DS3994 Datasheet, PDF (1/28 Pages) Maxim Integrated Products – 4-Channel Cold-Cathode Fluorescent Lamp Controller

Rev 0; 10/06
4-Channel Cold-Cathode
Fluorescent Lamp Controller
General 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 back-
light schemes for video quality improvement to be
implemented using a single CCFL controller IC, making
it very simple and inexpensive to provide this enhance-
ment. 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 tai-
lored 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.
LCD Televisions
LCD PC Monitors
Applications
Pin Configurations
TOP VIEW
LOSC 1
A0 2
PSYNC 3
POSC 4
BRIGHT 5
SVM 6
GA1 7
GB1 8
LCM1 9
OVD1 10
GA2 11
GB2 12
LCM2 13
OVD2 14
DS3994
SO-300
28 LSYNC
27 FAULT
26 SCL
25 SDA
24 OVD4
23 LCM4
22 GB4
21 GA4
20 OVD3
19 LCM3
18 GB3
17 GA3
16 V_CC
15 GND
Features
o High-Density CCFL Controller for LCD TV and
PC Monitor Backlights
o Programmable Staggered Start for Burst Dimming
on Each Channel
o Strike Frequency Boost Option
o Programmable Strike Time
o Can Be Easily Cascaded
o Minimal External Components
o Analog Brightness Control
o Gate Driver Phasing Minimizes DC Supply Current
Surges
o Per-Channel Lamp Fault Monitoring for Lamp
Open, Lamp Overcurrent, Failure to Strike, and
Overvoltage Conditions
o Accurate (±2%) On-Board Oscillator Lamp
Frequency (20kHz to 80kHz)
o Wide Range On-Board DPWM Burst-Dimming
Oscillator (22.5Hz to 440Hz)
o Can Be Synchronized to External Sources for the
Lamp and DPWM Frequencies
o < 10% to 100% Dimming Range
o Soft-Start Minimizes Audible Transformer Noise
o I²C-Compatible Serial Port and On-Board
Nonvolatile (NV) Memory Allow Device
Customization
o 3-Byte NV User Memory for Storage of Serial
Numbers and Date Codes
o 4.5V to 5.5V Single-Supply Operation
o -40°C to +85°C Temperature Range
o 28-Pin SO (300 mils) Package
Ordering Information
PART
TEMP RANGE
DS3994Z+
-40°C to +85°C
+Denotes lead-free package.
PIN-PACKAGE
28 SO-300
Typical Operating Circuits appear at end of data sheet.
______________________________________________ Maxim Integrated Products 1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.