LInear triple output LED driver drives up to 24 x 500mA LEDs, offers 3,000:1 true color PWM dimming

Date Announced: 11 Jan 2007 Linear Technology has announced the LT3496, a 2MHz DC/DC converter designed to operate as a three-channel constant current LED driver. Each of the LT3496's three channels can drive up to eight 500mA LEDs in series, enabling it to drive up to 24 x 500mA LEDs at efficiencies up to 96%. All three channels are operated by an independent True Color PWM™ signal, enabling each to be dimmed independently to ratios as high as 3,000:1. 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 330kHz and 2.1MHz to optimize efficiency while minimizing external component size. The LT3496's thermally enhanced 4mm x 5mm QFN package provides a highly compact solution footprint for 50W LED applications.The LT3496 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 three independent driver channels utilizes an internal 750mA, 45V NPN switch and has a built in gate driver for PMOS disconnect. Other features include open LED protection and thermal limiting.The LT3496EUFD is available from stock in a thermally enhanced 28-lead 4mm x 5mm QFN package. 1,000-piece pricing starts at $3.50 each.The LT3496IUFD is available from stock and is tested and guaranteed to operate from a -40°C to 125°C operating junction temperature, it is priced at $4.20 in 1,000-piece quantities.Summary of Features of the LT3496:* True Color PWM Dimming Delivers up to 3000:1 Dimming Ratio * Built-In Gate Driver for PMOS LED Disconnect * Three Independent Driver Channels with 700mA, 45V Internal Switches * Operates in Buck, Boost, Buck-Boost Modes * CTRL Pin Accurately Sets LED Current Sense Threshold Over a Range of 10mV to 100mV * Low Quiescent Current: 6mA in Active Mode * <10uA in Shutdown Mode * Adjustable Switching Frequency: 300kHz to 2.1MHz * Open LED Protection * Wide Input Voltage Range: 3V to 40V * Surface Mount Components * 28-Lead (4mm x 5mm) QFN Package

Contact
UK, Ireland, South Africa and Israel: Alastair Boyd, Linear Technology (UK) Limited Tel: +44 (0)1628 477066 E-mail: [email protected] North America and General Information: Doug Dickinson, Linear Technology Corporation Tel: (408) 432 1900 ext. 2233 E-mail: [email protected]

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