SNVSD17 April   2026 LM5192-Q1

ADVANCE INFORMATION  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Related Products
  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 Requirements for the Serial Control Bus
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1  Input Voltage Range (VIN)
      2. 7.3.2  High-Voltage Bias Supply Regulators (VCC, VDDA)
      3. 7.3.3  Enable (EN)
      4. 7.3.4  Switching Frequency
      5. 7.3.5  Dual Random Spread Spectrum (DRSS)
      6. 7.3.6  Soft Start
      7. 7.3.7  Output Voltage
      8. 7.3.8  Minimum Controllable On-Time
      9. 7.3.9  Dual Loop Architecture
        1. 7.3.9.1 Voltage Loop Error Amplifier
        2. 7.3.9.2 Current Loop Error Amplifier
      10. 7.3.10 Programmable ILIM
      11. 7.3.11 IOUT Monitor
      12. 7.3.12 Cable Drop Compensation
      13. 7.3.13 Slope Compensation
      14. 7.3.14 Shunt Current Sensing
      15. 7.3.15 Hiccup Mode Current Limiting
      16. 7.3.16 Device Configuration (CFG)
      17. 7.3.17 Pulse Frequency Modulation (PFM) / Synchronization
      18. 7.3.18 Thermal Shutdown (TSD)
    4. 7.4 Device Functional Modes
      1. 7.4.1 Shutdown Mode
      2. 7.4.2 Standby Mode
      3. 7.4.3 Ready Mode
      4. 7.4.4 Active Mode
      5. 7.4.5 Sleep Mode
  9. 8 LM5192-Q1 Registers
  10. 9 Application and Implementation
    1. 9.1 Application Information
      1. 9.1.1 Powertrain Components
        1. 9.1.1.1 Buck Inductor
        2. 9.1.1.2 Output Capacitors
        3. 9.1.1.3 Input Capacitors
        4. 9.1.1.4 Power MOSFETs
        5. 9.1.1.5 EMI Filter
      2. 9.1.2 Error Amplifier and Compensation
    2. 9.2 Typical Application
      1. 9.2.1 High Efficiency, Wide Input, 400kHz, Synchronous Buck Regulator
        1. 9.2.1.1 Design Requirements
        2. 9.2.1.2 Detailed Design Procedure
          1. 9.2.1.2.1 Buck Inductor
          2. 9.2.1.2.2 Current-Sense Resistance
          3. 9.2.1.2.3 Output Capacitors
          4. 9.2.1.2.4 Input Capacitors
          5. 9.2.1.2.5 Compensation Components
        3. 9.2.1.3 Application Curves
    3. 9.3 Power Supply Recommendations
    4. 9.4 Layout
      1. 9.4.1 Layout Guidelines
        1. 9.4.1.1 Power Stage Layout
        2. 9.4.1.2 Gate-Drive Layout
        3. 9.4.1.3 PWM Controller Layout
        4. 9.4.1.4 Thermal Design and Layout
        5. 9.4.1.5 Ground Plane Design
      2. 9.4.2 Layout Example
  11. 10Device and Documentation Support
    1. 10.1 Device Support
      1. 10.1.1 Development Support
    2. 10.2 Documentation Support
      1. 10.2.1 Related Documentation
        1. 10.2.1.1 PCB Layout Resources
        2. 10.2.1.2 Thermal Design Resources
    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
  12. 11Revision History
  13. 12Mechanical, Packaging, and Orderable Information
    1. 12.1 Tape and Reel Information

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7.3.17 Pulse Frequency Modulation (PFM) / Synchronization

The LM5192-Q1 provides a diode emulation feature that can be enabled to prevent reverse (drain-to-source) current flow in the low-side MOSFET. When configured for diode emulation (DEM), the low-side MOSFET is switched off when reverse current flow is detected by sensing of the SW voltage using a zero-cross comparator. The benefit of this configuration is lower power loss during light load operation. Note configuring the device for DEM has an effect of slower response to load transients during light load operation.

The diode emulation feature is configured with the PFM / SYNC pin. To enable diode emulation and achieve discontinuous conduction mode (DCM) operation at light loads, connect PFM / SYNC to VDDA. If forced pulse-width modulation (FPWM) or continuous conduction mode (CCM) operation is desired, tie PFM / SYNC to AGND. Note that diode emulation is automatically engaged to prevent reverse current flow during a prebias start-up in PFM. During start-up, when the output voltage approaches the regulation set point a gradual change from DCM to CCM occurs, preventing the output voltage overshoot.

To synchronize the LM5192-Q1 to an external source, apply a logic-level clock (greater than 2V) to the PFM / SYNC pin. The LM5192-Q1 can be synchronized to ±20% of the programmed frequency up to a maximum of 2.2MHz. Under low VIN conditions when the minimum off-time is reached, the synchronization signal is ignored, allowing the switching frequency to be reduced to maintain output voltage regulation.