Products, Materials + Tools | Jul 16, 2010

Linear Technology LT3496: Triple Output LED Driver Drives Up to Eight 500mA LEDs in Series

Linear Technology announces the H-grade version of the LT3496. The LT3496 is a 2MHz DC/DC converter designed to operate as a three-channel constant current LED driver. Each of the device’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%.

The H-grade version operates up to a junction temperature of 150?C, compared to the E- and I-grade versions’ 125?C maximum junction temperature. All electrical specifications are identical for the E-, I- and H-grade versions. The H-grade parts are tested and guaranteed to the maximum junction temperature of 150?C. They are ideal for automotive and industrial applications which are subjected to high ambient temperatures.

The LT3496 senses output current at the high side of the LED, enabling buck, buck-boost or boost configurations. Each channel is 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.

Summary of Features: LT3496H:
• Maximum Junction Temperature of 150°C
• 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

The LT3496HUFD is available from stock in a 4mm x 5mm QFN-28 package. Pricing starts at $4.45 each for 1,000 piece quantities. For more information, visit www.linear.com/pr/3496.

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