Features: ·SMBus Slave Address (0x58) for Wide Dimming Range Inverters
·Guaranteed 200Hz to 220Hz DPWM Frequency
·Externally Synchronizable DPWM Frequency
·Lamp-Out Protection with 1s Timeout
·Synchronized to Resonant Frequency Good Crest Factor for Longer Lamp Life Ensures Maximum Strike Capability
·High Power-to-Light Efficiency
·Wide Dimming Range (3 Methods) Lamp Current Adjust: >3 to 1 DPWM: >10 to 1 Combined: >30 to 1
·Feed-Forward for Fast Response to Step Change of Input Voltage
·Wide Input-Voltage Range (4.6V to 28V)
·Transformer Secondary Voltage Limiting to Reduce Transformer Stress
·Protected Against Short-Circuit and Other Single- Point Faults
·Dual-Mode Brightness Control Interface
·Small Footprint 28-Pin QFN (5mm × 5mm) PackageApplication·Notebook Computers
·Multibulb LCD Monitors
·Portable Display ElectronicsPinout
SpecificationsBATT to GND.......................................................-0.3V to +30V
BST1, BST2 to GND ............................................-0.3V to +36V
BST1 to LX1, BST2 to LX2 ....................................-0.3V to +6V
GH1 to LX1 ............................................-0.3V to (BST1 + 0.3V)
GH2 to LX2 ............................................-0.3V to (BST2 + 0.3V)
VCC, VDD to GND .................................................-0.3V to +6V
REF, ILIM to GND......................................-0.3V to (VCC + 0.3V)
GL1, GL2 to GND......................................-0.3V to (VDD + 0.3V)
MINDAC, IFB, CCV, CCI to GND ............................-0.3V to +6V
MODE to GND6V to +6V.........................................-6V to +12V
VFB to GND........................................................-0.3V to +0.3V
CRF/SDA, CTL/SCL, SH/SUS to GND ......................-0.3V to +6V
PGND to GND .....................................................-0.3V to +0.3V
Continuous Power Dissipation (TA = +70)
28-Pin QFN (derate 20.84mW/ above +70) ...........1667mW
Operating Temperature Range ...........................-40 to +85
Storage Temperature Range .............................-65 to +150
Lead Temperature (soldering, 10s) ................................+300
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.
DescriptionThe MAX1996A integrated controller is optimized to drive cold-cathode fluorescent lamps (CCFLs) using synchronized full-bridge inverter architecture.
Synchronized drive provides near sinusoidal waveforms over the entire input range to maximize the life of CCFLs. The controller also operates over a wide inputvoltage range with high efficiency and broad dimming range.
The MAX1996A includes safety features that limit the transformer secondary voltage and protect against single- point fault conditions including lamp-out and shortcircuit faults.
The MAX1996A regulates the CCFL brightness in three ways: linearly controlling the lamp current, digital pulsewidth modulating (DPWM) the lamp current, or using both methods simultaneously to achieve the widest dimming range (>30:1). CCFL brightness can be controlled with either an analog voltage or a 2-wire SMBus™-compatible interface. The device directly drives the four external N-channel power MOSFETs of the full bridge inverter. An internal 5.3V linear regulator powers the MOSFET drivers, the synchronizable DPWM oscillator, and most of the internal circuitry.
The MAX1996A has the same pin configuration as the MAX1895, but with modified SMBus slave address (0x58) and command bytes. In addition, the lamp-out protection timer has been reduced to approximately 1s and the DPWM frequency is guaranteed from 200Hz to 220Hz over the operating temperature range without external components or trimming. The MAX1996A is available in the space-saving 28-pin QFN package and operates over a -40° to +85 temperature range.
MAX1996A Data Sheet
