SNVSC55 September   2025 LM51770-Q1

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Device Comparison
  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
    7. 6.7 Typical Characteristics
  8. 7 Parameter Measurement Information
    1. 7.1 Gate Driver Rise Time and Fall Time
    2. 7.2 Gate Driver Dead (Transition) Time
  9. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1  Power-On Reset (POR System)
      2. 8.3.2  Buck-Boost Control Scheme
        1. 8.3.2.1 Boost Mode
        2. 8.3.2.2 Buck Mode
        3. 8.3.2.3 Buck-Boost Mode
      3. 8.3.3  Power Save Mode
      4. 8.3.4  Supply Voltage Selection – VMAX Switch
      5. 8.3.5  Enable and Undervoltage Lockout
      6. 8.3.6  Oscillator Frequency Selection
      7. 8.3.7  Frequency Synchronization
      8. 8.3.8  Voltage Regulation Loop
      9. 8.3.9  Output Voltage Tracking
      10. 8.3.10 Slope Compensation
      11. 8.3.11 Configurable Soft Start
      12. 8.3.12 Peak Current Sensor
      13. 8.3.13 Current Monitoring and Current Limit Control Loop
      14. 8.3.14 Short Circuit - Hiccup Protection
      15. 8.3.15 nFLT Pin and Protections
      16. 8.3.16 Device Configuration Pin
      17. 8.3.17 Dual Random Spread Spectrum – DRSS
      18. 8.3.18 Gate Driver
    4. 8.4 Device Functional Modes
  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  Slope Compensation
        6. 9.2.2.6  Output Capacitor
        7. 9.2.2.7  Input Capacitor
        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 Output Voltage Frequency Compensation
        13. 9.2.2.13 External Component Selection
      3. 9.2.3 Application Curves
    3. 9.3 System Examples
      1. 9.3.1 Bi-Directional Power Backup
      2. 9.3.2 Parallel (Multiphase) Operation
      3. 9.3.3 External Gate Driver with Logic Level High Side Gate Signals
    4. 9.4 Power Supply Recommendations
    5. 9.5 Layout
      1. 9.5.1 Layout Guidelines
        1. 9.5.1.1 Power Stage Layout
        2. 9.5.1.2 Gate Driver Layout
        3. 9.5.1.3 Controller Layout
      2. 9.5.2 Layout Example
  11. 10Device and Documentation Support
    1. 10.1 Device Support
      1. 10.1.1 Third-Party Products Disclaimer
      2. 10.1.2 Development Support
        1. 10.1.2.1 Custom Design with WEBENCH Tools
    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
    1.     86

Package Options

Refer to the PDF data sheet for device specific package drawings

Mechanical Data (Package|Pins)
  • DCP|38
Thermal pad, mechanical data (Package|Pins)
Orderable Information

9.2.3 Application Curves

LM51770-Q1 Start-up waveform standby to active operation (MODE = V(VCC), Vo = 12 V, Io = 0 A, V(VIN) = 12 V) Figure 9-2 Start-up waveform standby to active operation
(MODE = V(VCC), Vo = 12 V, Io = 0 A, V(VIN) = 12 V)
LM51770-Q1 Inductor current buck-boost operation (MODE = V(VCC), Vo = 12 V, Io = 0 A, V(VIN) = 12 V)Figure 9-4 Inductor current buck-boost operation
(MODE = V(VCC), Vo = 12 V, Io = 0 A, V(VIN) = 12 V)
LM51770-Q1 Inductor current boost operation (MODE = 0 V, Vo = 12 V, Io = 10 mA, V(VIN) = 6 V)Figure 9-6 Inductor current boost operation
(MODE = 0 V, Vo = 12 V, Io = 10 mA, V(VIN) = 6 V)
LM51770-Q1 Inductor current buck operation (MODE = 0 V, Vo = 12 V, Io = 10 mA, V(VIN) = 24 V)Figure 9-8 Inductor current buck operation
(MODE = 0 V, Vo = 12 V, Io = 10 mA, V(VIN) = 24 V)
LM51770-Q1 Efficiency Versus IO (MODE = 0V Vo = 12 V)Figure 9-10 Efficiency Versus IO
(MODE = 0V Vo = 12 V)
LM51770-Q1 Efficiency Versus IO in Boost Mode(VIN = 5 V, Vo = 12 V)Figure 9-12 Efficiency Versus IO in Boost Mode
(VIN = 5 V, Vo = 12 V)
LM51770-Q1 Efficiency Versus IO in Buck ModeVIN = 24 V, Vo = 12 V)Figure 9-14 Efficiency Versus IO in Buck Mode
VIN = 24 V, Vo = 12 V)
LM51770-Q1 Inductor current boost operation (MODE = V(VCC), Vo = 12 V, Io = 0 A, V(VIN) = 6 V)Figure 9-3 Inductor current boost operation
(MODE = V(VCC), Vo = 12 V, Io = 0 A, V(VIN) = 6 V)
LM51770-Q1 Inductor current buck operation (MODE = V(VCC), Vo = 12 V, Io = 0 A, V(VIN) = 24 V)Figure 9-5 Inductor current buck operation
(MODE = V(VCC), Vo = 12 V, Io = 0 A, V(VIN) = 24 V)
LM51770-Q1 Inductor current buck-boost operation (MODE = 0 V, Vo = 12 V, Io = 10 mA, V(VIN) = 12 V)Figure 9-7 Inductor current buck-boost operation
(MODE = 0 V, Vo = 12 V, Io = 10 mA, V(VIN) = 12 V)
LM51770-Q1 Input voltage ramp from 6V to 24V (MODE = V(VCC), Vo = 12 V, Io = 6A Figure 9-9 Input voltage ramp from 6V to 24V
(MODE = V(VCC), Vo = 12 V, Io = 6A
LM51770-Q1 Efficiency Versus IO (MODE = VCC Vo = 12 V)Figure 9-11 Efficiency Versus IO
(MODE = VCC Vo = 12 V)
LM51770-Q1 Efficiency Versus IO in Buck-Boost Mode VIN = 12 V, Vo = 12 V)Figure 9-13 Efficiency Versus IO in Buck-Boost Mode
VIN = 12 V, Vo = 12 V)
LM51770-Q1 Efficiency Versus VIN (Vo = 24 V, IO = 5 A)Figure 9-15 Efficiency Versus VIN
(Vo = 24 V, IO = 5 A)