SNVSCT4B April   2025  – October 2026 LM72880-Q1

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Related Products
  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 Timing Requirements for the Serial Control Bus
    7. 6.7 Typical Characteristics
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1  Input Voltage Range (VIN)
      2. 7.3.2  High-Voltage Bias Supply Regulators (VCC, VDDA)
      3. 7.3.3  Enable (EN/UVLO)
      4. 7.3.4  Switching Frequency
      5. 7.3.5  Dual Random Spread Spectrum (DRSS)
      6. 7.3.6  Soft Start
      7. 7.3.7  Output Voltage and Output Voltage Slew Rate
      8. 7.3.8  Minimum Controllable On-Time
      9. 7.3.9  Dual Loop Architecture
        1. 7.3.9.1 Voltage Loop Error Amplifier
        2. 7.3.9.2 Current Loop Error Amplifier
      10. 7.3.10 Programmable OVP
      11. 7.3.11 Programmable ILIM
      12. 7.3.12 IOUT Monitor
      13. 7.3.13 Cable Drop Compensation
      14. 7.3.14 Slope Compensation
      15. 7.3.15 Shunt Current Sensing
      16. 7.3.16 Hiccup Mode Current Limiting
      17. 7.3.17 Device Configuration (CNFG)
      18. 7.3.18 Pulse Frequency Modulation (PFM) / Synchronization
      19. 7.3.19 Out-of-Audio Operation
      20. 7.3.20 Thermal Shutdown (TSD)
    4. 7.4 Device Functional Modes
      1. 7.4.1 Shutdown Mode
      2. 7.4.2 Standby Mode
      3. 7.4.3 Ready Mode
      4. 7.4.4 Active Mode
      5. 7.4.5 Sleep Mode
    5. 7.5 Programming
      1. 7.5.1 I2C Bus Operation
      2. 7.5.2 Clock Stretching
      3. 7.5.3 Data Transfer Formats
      4. 7.5.4 Single READ from a Defined Register Address
      5. 7.5.5 Sequential READ Starting from a Defined Register Address
      6. 7.5.6 Single WRITE to a Defined Register Address
      7. 7.5.7 Sequential WRITE Starting at a Defined Register Address
  9. 8 LM72880-Q1 Registers
  10. 9 Application and Implementation
    1. 9.1 Application Information
      1. 9.1.1 Power Train Components
        1. 9.1.1.1 Buck Inductor
        2. 9.1.1.2 Output Capacitors
        3. 9.1.1.3 Input Capacitors
        4. 9.1.1.4 EMI Filter
      2. 9.1.2 Error Amplifier and Compensation
      3. 9.1.3 Maximum Ambient Temperature
        1. 9.1.3.1 Derating Curves
    2. 9.2 Typical Application
      1. 9.2.1 High Efficiency, Wide Input, 400kHz, Synchronous Buck Regulator
        1. 9.2.1.1 Design Requirements
        2. 9.2.1.2 Detailed Design Procedure
          1. 9.2.1.2.1 Custom Design With WEBENCH® Tools
          2. 9.2.1.2.2 Buck Inductor
          3. 9.2.1.2.3 Current-Sense Resistance
          4. 9.2.1.2.4 Output Capacitors
          5. 9.2.1.2.5 Input Capacitors
          6. 9.2.1.2.6 Compensation Components
        3. 9.2.1.3 Application Curves
    3. 9.3 Power Supply Recommendations
    4. 9.4 Layout
      1. 9.4.1 Layout Guidelines
        1. 9.4.1.1 Thermal Design and Layout
      2. 9.4.2 Layout Example
  11. 10Device and Documentation Support
    1. 10.1 Device Support
      1. 10.1.1 Development Support
        1. 10.1.1.1 Custom Design With WEBENCH® Tools
    2. 10.2 Documentation Support
      1. 10.2.1 Related Documentation
        1. 10.2.1.1 PCB Layout Resources
        2. 10.2.1.2 Thermal Design Resources
    3. 10.3 Receiving Notification of Documentation Updates
    4. 10.4 Support Resources
    5. 10.5 Trademarks
    6. 10.6 Electrostatic Discharge Caution
    7. 10.7 Glossary
  12. 11Revision History
  13. 12Mechanical, Packaging, and Orderable Information

7.3.3 Enable (EN/UVLO)

Connect the enable pin to voltage as high as 80V. If the EN pin is pulled below 0.55V, the LM72880-Q1 is in shutdown mode with an IQ of 4.7μA (typical) current draw from VIN. When the enable voltage is between 0.55V < EN < 1V, the LM72880-Q1 is in standby mode. When in standby mode, the VCC regulator is enabled, default registers and trim bits loaded, the digital block is disabled, the device is not switching, and the IQ current is 310μA (typical). When the enable voltage is above 1V, the LM72880-Q1 is in ready mode after the 100μs (typical) enable to ready delay. When in ready mode, the I2C interface is available, the device is not switching, and the IQ current is 1mA (typical). The LM72880-Q1 starts up and enters active mode, when the CONV_EN bit in the OPERATION register is set.

Users can also enable the LM72880-Q1 with standard CMOS logic drivers. A voltage greater than 2.0V enables the LM72880-Q1, and a voltage less than 0.4V disables the LM72880-Q1. However, many applications benefit from using a resistor divider RUV1 and RUV2 as shown in the following figure to establish a precision UVLO threshold. TI recommends setting the input voltage turn-on threshold at 4.5V or higher when the rise time of the input supply to LM72880-Q1 is significantly slower than soft-start time. TI does not recommend leaving the EN pin floating.

Use Equation 2 to calculate the UVLO resistors given the required input turn-on voltage. The EN voltage hysteresis, VEN-HYS, is 100mV or 10% of the EN voltage rising threshold, VEN-TH, therefore the input turn-off voltage is 90% of the input turn-on voltage.

Equation 2. R UV 1 = V IN ( on ) V EN - TH - 1 × R UV 2