SNVS422D August   2006  – September 2015 LM2831

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and 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 Theory of Operation
      2. 7.3.2 Soft Start
      3. 7.3.3 Output Overvoltage Protection
      4. 7.3.4 Undervoltage Lockout
      5. 7.3.5 Current Limit
      6. 7.3.6 Thermal Shutdown
    4. 7.4 Device Functional Modes
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Applications
      1. 8.2.1 LM2831X Design Example 1
        1. 8.2.1.1 Design Requirements
        2. 8.2.1.2 Detailed Design Procedure
          1. 8.2.1.2.1 Inductor Selection
          2. 8.2.1.2.2 Input Capacitor
          3. 8.2.1.2.3 Output Capacitor
          4. 8.2.1.2.4 Catch Diode
          5. 8.2.1.2.5 Output Voltage
        3. 8.2.1.3 Application Curves
      2. 8.2.2 LM2831X Design Example 2
      3. 8.2.3 LM2831X Design Example 3
      4. 8.2.4 LM2831Y Design Example 4
      5. 8.2.5 LM2831Y Design Example 5
      6. 8.2.6 LM2831Z Design Example 6
      7. 8.2.7 LM2831Z Design Example 7
      8. 8.2.8 LM2831X Dual Converters with Delayed Enabled Design Example 8
      9. 8.2.9 LM2831X Buck Converter and Voltage Double Circuit With LDO Follower Design Example 9
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
      1. 10.1.1 Calculating Efficiency and Junction Temperature
      2. 10.1.2 Thermal Definitions
        1. 10.1.2.1 Silicon Junction Temperature Determination Method 1
      3. 10.1.3 WSON Package
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Device Support
      1. 11.1.1 Third-Party Products Disclaimer
    2. 11.2 Documentation Support
      1. 11.2.1 Related Documentation
    3. 11.3 Community Resources
    4. 11.4 Trademarks
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

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

1 Features

  • Space-Saving SOT-23 Package
  • Input Voltage Range of 3 V to 5.5 V
  • Output Voltage Range of 0.6 V to 4.5 V
  • 1.5-A Output Current
  • High Switching Frequencie
    • 1.6 MHz (LM2831X)
    • 0.55 MHz (LM2831Y)
    • 3 MHz (LM2831Z)
  • 130-mΩ PMOS Switch
  • 0.6-V, 2% Internal Voltage Reference
  • Internal Soft Start
  • Current Mode, PWM Operation
  • Thermal Shutdown
  • Overvoltage Protection

2 Applications

  • Local 5 V to Vcore Step-Down Converters
  • Core Power in HDDs
  • Set-Top Boxes
  • USB Powered Devices
  • DSL Modems

3 Description

The LM2831 regulator is a monolithic, high-frequency, PWM step-down DC-DC converter in a 5-pin SOT-23 and a 6-Pin WSON package. The LM2831 provides all the active functions to provide local DC-DC conversion with fast transient response and accurate regulation in the smallest possible PCB area. With a minimum of external components, the LM2831 is easy to use. The ability to drive 1.5-A loads with an internal 130-mΩ PMOS switch using state-of-the-art 0.5-µm BiCMOS technology results in the best power density available. The world-class control circuitry allows on-times as low as 30 ns, thus supporting exceptionally high frequency conversion over the entire 3 V to 5.5 V input operating range, down to the minimum output voltage of 0.6 V. Switching frequency is internally set to 550 kHz, 1.6 MHz, or 3 MHz, allowing the use of extremely small surface mount inductors and chip capacitors. Even though the operating frequency is high, efficiencies of up to 93% are easy to achieve. External shutdown is included, featuring an ultra-low standby current of 30 nA. The LM2831 utilizes current-mode control and internal compensation to provide high-performance regulation over a wide range of operating conditions. Additional features include internal soft-start circuitry to reduce inrush current, pulse-by-pulse current limit, thermal shutdown, and output overvoltage protection.

Device Information(1)

PART NUMBER PACKAGE BODY SIZE (NOM)
LM2831 WSON (6) 3.00 mm × 3.00 mm
SOT-23 (5) 1.60 mm × 2.90 mm
  1. For all available packages, see the orderable addendum at the end of the data sheet.

Typical Application Circuit

LM2831 20174864.gif

Efficiency vs Load

LM2831 20174881.gif