SNVS325E January   2005  – January 2016 LM2852

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1. 3.1 Efficiency vs ILOAD
  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 LM2852Y Typical Characteristics (500 kHz)
    7. 6.7 LM2852X Typical Characteristics (1500 kHz)
    8. 6.8 LM2852 Typical Characteristics (Both Y and X Versions)
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Split-Rail Operation
      2. 7.3.2 Switch Node Protection
    4. 7.4 Device Functional Modes
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Design Requirements
      2. 8.2.2 Detailed Design Procedure
        1. 8.2.2.1 Input Capacitor (CIN)
        2. 8.2.2.2 Soft-Start Capacitor (CSS)
        3. 8.2.2.3 Soft-Start Capacitor (CSS) and Fault Conditions
        4. 8.2.2.4 Compensation
        5. 8.2.2.5 Output Filter Values
        6. 8.2.2.6 Choosing an Inductance Value
        7. 8.2.2.7 Output Filter Inductors
        8. 8.2.2.8 Output Filter Capacitors
      3. 8.2.3 Application Curves
  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. 11.2 Community Resources
    3. 11.3 Trademarks
    4. 11.4 Electrostatic Discharge Caution
    5. 11.5 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

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

7 Detailed Description

7.1 Overview

The LM2852 is a DC-DC synchronous buck regulator. Integration of the PWM controller, power switches and compensation network greatly reduces the component count required to implement a switching power supply.

7.2 Functional Block Diagram

LM2852 20127012.gif

7.3 Feature Description

7.3.1 Split-Rail Operation

The LM2852 can be powered using two separate voltages for AVIN and PVIN. AVIN is the supply for the control logic; PVIN is the supply for the power FETs. The output filter components need to be chosen based on the value of PVIN. For PVIN levels lower than 3.3 V, use output filter component values recommended for 3.3 V. PVIN must always be equal to or less than AVIN.

LM2852 20127014.gif Figure 11. Split-Rail Operation

7.3.2 Switch Node Protection

The LM2852 includes protection circuitry that monitors the voltage on the switch pin. Under certain conditions, switching is disabled in order to protect the switching devices. One result of the protection circuitry may be observed when power to the LM2852 is applied with no or light load on the output. The output regulates to the rated voltage, but no switching may be observed. As soon as the output is loaded, the LM2852 begins normal switching operation.

7.4 Device Functional Modes

The LM2852 Enable pin is internally pulled up so that the part is enabled anytime the input voltage exceeds the UVLO threshold. A pulldown resistor can be used to set the enable input to low.