SNVSA37A October   2015  – May 2016 LM5175

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Simplified Schematic
  5. 5 Revision History
  6. 6 Pin Configuration and Functions
  7. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics
    6. 7.6 Typical Characteristics
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature 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  CCM/DCM Operation
      8. 8.3.8  Frequency and Synchronization (RT/SYNC)
      9. 8.3.9  Frequency Dithering
      10. 8.3.10 Output Overvoltage Protection (OVP)
      11. 8.3.11 Power Good (PGOOD)
      12. 8.3.12 Gm Error Amplifier
      13. 8.3.13 Integrated Gate Drivers
      14. 8.3.14 Thermal Shutdown
    4. 8.4 Device Functional Modes
      1. 8.4.1 Shutdown, Standby, and Operating Modes
      2. 8.4.2 MODE Pin Configuration
  9. 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  VOUT
        4. 9.2.2.4  Inductor Selection
        5. 9.2.2.5  Output Capacitor
        6. 9.2.2.6  Input Capacitor
        7. 9.2.2.7  Sense Resistor (RSENSE)
        8. 9.2.2.8  Slope Compensation
        9. 9.2.2.9  UVLO
        10. 9.2.2.10 Soft-Start Capacitor
        11. 9.2.2.11 Dither Capacitor
        12. 9.2.2.12 MOSFETs QH1 and QL1
        13. 9.2.2.13 MOSFETs QH2 and QL2
        14. 9.2.2.14 Frequency Compensation
      3. 9.2.3 Application Curves
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Custom Design with WEBENCH Tools
    2. 12.2 Receiving Notification of Documentation Updates
    3. 12.3 Documentation Support
      1. 12.3.1 Related Documentation
    4. 12.4 Community Resources
    5. 12.5 Trademarks
    6. 12.6 Electrostatic Discharge Caution
    7. 12.7 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

1 Features

  • Single Inductor Buck-Boost Controller for Step-Up/Step-Down DC/DC Conversion
  • Wide VIN Range: 3.5 V to 42 V, 60 V Maximum
  • Flexible VOUT Range: 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
  • Selectable CCM or DCM with Pulse Skipping
  • Available in HTSSOP-28 and QFN-28 Packages
  • Create a Custom Design Using the LM5175 with the WEBENCH Power Designer

2 Applications

  • Automotive Start-Stop Systems
  • Backup Battery and Supercapacitor Charging
  • Industrial PC Power Supplies
  • USB Power Delivery
  • LED Lighting

3 Description

The LM5175 is a synchronous four-switch buck-boost DC/DC controller capable of regulating the output voltage at, above, or below the input voltage. The LM5175 operates over a wide input voltage range of 3.5 V to 42 V (60 V maximum) to support a variety of applications.

The LM5175 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 LM5175 features selectable Continuous Conduction Mode (CCM) or Discontinuous Conduction Mode (DCM) operation, 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

ORDER NUMBER PACKAGE BODY SIZE
LM5175PWP HTSSOP-28 9.7 mm x 4.4 mm
LM5175RHF QFN-28 4.0 mm x 5.0 mm

4 Simplified Schematic

LM5175 schematic_frontpage.gif