LT3476: Quad LED Driver Drives up to 32 1A LEDs & Offers 1000:1 True Color PWMTM Dimming -

MILPITAS, CA- August 14, 2006 - Linear Technology Corporation announces the LT3476, a 2MHz DC/DC converter designed to operate as a four channel constant current LED driver. Each channel of the LT3476 can drive up to eight 1A LEDs in series, enabling the LT3476 to drive up to 32 1A LEDs while delivering efficiencies up to 96%. Each of the four channels is operated by an independent True Color PWM signal, enabling each channel to be dimmed independently to ratios as high as 1000:1. A fixed frequency, current mode architecture ensures stable operation over a wide range of supply and output voltages. A frequency adjust pin enables the user to program the frequency between 200kHz and 2MHz to optimize efficiency while minimizing external component size. Its thermally enhanced 5mm x 7mm QFN package provide a highly compact solution footprint for 100W LED applications.

The LT3476 senses output current at the high side of the LED, enabling buck, buck-boost or boost configurations. With an external sense resistor, the user programs the output current range of each channel. Each of the 4 independent driver channels utilizes an internal 1.5A, 36V NPN switch. Other features include open LED protection and thermal limiting.

The LT3476EUHF is available from stock in a thermally enhanced 38-lead 5mm x 7mm DFN package. 1,000-piece pricing starts at $4.64 each and the device is available from stock.

Summary of Features: LT3476EUHF

• True Color PWMTM Dimming Delivers Up to 1000:1 Dimming Ratio
• LED Current Regulation with High-Side Sense
• VADJ Pin Accurately Sets LED Current Sense Threshold Over Range 10mV to 120mV
• Four Independent Driver Channels with 1.5A, 36V Internal NPN Switches
• Frequency Adjust Pin: 200kHz to 2MHz
• High Efficiency Conversion - Up to 96%
• Open LED Protection
• Low Quiescent Current
    ­   22mA in Active Mode
    ­  <10uA in Shutdown Mode
• Wide VIN Range: 2.8V to 16V
• Thermally Enhanced, 38-Lead, 5mm x 7mm QFN Package

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