SNVSC22D October   2023  – September 2025 LM51772

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Pin Configuration and Functions
  6. 5 Specifications
    1. 5.1 Absolute Maximum Ratings
    2. 5.2 Handling Ratings
    3. 5.3 Recommended Operating Conditions
    4. 5.4 Thermal Information
    5. 5.5 Electrical Characteristics
    6. 5.6 Timing Requirements
    7. 5.7 Typical Characteristics
  7. 6 Parameter Measurement Information
  8. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1  Buck-Boost Control Scheme
        1. 7.3.1.1 Buck Mode
        2. 7.3.1.2 Boost Mode
        3. 7.3.1.3 Buck-Boost Mode
      2. 7.3.2  Power Save Mode
      3. 7.3.3  Programmable Conduction Mode PCM
      4. 7.3.4  Reference System
        1. 7.3.4.1 VIO LDO and nRST-PIN
      5. 7.3.5  Supply Voltage Selection – VSMART Switch and Selection Logic
      6. 7.3.6  Enable and Undervoltage Lockout
        1. 7.3.6.1 UVLO
        2. 7.3.6.2 VDET Comparator
      7. 7.3.7  Internal VCC Regulators
        1. 7.3.7.1 VCC1 Regulator
        2. 7.3.7.2 VCC2 Regulator
      8. 7.3.8  Error Amplifier and Control
        1. 7.3.8.1 Output Voltage Regulation
        2. 7.3.8.2 Output Voltage Feedback
        3. 7.3.8.3 Voltage Regulation Loop
        4. 7.3.8.4 Dynamic Voltage Scaling
      9. 7.3.9  Output Voltage Discharge
      10. 7.3.10 Peak Current Sensor
      11. 7.3.11 Short Circuit - Hiccup Protection
      12. 7.3.12 Current Monitor/Limiter
        1. 7.3.12.1 Overview
        2. 7.3.12.2 Output Current Limitation
        3. 7.3.12.3 Output Current Monitor
      13. 7.3.13 Oscillator Frequency Selection
      14. 7.3.14 Frequency Synchronization
      15. 7.3.15 Output Voltage Tracking
        1. 7.3.15.1 Analog Voltage Tracking
        2. 7.3.15.2 Digital Voltage Tracking
      16. 7.3.16 Slope Compensation
      17. 7.3.17 Configurable Soft Start
      18. 7.3.18 Drive Pin
      19. 7.3.19 Dual Random Spread Spectrum – DRSS
      20. 7.3.20 Gate Driver
      21. 7.3.21 Cable Drop Compensation (CDC)
      22. 7.3.22 CFG-pin and R2D Interface
      23. 7.3.23 Advanced Monitoring Features
        1. 7.3.23.1  Overview
        2. 7.3.23.2  BUSY
        3. 7.3.23.3  OFF
        4. 7.3.23.4  VOUT
        5. 7.3.23.5  IOUT
        6. 7.3.23.6  INPUT
        7. 7.3.23.7  TEMPERATURE
        8. 7.3.23.8  CML
        9. 7.3.23.9  OTHER
        10. 7.3.23.10 ILIM_OP
        11. 7.3.23.11 nFLT/nINT Pin Output
        12. 7.3.23.12 Status Byte
      24. 7.3.24 Protection Features
        1. 7.3.24.1  Thermal Shutdown (TSD)
        2. 7.3.24.2  Over Current Protection
        3. 7.3.24.3  Output Over Voltage Protection 1 (OVP1)
        4. 7.3.24.4  Output Over Voltage Protection 2 (OVP2)
        5. 7.3.24.5  Input Voltage Protection (IVP)
        6. 7.3.24.6  Input Voltage Regulation (IVR)
        7. 7.3.24.7  Power Good
        8. 7.3.24.8  Boot-Strap Under Voltage Protection
        9. 7.3.24.9  Boot-strap Over Voltage Clamp
        10. 7.3.24.10 CRC - CHECK
    4. 7.4 Device Functional Modes
      1. 7.4.1 Overview
      2. 7.4.2 Logic State Description
    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 LM51772 Registers
  10. 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  Custom Design with WEBENCH Tools
        2. 9.2.2.2  Frequency
        3. 9.2.2.3  Feedback Divider
        4. 9.2.2.4  Inductor and Current Sense Resistor Selection
        5. 9.2.2.5  Output Capacitor
        6. 9.2.2.6  Input Capacitor
        7. 9.2.2.7  Slope Compensation
        8. 9.2.2.8  UVLO Divider
        9. 9.2.2.9  Soft-Start Capacitor
        10. 9.2.2.10 MOSFETs QH1 and QL1
        11. 9.2.2.11 MOSFETs QH2 and QL2
        12. 9.2.2.12 Loop Compensation
        13. 9.2.2.13 External Component Selection
      3. 9.2.3 Application Curves
    3. 9.3 USB-PD Source with Power Path
    4. 9.4 Parallel (Multiphase) Operation
    5. 9.5 Constant Current LED Driver
    6. 9.6 Wireless Charging Supply
    7. 9.7 Bi-Directional Power Backup
    8. 9.8 Power Supply Recommendations
    9. 9.9 Layout
      1. 9.9.1 Layout Guidelines
        1. 9.9.1.1 Power Stage Layout
        2. 9.9.1.2 Gate Driver Layout
        3. 9.9.1.3 Controller Layout
      2. 9.9.2 Layout Example
  11. 10Device and Documentation Support
    1. 10.1 Documentation Support
      1. 10.1.1 Related Documentation
    2. 10.2 Receiving Notification of Documentation Updates
    3. 10.3 Support Resources
    4. 10.4 Trademarks
    5. 10.5 Electrostatic Discharge Caution
    6. 10.6 Glossary
  12. 11Revision History
  13. 12Mechanical, Packaging, and Orderable Information

