SNVSAI1 June 2017 LM5176


  1. Features
  2. Applications
  3. Description
  4. Simplified Schematic
  5. Revision History
  6. Pin Configuration and Functions
  7. Specifications
    1. 7.1Absolute Maximum Ratings
    2. 7.2ESD Ratings
    3. 7.3Recommended Operating Conditions
    4. 7.4Thermal Information
    5. 7.5Electrical Characteristics
    6. 7.6Typical Characteristics
  8. Detailed Description
    1. 8.1Overview
    2. 8.2Functional Block Diagram
    3. 8.3Feature Description
      1. 8.3.1 Fixed Frequency Valley/Peak Current Mode Control with Slope Compensation
      2. 8.3.2 VCC Regulator and Optional BIAS Input
      3. 8.3.3 Enable/UVLO
      4. 8.3.4 Soft-Start
      5. 8.3.5 Overcurrent Protection
      6. 8.3.6 Average Input/Output Current Limiting
      7. 8.3.7 Operation Above 40-V Input
      8. 8.3.8 CCM Operation
      9. 8.3.9 Frequency and Synchronization (RT/SYNC)
      10. 8.3.10Frequency Dithering
      11. 8.3.11Output Overvoltage Protection (OVP)
      12. 8.3.12Power Good (PGOOD)
      13. 8.3.13Gm Error Amplifier
      14. 8.3.14Integrated Gate Drivers
      15. 8.3.15Thermal Shutdown
    4. 8.4Device Functional Modes
      1. 8.4.1Shutdown, Standby, and Operating Modes
      2. 8.4.2MODE Pin Configuration
  9. Application and Implementation
    1. 9.1Application Information
    2. 9.2Typical Application
      1. 9.2.1Design Requirements
      2. 9.2.2Detailed Design Procedure
        1. Custom Design with WEBENCH Tools
        2. Frequency
        3. VOUT
        4. Inductor Selection
        5. Output Capacitor
        6. Input Capacitor
        7. Sense Resistor (RSENSE)
        8. Slope Compensation
        9. UVLO
        10. Capacitor
        11. Capacitor
        12. QH1 and QL1
        13. QH2 and QL2
        14. Compensation
      3. 9.2.3Application Curves
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1Layout Guidelines
    2. 11.2Layout Example
  12. 12Device and Documentation Support
    1. 12.1Custom Design with WEBENCH Tools
    2. 12.2Documentation Support
      1. 12.2.1Related Documentation
    3. 12.3Receiving Notification of Documentation Updates
    4. 12.4Community Resources
    5. 12.5Trademarks
    6. 12.6Electrostatic Discharge Caution
    7. 12.7Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Orderable Information


  • Single Inductor Buck-Boost Controller for Step-Up/Step-Down DC/DC Conversion
  • Wide VIN: 4.2 V (2.5 V with bias) to 55 V (60 V Maximum)
  • Flexible VOUT: 0.8 V to 55 V
  • VOUT Short Protection
  • High Efficiency Buck-Boost Transition
  • Adjustable Switching Frequency
  • Optional Frequency Sync and Dithering
  • Integrated 2-A MOSFET Gate Drivers
  • Cycle-by-Cycle Current Limit and Optional Hiccup
  • Optional Input or Output Average Current Limiting
  • Programmable Input UVLO and Soft-Start
  • Power Good and Output Overvoltage Protection
  • Available in HTSSOP-28 Package
  • Create a Custom Design Using the LM5176 with the WEBENCH Power Designer


  • Industrial PC Power Supplies
  • USB Power Delivery
  • Battery Powered Systems
  • LED Lighting


The LM5176 is a synchronous four-switch buck-boost DC/DC controller capable of regulating the output voltage at, above, or below the input voltage. The LM5176 operates over a wide input voltage range of 4.2 V to 55 V (60 V absolute maximum) to support a variety of applications.

The LM5176 employs current-mode control both in buck and boost modes of operation for superior load and line regulation. The switching frequency is programmed by an external resistor and can be synchronized to an external clock signal.

The device also features a programmable soft-start function and offers protection features including cycle-by-cycle current limiting, input undervoltage lockout (UVLO), output overvoltage protection (OVP), and thermal shutdown. In addition, the LM5176 features optional average input or output current limiting, optional spread spectrum to reduce peak EMI, and optional hiccup mode protection in sustained overload conditions.

Device Information

LM5176PWP HTSSOP-28 9.7 mm x 4.4 mm

Simplified Schematic

LM5176 simplified_schematic.gif