SNVS797B March   2012  – October 2015 LM3492HC , LM3492HC-Q1

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Description (continued)
  6. 6 Pin Configuration and Functions
  7. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics
    6. 7.6 Typical Characteristics
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1  Switching Frequency
      2. 8.3.2  LDO Regulator
      3. 8.3.3  Enable and Disable
      4. 8.3.4  Current Limit
      5. 8.3.5  Thermal Protection
      6. 8.3.6  Dynamic Headroom Control, Over-Ride, and Soft-Start
      7. 8.3.7  Current Regulator
      8. 8.3.8  Output Voltage Feedback
      9. 8.3.9  Overvoltage Protection
      10. 8.3.10 Bidirectional Communication Pin
        1. 8.3.10.1 Power-Good Indication
        2. 8.3.10.2 Overtemperature Indication
        3. 8.3.10.3 Output Current Undervoltage Indication
        4. 8.3.10.4 Switching Frequency Tuning
    4. 8.4 Device Functional Modes
    5. 8.5 Programming
      1. 8.5.1 Output Current Overvoltage Indication
      2. 8.5.2 COMM Pin Bit Pattern
      3. 8.5.3 Channel 1 Disable
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
        1. 9.2.1.1 RFB1, RFB2, and CFB
        2. 9.2.1.2 L1
        3. 9.2.1.3 D1
        4. 9.2.1.4 CIN and COUT
        5. 9.2.1.5 CVCC
        6. 9.2.1.6 CCDHC
        7. 9.2.1.7 RRT and RIREF
        8. 9.2.1.8 RCOMM
      2. 9.2.2 Application Curve
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Related Links
    2. 12.2 Community Resources
    3. 12.3 Trademarks
    4. 12.4 Electrostatic Discharge Caution
    5. 12.5 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

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

5 Description (continued)

To maximize the efficiency, dynamic headroom control (DHC) automatically adjusts the output voltage to a minimum. The DHC also facilitates a single BOM for different number of LED in a string, which is required for back-light panels of different size, thereby reducing overall development time and cost. The LM3492HC device includes a COMM pin that serves as a bidirectional I/O pin. The versatile COMM pin interface with an external micro-controller unit (MCU) is used for the following functions: power-good, overtemperature, IOUT overvoltage and undervoltage indications, switching frequency tuning, and channel 1 disabling. Other supervisory functions of the device include precise enable, VCC undervoltage lockout, current regulator over-power protection, and thermal shutdown protection. The device is available in the thermally enhanced PWP, 20-pin package.