SNVSBK7A july   2021  – august 2023 LM5157

PRODUCTION DATA  

  1.   1
  2. 1 Features
  3. 2 Applications
  4. 3 Description
  5. 4 Revision History
  6. 5 Device Comparison Table
  7. 6 Pin Configuration and Functions
  8. 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
  9. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1  Line Undervoltage Lockout (UVLO/SYNC/EN Pin)
      2. 8.3.2  High Voltage VCC Regulator (BIAS, VCC Pin)
      3. 8.3.3  Soft Start (SS Pin)
      4. 8.3.4  Switching Frequency (RT Pin)
      5. 8.3.5  Dual Random Spread Spectrum – DRSS (MODE Pin)
      6. 8.3.6  Clock Synchronization (UVLO/SYNC/EN Pin)
      7. 8.3.7  Current Sense and Slope Compensation
      8. 8.3.8  Current Limit and Minimum On Time
      9. 8.3.9  Feedback and Error Amplifier (FB, COMP Pin)
      10. 8.3.10 Power-Good Indicator (PGOOD Pin)
      11. 8.3.11 Hiccup Mode Overload Protection (MODE Pin)
      12. 8.3.12 Maximum Duty Cycle Limit and Minimum Input Supply Voltage
      13. 8.3.13 Internal MOSFET (SW Pin)
      14. 8.3.14 Overvoltage Protection (OVP)
      15. 8.3.15 Thermal Shutdown (TSD)
    4. 8.4 Device Functional Modes
      1. 8.4.1 Shutdown Mode
      2. 8.4.2 Standby Mode
      3. 8.4.3 Run Mode
        1. 8.4.3.1 Spread Spectrum Enabled
        2. 8.4.3.2 Hiccup Mode Protection Enabled
  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 Recommended Components
        3. 9.2.2.3 Inductor Selection (LM)
        4. 9.2.2.4 Output Capacitor (COUT)
        5. 9.2.2.5 Input Capacitor
        6. 9.2.2.6 Diode Selection
      3. 9.2.3 Application Curve
    3. 9.3 System Examples
  11. 10Power Supply Recommendations
  12. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Examples
  13. 12Device and Documentation Support
    1. 12.1 Device Support
      1. 12.1.1 Third-Party Products Disclaimer
      2. 12.1.2 Development Support
        1. 12.1.2.1 Custom Design With WEBENCH® Tools
      3. 12.1.3 Export Control Notice
    2. 12.2 Documentation Support
      1. 12.2.1 Related Documentation
    3. 12.3 Receiving Notification of Documentation Updates
    4. 12.4 Support Resources
    5. 12.5 Trademarks
    6. 12.6 Electrostatic Discharge Caution
    7. 12.7 Glossary
  14. 13Mechanical, Packaging, and Orderable Information

Package Options

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

7.3 Recommended Operating Conditions

Over the recommended operating junction temperature range(1)
MIN NOM MAX UNIT
VSUPPLY Boost converter input (when BIAS ≥ 2.9 V) 1.5 45 V
VLOAD Boost converter output VSUPPLY 48 (2) V
VBIAS BIAS input(3) 2.9 45 V
VUVLO UVLO input 0 45 V
VFB FB input 0 4.0 V
ISW Switch current 0 See note(4) A
fSW Typical switching frequency 100 2200 kHz
fSYNC Synchronization pulse frequency 100 2200 kHz
TJ Operating junction temperature –40 125 °C
(1) Recommended Operating Conditions are conditions under the device is intended to be functional. For specifications and test conditions, see Electrical Characteristics .
(2) Boost converter output can be up to 48 V, but the SW pin voltage should be less than or equal to 50-V during transient.
(3) BIAS pin operating range is from 2.9 V to 45 V when VCC is supplied from the internal VCC regulator. When the VCC pin is directly connected to the BIAS pin, the device requires minimum 2.85 V at the BIAS pin to start up, and the  BIAS pin operating range is from 2.75 V to 5.5 V after starting up.
(4) Maximum switch currrent is limited by pre-programmed peak current limit (ILIM) , and is guaranteed when TJ < TTSD.