SNVS227H February   2003  – January 2015 LP3872 , LP3875

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 Shutdown (SD)
      2. 7.3.2 Load Voltage Sense
      3. 7.3.3 Short-Circuit Protection
      4. 7.3.4 Low Dropout Voltage
    4. 7.4 Device Functional Modes
      1. 7.4.1 Shutdown Mode
      2. 7.4.2 Active Mode
      3. 7.4.3 ERROR Flag Operation
  8. 8 Application and Implementation
    1. 8.1 Application Information
      1. 8.1.1 Dropout Voltage
      2. 8.1.2 Reverse Current Path
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 Power Dissipation and Device Operation
        2. 8.2.2.2 External Capacitors
        3. 8.2.2.3 Selecting a Capacitor
        4. 8.2.2.4 Capacitor Characteristics
          1. 8.2.2.4.1 Ceramic
          2. 8.2.2.4.2 Tantalum
          3. 8.2.2.4.3 Aluminum
        5. 8.2.2.5 Turnon Characteristics for Output Voltages Programmed to 2 V or Less
        6. 8.2.2.6 RFI/EMI Susceptibility
        7. 8.2.2.7 Output Noise
      3. 8.2.3 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Examples
  11. 11Device and Documentation Support
    1. 11.1 Related Links
    2. 11.2 Trademarks
    3. 11.3 Electrostatic Discharge Caution
    4. 11.4 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

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1 Features

  • Input Voltage Range: 2.5 V to 7 V
  • Ultra Low-Dropout Voltage
  • Low Ground Pin Current
  • Load Regulation of 0.06%
  • 10-nA Quiescent Current in Shutdown Mode
  • Ensured Output Current of 1.5-A DC
  • Available in DDPAK/TO-263, TO-220, and
    SOT-223 Packages
  • Output Voltage Accuracy ± 1.5%
  • ERROR Flag for Output Status
  • Sense Option Improves Load Regulation
  • Minimum Output Capacitor Requirements
  • Overtemperature/Overcurrent Protection
  • −40°C to 125°C Junction Temperature Range

2 Applications

  • Microprocessor Power Supplies
  • GTL, GTL+, BTL, and SSTL Bus Terminators
  • Power Supplies for DSPs
  • SCSI Terminators
  • Post Regulators
  • High Efficiency Linear Regulators
  • Battery Chargers
  • Other Battery-Powered Applications

LP3872 Typical Application Circuit

20063301.png
*SD and ERROR pins must be pulled high through a 10-kΩ pullup resistor. Connect the ERROR pin to ground if this function is not used. See the Shutdown Mode and ERROR Flag Operation sections.

3 Description

The LP387x series of fast ultra low-dropout linear regulators operate from a 2.5-V to 7-V input supply. Wide range of preset output voltage options are available. These ultra low-dropout linear regulators respond very quickly to step changes in load, which makes them suitable for low-voltage microprocessor applications. The LP3872 and LP3875 are developed on a CMOS process which allows low quiescent current operation independent of output load current. This CMOS process also allows the LP3872 and LP3875 to operate under extremely low dropout conditions.

Dropout Voltage: Ultra low-dropout voltage; typically 38 mV at 150-mA load current and 380 mV at 1.5-A load current.

Ground Pin Current: Typically 6 mA at 1.5-A load current.

Shutdown Mode: Typically 10-nA quiescent current when the SD pin is pulled low.

ERROR Flag: ERROR flag goes low when the output voltage drops 10% below nominal value (LP3872 only).

SENSE: Sense pin improves regulation at remote loads (LP3875 only).

Precision Output Voltage: Multiple output voltage options are available ranging from 1.8 V to 5 V with a specified accuracy of ±1.5% at room temperature, and ±3.0% over all conditions (varying line, load, and temperature).

Device Information(1)

PART NUMBER PACKAGE BODY SIZE (NOM)
LP3872 SOT-223 (5) 6.50 mm × 3.56 mm
TO-263 (5) 10.16 mm × 8.42 mm
LP3875 SOT-223 (5) 6.50 mm × 3.56 mm
TO-263 (5) 10.16 mm × 8.42 mm
TO-220 (5) 14.986 mm × 10.16 mm
  1. For all available packages, see the orderable addendum at the end of the datasheet.

LP3875 Typical Application Circuit

20063345.png
*SD must be pulled high through a 10-kΩ pullup resistor. See the Shutdown Mode section.

4 Revision History

Changes from G Revision (December 2014) to H Revision

  • Added Input voltage range as first Feature Go
  • Added "(LP3872 only)" Go
  • Added "(LP3875 only)" Go
  • Changed all VIN and VOUT pin names to IN and OUT in drawings and textGo
  • Changed footnotes to appear under each table Go
  • Deleted CDM footnote Go
  • Deleted last sentence of Short-Circuit Protection subsection Go

Changes from F Revision (April 2013) to G Revision

  • Added Pin Configuration and Functions section, ESD Ratings table, Feature Description section, Device Functional Modes, Application and Implementation section, Power Supply Recommendations section, Layout section, Device and Documentation Support section, and Mechanical, Packaging, and Orderable Information section; update thermal values Go