SNVSAR6B December   2016  – March 2018 LMR23630-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 Product Portfolio
  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 Frequency
      3. 8.3.3  Adjustable Output Voltage
      4. 8.3.4  Enable/Synchronization
      5. 8.3.5  VCC, UVLO
      6. 8.3.6  Minimum ON-time, Minimum OFF-time and Frequency Foldback at Dropout Conditions
      7. 8.3.7  Power Good (PGOOD)
      8. 8.3.8  Internal Compensation and CFF
      9. 8.3.9  Bootstrap Voltage (BOOT)
      10. 8.3.10 Overcurrent and Short-Circuit Protection
      11. 8.3.11 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 UVLO 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 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)
  • DDA|8
  • DRR|12
Thermal pad, mechanical data (Package|Pins)
Orderable Information

8.3.2 Adjustable Frequency

For adjustable switching frequency option of LMR23630-Q1. The switching frequency can be programmed by the impedance RT from the RT pin to ground. The frequency is inversely proportional to the RT resistance. The RT pin can be left floating, and the LMR23630-Q1 will operate at 400-kHz default switching frequency. The RT pin is not designed to be shorted to ground. For a desired requency, typical RT resistance can be found by Equation 1. Table 1 gives typical RT values for a given fSW.

Equation 1. RT(kΩ) = 40200 / fSW(kHz) – 0.6
LMR23630-Q1 Rt_Fs_Curve.pngFigure 14. RT vs Frequency Curve

Table 1. Typical Frequency Setting RT Resistance

fSW (kHz) RT (kΩ)
200 200
350 115
500 78.7
750 53.6
1000 39.2
1500 26.1
2000 19.6
2200 17.8