short Circuit

#SNVSAQ44956 shows the response of the LMZM23600 device to a short circuit on the output: The peak current limit prevents excessive peak current while the valley current limit prevents excessive average inductor current. After a small number of cycles, hiccup mode is activated.