SNVSBD6C May   2019  – June 2021 LM61440

PRODUCTION DATA  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Device Comparison Table
  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 Timing Characteristics
    7. 7.7 Systems 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  EN/SYNC Uses for Enable and VIN UVLO
      2. 8.3.2  EN/SYNC Pin Uses for Synchronization
      3. 8.3.3  Clock Locking
      4. 8.3.4  Adjustable Switching Frequency
      5. 8.3.5  PGOOD Output Operation
      6. 8.3.6  Internal LDO, VCC UVLO, and BIAS Input
      7. 8.3.7  Bootstrap Voltage and VCBOOT-UVLO (CBOOT Pin)
      8. 8.3.8  Adjustable SW Node Slew Rate
      9. 8.3.9  Spread Spectrum
      10. 8.3.10 Soft Start and Recovery From Dropout
      11. 8.3.11 Output Voltage Setting
      12. 8.3.12 Overcurrent and Short Circuit Protection
      13. 8.3.13 Thermal Shutdown
      14. 8.3.14 Input Supply Current
    4. 8.4 Device Functional Modes
      1. 8.4.1 Shutdown Mode
      2. 8.4.2 Standby Mode
      3. 8.4.3 Active Mode
        1. 8.4.3.1 CCM Mode
        2. 8.4.3.2 Auto Mode - Light Load Operation
          1. 8.4.3.2.1 Diode Emulation
          2. 8.4.3.2.2 Frequency Reduction
        3. 8.4.3.3 FPWM Mode - Light Load Operation
        4. 8.4.3.4 Minimum On-time (High Input Voltage) Operation
        5. 8.4.3.5 Dropout
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
        1. 9.2.2.1  Choosing the Switching Frequency
        2. 9.2.2.2  Setting the Output Voltage
        3. 9.2.2.3  Inductor Selection
        4. 9.2.2.4  Output Capacitor Selection
        5. 9.2.2.5  Input Capacitor Selection
        6. 9.2.2.6  BOOT Capacitor
        7. 9.2.2.7  BOOT Resistor
        8. 9.2.2.8  VCC
        9. 9.2.2.9  BIAS
        10. 9.2.2.10 CFF and RFF Selection
        11. 9.2.2.11 External UVLO
      3. 9.2.3 Application Curves
      4. 9.2.4 USB Type-C System Example
        1. 9.2.4.1 Design Requirements
        2. 9.2.4.2 Detailed Design Procedure
        3. 9.2.4.3 Application Curves
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
      1. 11.1.1 Ground and Thermal Considerations
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Documentation Support
      1. 12.1.1 Related Documentation
    2. 12.2 Receiving Notification of Documentation Updates
    3. 12.3 Support Resources
    4. 12.4 Trademarks
    5. 12.5 Electrostatic Discharge Caution
    6. 12.6 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

3 Description

The LM61440 is a high-performance, DC-DC synchronous step-down converter. With integrated high-side and low-side MOSFETs, up to 4 A of output current is delivered over a wide input range of 3.0 V to 36 V; tolerant of 42 V, easing input surge protection design. The LM61440 implements soft recovery from dropout eliminating overshoot on the output.

The LM61440 is specifically designed for minimal EMI. The device incorporates adjustable SW node rise time, low-EMI VQFN-HR package featuring low switch node ringing, and optimized pinout for ease of use. The switching frequency can be set or synchronized between 200 kHz and 2.2 MHz to avoid noise sensitive frequency bands. In addition the frequency can be selected for improved efficiency at low operating frequency or smaller solution size at high operating frequency.

Auto-mode enables frequency foldback when operating at light loads, allowing an unloaded current consumption of only 7 µA (typical) and high light load efficiency. Seamless transition between PWM and PFM modes, along with very low MOSFET ON resistances and an external bias input, ensures exceptional efficiency across the entire load range.

Electrical characteristics are specified over a junction temperature range of –40°C to +150°C. Find additional resources in the Related Documentation.

Device Information
PART NUMBER PACKAGE(1) BODY SIZE (NOM)
LM61440 VQFN-HR (14) 4.00 mm × 3.50 mm
(1) For all available packages, see the orderable addendum at the end of the data sheet.
GUID-DB38AD2E-9A26-4E82-B21C-37EBF3392519-low.gifSimplified Schematic
GUID-08C76677-5B3E-4DA5-A21A-8094AFAEC977-low.gifEfficiency VOUT = 5 V, FSW = 2200 kHz