SNVS656D September   2010  – October 2016 LM3492 , LM3492-Q1

PRODUCTION DATA.  

  1. Features
  2. Applications
  3. Description
  4. Revision History
  5. Description (continued)
  6. Pin Configuration and Functions
  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. 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 Bidirectional Communication Pin
        1. 8.3.9.1 Power-Good Indication
        2. 8.3.9.2 Overtemperature Indication
        3. 8.3.9.3 Output Current Undervoltage Indication
        4. 8.3.9.4 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. Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
        1. 9.2.2.1 RFB1, RFB2, and CFB
        2. 9.2.2.2 L1
        3. 9.2.2.3 D1
        4. 9.2.2.4 CIN and COUT
        5. 9.2.2.5 CVCC
        6. 9.2.2.6 CCDHC
        7. 9.2.2.7 RRT and RIREF
        8. 9.2.2.8 RCOMM
      3. 9.2.3 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 Documentation Support
      1. 12.1.1 Related Documentation
    2. 12.2 Related Links
    3. 12.3 Receiving Notification of Documentation Updates
    4. 12.4 Community Resources
    5. 12.5 Trademarks
    6. 12.6 Electrostatic Discharge Caution
    7. 12.7 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

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

Features

  • Boost Converter:
    • LM3492-Q1 is an Automotive Grade Product That is AEC Q100 Grade 1 Qualified
    • Very Wide Input Voltage Ranged
      From 4.5 V to 65 V
    • Programmable Soft Start
    • No Loop Compensation Required
    • Stable With Ceramic and Other Low ESR Capacitors With No Audible Noise
    • Nearly Constant Switching Frequency Programmable From 200 kHz to 1 MHz
  • Current Regulators:
    • Programmable LED Current from 50 mA to 200 mA
    • 1000:1 Contrast Ratio at a Dimming Frequency of More Than 3 kHz, Minimum LED Current Pulse Width is 300 ns
    • Two Individual Dimmable LED Strings up to
      65 V, Total 15 W (Typically 28 LEDs at
      150 mA)
    • Dynamic Headroom Control Maximizes Efficiency
    • Over-Power Protection
    • ±3% Current Accuracy
  • Supervisory Functions:
    • Precision Enable
    • COMM I/O Pin for Diagnostic and Commands
    • Thermal Shutdown Protection
    • Thermally Enhanced 20-Pin HTSSOP package

Applications

  • Ultra-High Contrast Ratio 6.5”-10” LCD Display Backlight up to 28 LEDs
  • Automotive or Marine GPS Displays

Description

The LM3492/-Q1 integrates a boost converter and a two-channel current regulator to implement a high efficient and cost effective LED driver for driving two individually dimmable LED strings with a maximum power of 15 W and an output voltage of up to 65 V. The boost converter employs a proprietary Projected-On-Time control method to give a fast transient response with no compensation required, and a nearly constant switching frequency programmable from 200 kHz to 1 MHz. The application circuit is stable with ceramic capacitors and produces no audible noise on dimming. The programmable peak current limit and soft-start features reduce current surges at start-up, and an integrated 190 mΩ, 3.9-A N-Channel MOSFET switch minimizes the solution size.

Device Information(1)

PART NUMBER PACKAGE BODY SIZE (NOM)
LM3492 HTSSOP (20) 7.80 mm × 4.40 mm
LM3492-Q1
  1. For all available packages, see the orderable addendum at the end of the data sheet.

Typical Application

LM3492 LM3492-Q1 30116101.gif