Package Options

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

5.7 Typical Characteristics

The following conditions apply (unless otherwise noted): TJ = 25°C; V(VCC2) = 5V

LM51772 Switching Frequency Versus RT ResistanceFigure 5-1 Switching Frequency Versus RT Resistance
LM51772 FB Pin Reference Voltage Versus TemperatureFigure 5-3 FB Pin Reference Voltage Versus Temperature
LM51772 Shutdown Current into VIN Versus Pin Voltage VEN/UVLO = 0V ,V(VIN) = 12V, V(BIAS) = 0VFigure 5-5 Shutdown Current into VIN Versus Pin Voltage
VEN/UVLO = 0V ,V(VIN) = 12V, V(BIAS) = 0V
LM51772 Shutdown Current Into BIAS Versus Temperature VEN/UVLO = 0V ,V(VIN) = 3.5V,V(BIAS) = 12VFigure 5-7 Shutdown Current Into BIAS Versus Temperature
VEN/UVLO = 0V ,V(VIN) = 3.5V,V(BIAS) = 12V
LM51772 Quiescent Current Into BIAS Versus BIAS V(BIAS) = 12V , V(VIN) = 3.5V Figure 5-9 Quiescent Current Into BIAS Versus BIAS
V(BIAS) = 12V , V(VIN) = 3.5V
LM51772 VCC2 LDO Output Voltage Versus VCC2 Load Current V(VIN) = 12V, V(BIAS) = 0VFigure 5-11 VCC2 LDO Output Voltage Versus VCC2 Load Current
V(VIN) = 12V, V(BIAS) = 0V
LM51772 VCC2 LDO Output Voltage Versus VIN Voltage V(BIAS) = 0VFigure 5-13 VCC2 LDO Output Voltage Versus VIN Voltage
V(BIAS) = 0V
LM51772 Soft-Start Current Versus Temperature Figure 5-15 Soft-Start Current Versus Temperature
LM51772 Hysteresis Current on EN/UVLO Versus Temperature Figure 5-17 Hysteresis Current on EN/UVLO Versus Temperature
LM51772 Buck Minimum On-time Versus Switching FrequencyFigure 5-19 Buck Minimum On-time Versus Switching Frequency
LM51772 Boost Minimum On-time Versus Switching FrequencyFigure 5-21 Boost Minimum On-time Versus Switching Frequency
LM51772 Gate Driver Transition (Dead) Time Versus Switching Frequency SEL_MIN_DEADTIME_GDRV = 0b01,SEL_SCALE_DT = 0b0, EN_CONST_TDEAD = 0b0Figure 5-23 Gate Driver Transition (Dead) Time Versus Switching Frequency
SEL_MIN_DEADTIME_GDRV = 0b01,SEL_SCALE_DT = 0b0, EN_CONST_TDEAD = 0b0
LM51772 Peak Current Limit Threshold Voltage Versus TemperatureFigure 5-25 Peak Current Limit Threshold Voltage Versus Temperature
LM51772 CSB Input Current Versus Temperature Figure 5-27 CSB Input Current Versus Temperature
LM51772 Average Current Limit Threshold Voltage Versus Temperature ILIM_THRESHOLD = 0x3CFigure 5-29 Average Current Limit Threshold Voltage Versus Temperature
ILIM_THRESHOLD = 0x3C
