SNVSAR5B December   2016  – March 2018 LMR23625-Q1

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Simplified Schematic
      2.      Efficiency vs Load, VIN = 12 V, PFM Option
  4. 4 Revision History
  5. 5 Device Comparison
  6. 6 Pin Configuration and Functions
    1.     Pin 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 Timing Characteristics
    7. 7.7 Switching Characteristics
    8. 7.8 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  Fixed-Frequency Peak-Current-Mode Control
      2. 8.3.2  Adjustable Output Voltage
      3. 8.3.3  EN/SYNC
      4. 8.3.4  VCC, UVLO
      5. 8.3.5  Minimum ON-Time, Minimum OFF-Time and Frequency Foldback at Dropout Conditions
      6. 8.3.6  Power Good (PGOOD)
      7. 8.3.7  Internal Compensation and CFF
      8. 8.3.8  Bootstrap Voltage (BOOT)
      9. 8.3.9  Overcurrent and Short-Circuit Protection
      10. 8.3.10 Thermal Shutdown
    4. 8.4 Device Functional Modes
      1. 8.4.1 Shutdown Mode
      2. 8.4.2 Active Mode
      3. 8.4.3 CCM Mode
      4. 8.4.4 Light Load Operation (PFM Option)
      5. 8.4.5 Light Load Operation (FPWM Option)
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Applications
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
        1. 9.2.2.1  Custom Design With WEBENCH® Tools
        2. 9.2.2.2  Output Voltage Setpoint
        3. 9.2.2.3  Switching Frequency
        4. 9.2.2.4  Inductor Selection
        5. 9.2.2.5  Output Capacitor Selection
        6. 9.2.2.6  Feed-Forward Capacitor
        7. 9.2.2.7  Input Capacitor Selection
        8. 9.2.2.8  Bootstrap Capacitor Selection
        9. 9.2.2.9  VCC Capacitor Selection
        10. 9.2.2.10 Undervoltage Lockout Setpoint
      3. 9.2.3 Application Curves
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
      1. 11.1.1 Compact Layout for EMI Reduction
      2. 11.1.2 Ground Plane and Thermal Considerations
      3. 11.1.3 Feedback Resistors
    2. 11.2 Layout Examples
  12. 12Device and Documentation Support
    1. 12.1 Device Support
      1. 12.1.1 Development Support
        1. 12.1.1.1 Custom Design With WEBENCH® Tools
    2. 12.2 Receiving Notification of Documentation Updates
    3. 12.3 Community Resources
    4. 12.4 Trademarks
    5. 12.5 Electrostatic Discharge Caution
    6. 12.6 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

Refer to the PDF data sheet for device specific package drawings

Mechanical Data (Package|Pins)
  • DRR|12
  • DDA|8
Thermal pad, mechanical data (Package|Pins)
Orderable Information

8.4.2 Active Mode

The LMR23625-Q1 is in active mode when VEN is above the precision enable threshold, VIN and VCC are above their respective UVLO level. The simplest way to enable the LMR23625-Q1 is to connect the EN pin to VIN pin. This allows self startup when the input voltage is in the operating range: 4 V to 36 V. See VCC, UVLO and EN/SYNC for details on setting these operating levels.

In active mode, depending on the load current, the LMR23625-Q1 is in one of four modes:

  1. Continuous conduction mode (CCM) with fixed switching frequency when load current is above half of the peak-to-peak inductor current ripple (for both PFM and FPWM options).
  2. Discontinuous conduction mode (DCM) with fixed switching frequency when load current is lower than half of the peak-to-peak inductor current ripple in CCM operation (only for PFM option).
  3. Pulse frequency modulation mode (PFM) when switching frequency is decreased at very light load (only for PFM option).
  4. Forced pulse width modulation mode (FPWM) with fixed switching frequency even at light load (only for FPWM option).