SNVS483H January 2007  – August 2017 LM25574


  1. Features
  2. Applications
  3. Description
  4. Revision History
  5. Pin Configuration and Functions
  6. Specifications
    1. 6.1Absolute Maximum Ratings
    2. 6.2ESD Ratings
    3. 6.3Recommended Operating Conditions
    4. 6.4Thermal Information
    5. 6.5Electrical Characteristics
    6. 6.6Typical Characteristics
  7. Detailed Description
    1. 7.1Overview
    2. 7.2Functional Block Diagram
    3. 7.3Feature Description
      1. 7.3.1High Voltage Start-Up Regulator
    4. 7.4Device Functional Modes
      1. 7.4.1Shutdown and Stand-by Mode
      2. 7.4.2Oscillator and Sync Capability
      3. 7.4.3Error Amplifier and PWM Comparator
      4. 7.4.4Ramp Generator
      5. 7.4.5Maximum Duty Cycle and Input Drop-out Voltage
      6. 7.4.6Current Limit
      7. 7.4.7Soft-Start
      8. 7.4.8Boost Pin
      9. 7.4.9Thermal Protection
  8. Application and Implementation
    1. 8.1Application Information
      1. 8.1.1 External Components
      2. 8.1.2 R3 (RT)
      3. 8.1.3 L1
      4. 8.1.4 C3 (CRAMP)
      5. 8.1.5 C9
      6. 8.1.6 C1
      7. 8.1.7 C8
      8. 8.1.8 C7
      9. 8.1.9 C4
      10. 8.1.10R5, R6
      11. 8.1.11R1, R2, C2
      12. 8.1.12R4, C5, C6
      13. 8.1.13Bias Power Dissipation Reduction
    2. 8.2Typical Application
      1. 8.2.1Typical Schematic for High Frequency (1MHz) Application
      2. 8.2.2Detailed Design Procedure
        1. Design With WEBENCH® Tools
  9. Layout
    1. 9.1Layout Guidelines
      1. 9.1.1PCB Layout and Thermal Considerations
    2. 9.2Layout Example
  10. 10Device and Documentation Support
    1. 10.1Device Support
      1. 10.1.1Developmental Support
        1. Design With WEBENCH® Tools
    2. 10.2Receiving Notification of Documentation Updates
    3. 10.3Community Resources
    4. 10.4Trademarks
    5. 10.5Electrostatic Discharge Caution
    6. 10.6Glossary
  11. 11Mechanical, Packaging, and Orderable Information


  • Integrated 42-V, 750-mΩ N-Channel MOSFET
  • Ultra-Wide Input Voltage From 6 V to 42 V
  • Adjustable Output Voltage as Low as 1.225 V
  • 1.5% Feedback Reference Accuracy
  • Operating Frequency Adjustable Between 50 kHz and 1 MHz With Single Resistor
  • Master or Slave Frequency Synchronization
  • Adjustable Soft-Start
  • Emulated Current Mode Control Architecture
  • Wide Bandwidth Error Amplifier
  • Built-In Protection
  • TSSOP-16 Package
  • Create a Custom Design Using the LM25574 With the WEBENCH® Power Designer


  • Industrial


The LM25574 is an easy to use buck regulator which allows design engineers to design and optimize a robust power supply using a minimum set of components. Operating with an input voltage range of 6 V to 42 V, the LM25574 delivers 0.5-A of continuous output current with an integrated 750-mΩ N-Channel MOSFET. The regulator utilizes an Emulated Current Mode architecture which provides inherent line regulation, tight load transient response, and ease of loop compensation without the usual limitation of low-duty cycles associated with current mode regulators. The operating frequency is adjustable from 50 kHz to 1-MHz to allow optimization of size and efficiency. To reduce EMI, a frequency synchronization pin allows multiple IC’s from the LM(2)557x family to self-synchronize or to synchronize to an external clock. The LM25574 guarantees robustness with cycle-by-cycle current limit, short-circuit protection, thermal shut-down, and remote shut-down. The device is available in a TSSOP-16 package. The LM25574 is supported by the full suite of WEBENCH® On-Line design tools.

Device Information(1)

LM25574TSSOP (16)5.00 mm × 4.40 mm
  1. For all available packages, see the orderable addendum at the end of the data sheet.

Simplified Application Schematic

LM25574 20214101.gif