LM51772 Switching Frequency Versus Temperature R(RT) = 75KΩ Figure 5-2 Switching Frequency Versus Temperature
R(RT) = 75KΩ
LM51772 FB Pin Reference Voltage Versus VO Register DAC-CodeFigure 5-4 FB Pin Reference Voltage Versus VO Register DAC-Code
LM51772 Shutdown Current into VIN Versus Temperature VEN/UVLO = 0V ,V(VIN) = 12V,V(BIAS) = 0VFigure 5-6 Shutdown Current into VIN Versus Temperature
VEN/UVLO = 0V ,V(VIN) = 12V,V(BIAS) = 0V
LM51772 Quiescent Current Into BIAS Versus BIAS Pin Voltage V(VIN) = 3.5V Figure 5-8 Quiescent Current Into BIAS Versus BIAS Pin Voltage
V(VIN) = 3.5V
LM51772 Standby Current into BIAS Versus Temperature V(VIN) = 3.5V V(VIN) = 12V Figure 5-10 Standby Current into BIAS Versus Temperature
V(VIN) = 3.5V V(VIN) = 12V
LM51772 VCC2 LDO Output Voltage Versus VCC2 Load Current V(VIN) = 3.5V, V(BIAS) = 12VFigure 5-12 VCC2 LDO Output Voltage Versus VCC2 Load Current
V(VIN) = 3.5V, V(BIAS) = 12V
LM51772 VCC2 LDO Output Voltage Versus BIAS Voltage V(VIN) = 2.5VFigure 5-14 VCC2 LDO Output Voltage Versus BIAS Voltage
V(VIN) = 2.5V
LM51772 EN/UVLO Threshold Versus Temperature Figure 5-16 EN/UVLO Threshold Versus Temperature
LM51772 Buck Minimum Off-time Versus Switching Frequency Figure 5-18 Buck Minimum Off-time Versus Switching Frequency
LM51772 Boost Minimum Off-time Versus Switching FrequencyFigure 5-20 Boost Minimum Off-time Versus Switching Frequency
LM51772 Buck Minimum Duty-cycle for PSM Operation Versus Switching Frequency (SYNC_OUT = Enabled)Figure 5-22 Buck Minimum Duty-cycle for PSM Operation Versus Switching Frequency (SYNC_OUT = Enabled)
LM51772 Gate Driver Transition (Dead) Time Versus Switching Frequency f(sw) = 100kHz ,SEL_MIN_DEADTIME_GDRV = 0b01, EN_CONST_TDEAD = 0b0, Turn Low-Side off, Turn High-Side onFigure 5-24 Gate Driver Transition (Dead) Time Versus Switching Frequency
f(sw) = 100kHz ,SEL_MIN_DEADTIME_GDRV = 0b01, EN_CONST_TDEAD = 0b0, Turn Low-Side off, Turn High-Side on
LM51772 CSA Input Current Versus TemperatureFigure 5-26 CSA Input Current Versus Temperature
LM51772 Average Current Limit Threshold Voltage Versus Temperature ILIM_THRESHOLD = 0x64Figure 5-28 Average Current Limit Threshold Voltage Versus Temperature
ILIM_THRESHOLD = 0x64
LM51772 Average Current Limit Threshold Voltage Versus Temperature ILIM_THRESHOLD = 0x14Figure 5-30 Average Current Limit Threshold Voltage Versus Temperature
ILIM_THRESHOLD = 0x14