MAX8709ETI+

MAX8709ETI+ Features

♦ Synchronized to Resonant FrequencyLonger Lamp LifeGuaranteed Striking CapabilityHigh Power-to-Light Efficiency♦ Wide Input Voltage Range (4.6V to 28V)♦ Feed Forward for Excellent Line Rejection♦ SMBus Dimming Control Interface10:1 Dimming Range♦ Guaranteed 200Hz to 220Hz DPWM Frequency♦ Secondary Voltage Limit Reduces TransformerStress♦ Adjustable Lamp-Out Protection with 1s Timer♦ Secondary Current Limit Protects Against High-Voltage Short Circuits to Ground♦ Small 5mm x 5mm Thin QFN Package

MAX8709ETI+ General Description

The MAX8709 integrated backlight controller is optimizedto drive cold-cathode fluorescent lamps (CCFLs) using aresonant full-bridge inverter architecture. The resonantoperation maximizes striking capability and providesnear-sinusoidal waveforms over the entire input range toimprove CCFL lifetime. The controller operates over awide input voltage range of 4.6V to 28V with high power-to-light efficiency. The device also includes safety fea-tures that effectively protect against many single-pointfault conditions including lamp-out and short-circuit faults.The MAX8709 achieves 10:1 dimming range by “chop-ping” the lamp current on and off using a digital pulse-width-modulation (DPWM) method. The brightness iscontrolled with a 2-wire SMBus™-compatible interface.The device directly drives the four external N-channelpower MOSFETs of the full-bridge inverter. An internal5.3V linear regulator powers the MOSFET drivers, theDPWM oscillator, and most of the internal circuitry. TheMAX8709 is available in a space-saving 28-pin thin QFNpackage and operates over a -40°C to +85°C temp-erature range.

MAX8709ETI+ Applications

Notebook Computer DisplaysLCD TVsLCD MonitorsAutomotive Displays