SNVSCU7 July   2025 LM65460-Q1

ADVMIX  

  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
  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
    1. 11.1 Tape and Reel Information

7.3.5 Dual Phase Operation

The LM654x0-Q1 is capable of dual-phase operation for high-current applications. The dual phase operation can be configured for FPWM or PFM mode or operation by simply configuring the primary device MODE pin as described in the MODE/SYNC section of the data sheet. For dual phase designs, simply connect RT and the COMP pins as shown in the typical application circuits below. The primary device is recognized by tying a resistor to ground on the RT pin where as the secondary device RT is either pulled up to VCC or down to ground. During start-up, the primary device sends a clock signal 180 degrees out of phase to the secondary device. To enable low-IQ operation in dual-phase configuration, both devices can be programmed in PFM mode. The COMP pin is the error signal of the internal transconductance amplifier. Connect the COMP pin of the primary to the COMP pin of the secondary to make sure of a balanced current sharing between the phases. For fixed VOUT options tie FB, BIAS of the primary and secondary as shown below. For adjustable configurations, tie the FB, BIAS signals as shown. Unlike single phase applications, in dual phase configurations, the RT pins have to be configured on the primary and secondary devices as shown in the table. At start-up, the device senses the RT pin and configures to a primary or secondary and enables external compensation mode to externally compensate the loop with an RC.

Table 7-4 Switching Frequency Configuration
DEVICE RT FSW
Primary 33kΩ to GND 2100kHz
Primary 100kΩ to GND 400kHz
Secondary GND 2100kHz
Secondary VCC 400kHz
LM65460-Q1 Typical Fixed 3.3V Vout 400kHz Dual Phase Schematic Figure 7-6 Typical Fixed 3.3V Vout 400kHz Dual Phase Schematic
LM65460-Q1 Typical fixed 5V Vout 2100kHz Dual Phase Schematic Figure 7-7 Typical fixed 5V Vout 2100kHz Dual Phase Schematic