DS3994 Rev 1 5/07 4-Channel Cold-Cathode Fluorescent Lamp Controller General Description Features High-Density CCFL Controller for LCD TV and The DS3994 is a 4-channel controller for cold-cathode PC Monitor Backlights fluorescent lamps (CCFLs) that backlight liquid crystal displays (LCDs) in TV and PC monitor applications. The Programmable Staggered Start for Burst Dimming DS3994s features make it suitable for use in even the on Each Channel largest LCDs, while its low BOM cost makes it ideal for Strike Frequency Boost Option the entire range of LCD TVs and monitors. Programmable Strike Time The DS3994 can stagger the lamp bursts from each of Can Be Easily Cascaded the four channels. This feature allows scanning back- Minimal External Components light schemes for video quality improvement to be Analog Brightness Control implemented using a single CCFL controller IC, making it very simple and inexpensive to provide this enhance- Gate Driver Phasing Minimizes DC Supply Current ment. In addition, staggering the bursts from each Surges channel can be used to minimize current ripple on the Per-Channel Lamp Fault Monitoring for Lamp display power supply, which is especially important for Open, Lamp Overcurrent, Failure to Strike, and larger LCDs. The relative stagger between each of the Overvoltage Conditions channels is programmable, so this feature can be tai- Accurate (2%) On-Board Oscillator Lamp lored to the specific application. Frequency (20kHz to 80kHz) The DS3994 uses a push-pull drive architecture but it Wide Range On-Board DPWM Burst-Dimming can also support full and half bridge drive schemes. Oscillator (22.5Hz to 440Hz) Contact the factory for more details. Can Be Synchronized to External Sources for the Lamp and DPWM Frequencies Applications < 10% to 100% Dimming Range LCD Televisions Soft-Start Minimizes Audible Transformer Noise 2 LCD PC Monitors I C-Compatible Serial Port and On-Board Nonvolatile (NV) Memory Allow Device Customization Pin Configurations 3-Byte NV User Memory for Storage of Serial Numbers and Date Codes TOP VIEW 4.5V to 5.5V Single-Supply Operation LOSC 1 28 LSYNC -40C to +85C Temperature Range A0 2 27 FAULT 28-Pin SO (300 mils) Package PSYNC 3 26 SCL POSC 4 25 SDA BRIGHT 5 24 OVD4 Ordering Information SVM 6 23 LCM4 DS3994 PART TEMP RANGE PIN-PACKAGE GA1 7 22 GB4 DS3994Z+ -40C to +85C 28 SO-300 GB1 8 21 GA4 +Denotes a lead-free package. LCM1 9 20 OVD3 OVD1 10 19 LCM3 GA2 11 18 GB3 GB2 12 17 GA3 LCM2 13 16 V CC OVD2 14 15 GND Typical Operating Circuits appear at end of data sheet. SO-300 Maxim Integrated Products 1 For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct at 1-888-629-4642, or visit Maxims website at www.maxim-ic.com.4-Channel Cold-Cathode Fluorescent Lamp Controller ABSOLUTE MAXIMUM RATINGS Voltage Range on V , SDA, and SCL Operating Temperature Range ...........................-40C to +85C CC Relative to Ground.............................................-0.5V to +6.0V EEPROM Programming Temperature Range .........0C to +70C Voltage Range on Leads Other than V , Storage Temperature Range .............................-55C to +125C CC SDA, and SCL..-0.5V to (V + 0.5V), Soldering Temperature...................See J-STD-020 Specification CC not to exceed +6.0V Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. RECOMMENDED OPERATING CONDITIONS (T = -40C to +85C.) A PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS Supply Voltage V (Note 1) 4.5 5.5 V CC V + CC Input Logic 1 V 2.2 V IH 0.3 Input Logic 0 V -0.3 0.8 V IL V + CC SVM Voltage Range V -0.3 V SVM 0.3 V + CC BRIGHT Voltage Range V -0.3 V BRIGHT 0.3 V + CC LCM Voltage Range V (Note 2) -0.3 V LCM 0.3 V + CC OVD Voltage Range V (Note 2) -0.3 V OVD 0.3 Gate-Driver Output Charge Q 20 nC G Loading ELECTRICAL CHARACTERISTICS (V = +4.5V to +5.5V, T = -40C to +85C.) CC A PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS G , G loaded with 600pF, A B Supply Current I 916 mA CC 4 channels active Input Leakage (Digital Pins) I -1.0 +1.0 A L Output Leakage (SDA, FAULT)I High impedance -1.0 +1.0 A LO V I = 3mA 0.4 Low-Level Output Voltage OL1 OL1 V (SDA, FAULT) V I = 6mA 0.6 OL2 OL2 Low-Level Output Voltage V I = 4mA 0.4 V OL3 OL3 (PSYNC, LSYNC) Low-Level Output Voltage V I = 4mA 0.4 V OL4 OL4 (GA, GB) High-Level Output Voltage V I = -1mA V - 0.4 V OH1 OH1 CC (PSYNC, LSYNC) 2 DS3994