SNVS540K March   2009  – April 2019 LM2840 , LM2841 , LM2842

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Typical Application Circuit
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
    1.     Pin Functions
  6. 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 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Protection
    4. 7.4 Device Functional Modes
      1. 7.4.1 Continuous Conduction Mode
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Applications
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 Custom Design With WEBENCH® Tools
        2. 8.2.2.2 Setting the Output Voltage
        3. 8.2.2.3 Inductor Selection
        4. 8.2.2.4 Input Capacitor
        5. 8.2.2.5 Output Capacitor
        6. 8.2.2.6 Bootstrap Capacitor
        7. 8.2.2.7 Soft-Start Components
        8. 8.2.2.8 Shutdown Operation
        9. 8.2.2.9 Schottky Diode
      3. 8.2.3 Application Curves
      4. 8.2.4 Other Application Circuits
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Third-Party Products Disclaimer
      2. 11.1.2 Development Support
        1. 11.1.2.1 Custom Design With WEBENCH® Tools
    2. 11.2 Documentation Support
      1. 11.2.1 Related Documentation
    3. 11.3 Related Links
    4. 11.4 Receiving Notification of Documentation Updates
    5. 11.5 Community Resources
    6. 11.6 Trademarks
    7. 11.7 Electrostatic Discharge Caution
    8. 11.8 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

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

3 Description

The LM284xSIMPLE SWITCHER™ devices are PWM DC/DC buck (step-down) regulators. With an input range from 4.5 V to 42 V, they are suitable for a wide range of applications, such as power conditioning from unregulated sources. They feature a low RDSON (0.9‑Ω typical) internal switch for maximum efficiency (85% typical). Operating frequency is fixed at 550 kHz (X option) and 1.25 MHz (Y option), allowing the use of small external components while still being able to have low output voltage ripple. Soft start can be implemented using the shutdown (SHDN) pin with an external RC circuit allowing the user to tailor the soft-start time to a specific application.

The LM2840 is optimized for up to 100 mA, the LM2841 for up to 300 mA, and the LM2842 for up to 600‑mA load currents. They all have a 0.765-V nominal feedback voltage.

Additional features include: thermal shutdown, VIN undervoltage lockout, and gate-drive undervoltage lockout. The LM284x are available in a low-profile SOT-6L package.

Device Information(1)

PART NUMBER PACKAGE BODY SIZE (NOM)
LM2840, LM2841, LM2842 SOT (6) 1.60 mm × 2.90 mm
  1. For all available packages, see the orderable addendum at the end of the data sheet.