SNVSCU7B July   2025  – November 2026 LM65440-Q1 , LM65460-Q1

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Device Comparison Table
  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 Typical Characteristics
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Descriptions
      1. 7.3.1  Output Voltage Selection
      2. 7.3.2  EN Pin and Use as VIN UVLO
      3. 7.3.3  Mode Selection
        1. 7.3.3.1 MODE/SYNC Pin Uses for Synchronization
        2. 7.3.3.2 Clock Locking
      4. 7.3.4  Adjustable Switching Frequency
      5. 7.3.5  Dual Phase Operation
      6. 7.3.6  Dual Randrom Spread Spectrum (DRSS)
      7. 7.3.7  Internal LDO, VCC UVLO, and BIAS Input
      8. 7.3.8  Bootstrap Voltage (BST Pin)
      9. 7.3.9  Soft Start and Recovery From Dropout
      10. 7.3.10 Safety Features
        1. 7.3.10.1 Power-Good Monitor
        2. 7.3.10.2 Overcurrent and Short-Circuit Protection
        3. 7.3.10.3 Hiccup
        4. 7.3.10.4 Thermal Shutdown
    4. 7.4 Device Functional Modes
      1. 7.4.1 Shutdown Mode
      2. 7.4.2 Active Mode
        1. 7.4.2.1 Peak Current Mode Operation
        2. 7.4.2.2 Auto Mode Operation
          1. 7.4.2.2.1 Diode Emulation
        3. 7.4.2.3 FPWM Mode Operation
        4. 7.4.2.4 Dropout
        5. 7.4.2.5 Recovery from Dropout
  9. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 Custom Design With WEBENCH® Tools
        2. 8.2.2.2 Choosing the Switching Frequency
        3. 8.2.2.3 FB for Adjustable or Fixed Output Voltage Mode
        4. 8.2.2.4 Inductor Selection
        5. 8.2.2.5 Output Capacitor Selection
        6. 8.2.2.6 Input Capacitor Selection
        7. 8.2.2.7 CBOOT
        8. 8.2.2.8 External UVLO
        9. 8.2.2.9 Maximum Ambient Temperature
      3. 8.2.3 Application Curves
    3. 8.3 Best Design Practices
    4. 8.4 Power Supply Recommendations
    5. 8.5 Layout
      1. 8.5.1 Layout Guidelines
        1. 8.5.1.1 Ground and Thermal Considerations
      2. 8.5.2 Layout Example
  10. 9 Device and Documentation Support
    1. 9.1 Device Support
      1. 9.1.1 Third-Party Products Disclaimer
      2. 9.1.2 Development Support
        1. 9.1.2.1 Custom Design With WEBENCH® Tools
    2. 9.2 Documentation Support
      1. 9.2.1 Related Documentation
    3. 9.3 Receiving Notification of Documentation Updates
    4. 9.4 Support Resources
    5. 9.5 Trademarks
    6. 9.6 Electrostatic Discharge Caution
    7. 9.7 Glossary
  11. 10Revision History
  12. 11Mechanical, Packaging, and Orderable Information

7.3.5 Dual Phase Operation

The LM654x0M-Q1 is capable of dual-phase operation for high-current applications (devices with M in the part number). For dual phase designs, simply connect RT and the COMP pins as shown in Figure 7-6 or Figure 7-7. The primary device is recognized by tying a resistor to ground on the RT pin as shown in Table 7-4. Note that the value of this resistor is not the same as calculated with Equation 4. For dual phase operation, only 400kHz or 2.1MHz can be selected. The RT pin of the secondary device must to be configured as shown in Table 7-4 to the same frequency as the primary. The primary device sends a clock signal 180º out of phase to the secondary device from the RT/SYNCOUT pin to the MODE/SYNC pin. The COMP pins of the primary and secondary are tied together and to the loop compensation network (Rc, Cc, Chf). To configure the output voltage for values other than 5V or 3.3V, consult the factory.

Table 7-4 Switching Frequency Configuration
DEVICE RT FSW
Primary 50kΩ to GND 2100kHz
Primary 150kΩ to GND 400kHz
Secondary RT to GND 2100kHz
Secondary RT to VCC 400kHz
LM65440-Q1 LM65460-Q1 LM65480-Q1 Typical Fixed 3.3V Vout 400kHz Dual Phase Schematic Figure 7-6 Typical Fixed 3.3V Vout 400kHz Dual Phase Schematic
LM65440-Q1 LM65460-Q1 LM65480-Q1 Typical Fixed 5V Vout 2100kHz Dual Phase Schematic Figure 7-7 Typical Fixed 5V Vout 2100kHz Dual Phase Schematic