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

8.3.7.2 Auto PFM Mode

If the MODE/SYNC terminal is held low the LMZM23600 device enables automatic power-saving-mode transition at light load. With high load the LMZM23600 regulates the output using normal PWM operation. When the load is light, the control logic smoothly transitions to PFM operation and diode emulation. In this mode, the high side MOSFET is turned on for one or more pulses to provide energy to the load. The on-time of the high side in this mode depends on the input voltage level and a pre-programmed internal IPEAK-MIN current level. The higher the input voltage is, the shorter the on-time is. At this point, there is a longer off-time during which the output is still in the regulation window because the load is light, and the output is not getting discharged as quickly. The duration of the off-time depends on the load current level. Lighter load results in longer off-time. This mode of operation results in excellent conversion efficiency at very light load. When auto-PFM mode is used, the output voltage at no load is approximately 1% higher than FPWM operation.