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DS3994
4-Channel Cold-Cathode Fluorescent Lamp Controller

Allows the Implementation of Scanning Backlight Schemes Using Only One CCFL Controller IC


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Data Sheet
FULL DATA SHEET (PDF, 444kB)
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Description
The DS3994 is a 4-channel controller for cold-cathode fluorescent lamps (CCFLs) that backlight liquid crystal displays (LCDs) in TV and PC monitor applications. The DS3994's features make it suitable for use in even the largest LCDs, while its low BOM cost makes it ideal for the entire range of LCD TVs and monitors.

The DS3994 can stagger the lamp bursts from each of the four channels. This feature allows scanning backlight schemes for video quality improvement to be implemented using a single CCFL controller IC, making it very simple and inexpensive to provide this enhancement. In addition, staggering the bursts from each channel can be used to minimize current ripple on the display power supply, which is especially important for larger LCDs. The relative stagger between each of the channels is programmable, so this feature can be tailored to the specific application.

The DS3994 uses a push-pull drive architecture but it can also support full and half bridge drive schemes. Contact the factory for more details.

Key Features   Applications/Uses
  • High-Density CCFL Controller for LCD TV and PC Monitor Backlights
  • Programmable Staggered Start for Burst Dimming on Each Channel
  • Strike Frequency Boost Option
  • Programmable Strike Time
  • Can Be Easily Cascaded
  • Minimal External Components
  • Analog Brightness Control
  • Gate Driver Phasing Minimizes DC Supply Current Surges
  • Per-Channel Lamp Fault Monitoring for Lamp Open, Lamp Overcurrent, Failure to Strike, and Overvoltage Conditions
  • Accurate (±2%) On-Board Oscillator Lamp Frequency (20kHz to 80kHz)
  • Wide Range On-Board DPWM Burst-Dimming Oscillator (22.5Hz to 440Hz)
  • Can Be Synchronized to External Sources for the Lamp and DPWM Frequencies
  • < 10% to 100% Dimming Range
  • Soft-Start Minimizes Audible Transformer Noise
  • I²C-Compatible Serial Port and On-Board Nonvolatile (NV) Memory Allow Device Customization
  • 3-Byte NV User Memory for Storage of Serial Numbers and Date Codes
  • 4.5V to 5.5V Single-Supply Operation
  • -40°C to +85°C Temperature Range
  • 28-Pin SO (300 mils) Package

 
  • LCD PC Monitors
  • LCD-TVs

    Key Specifications:   CCFL Controllers
    Part Number Features VIN (min) (V) VIN (max) (V) Applications Topology Number of Channels Dimming Interface Frequency EV-Kit RoHS Available Package Operating Temp. Range (°C) Price**
    DS3994 
    All N-FET Drive
    Lamp Fault Output
    Master-Slave Function
    Status Registers
    Synchonizable
    User EEPROM
    4.5 5.5
    Monitors
    TVs
    Push-Pull 4 Analog
    DPWM
    I2C
    SMBus
    Fixed PWM No Yes SOIC/28 -40 to +85 $0.99 @ 1k
    See All CCFL Controllers (18)
    Notes:
    **This pricing is BUDGETARY, for comparing similar parts. Prices are in U.S. dollars and subject to change. Quantity pricing may vary substantially and international prices may differ due to local duties, taxes, fees, and exchange rates. For volume-specific prices and delivery, please see the price and availability page or contact an authorized distributor.

    Diagram
    DS3994: Typical Operating Circuit
    Typical Operating Circuit

    Application Notes
  • Application Note 3375: DS3984 / DS3988 Transformer Turns Ratio Selection - DS3994
  • Application Note 3835: CCFL Push-Pull Snubber Circuit - DS3994
  • Application Note 3898: Calculator Simplifies Programming the Burst Dimming Stagger on the DS3994 Cold-Cathode Fluorescent Lamp (CCFL) Controller - DS3994
  • Application Note 4135: Implementing Analog Dimming on the DS39xx CCFL Controllers - DS3994
  • Application Note 4147: How to Modify the Soft-Start Profile of the DS3994 - DS3994
  • Application Note 4190: Enhancing the Gate-Drive Capacity of the DS39xx CCFL Controllers - DS3994

    Evaluation Kits
    none

    Design Guides
  • DISPLAYS (PDF)
  • FLAT-PANEL DISPLAY (PDF)

    Reliability Reports
  • Reliability Report: DS3994.pdf

    Software/Models
    none

    Ordering Information
    Notes:

    1. Other options and links for purchasing parts are listed at: http://www.maxim-ic.com/sales.
    2. Didn't Find What You Need? Ask our applications engineers. Expert assistance in finding parts, usually within one business day.
    3. Part number suffixes: T or T&R = tape and reel; + = RoHS/lead-free; # = RoHS/lead-exempt. More: SeeFull Data Sheet or Part Naming Conventions.
    4. * Some packages have variations, listed on the drawing. "PkgCode/Variation" tells which variation the product uses. Note that "+", "#", "-" in the part number suffix describes RoHS status. Package drawings may show a different suffix character.


    Devices: 1-2 of 2

    DS3994 Free
    Sample
    Buy
    Package: TYPE PINS FOOTPRINT
      DRAWING CODE/VAR *
    Temp RoHS/Lead-Free?
    Materials Analysis
    DS3994Z+T&R  
    SOIC;28 pin;

    Use pkgcode/variation: W28+1*
    -40°C to +85°C RoHS/Lead-Free: Lead Free
    Materials Analysis
    DS3994Z+  
    SOIC;28 pin;

    Use pkgcode/variation: W28+1*
    -40°C to +85°C RoHS/Lead-Free: Lead Free
    Materials Analysis

    More Information
  • New Product Press Release 2006-12-20 
  • Product Ad: Download

    Related Products
    DS3988 8-Channel Cold-Cathode Fluorescent Lamp Controller
    DS3984 4-Channel Cold-Cathode Fluorescent Lamp Controller

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    2007-05-22
    This page last modified: 2007-11-29




             


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