Linear Technology Corp. 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 and it is available from stock.
The LT3496IUFD operates from a -40°C to 125°C operating junction temperature, is priced at $4.20 in 1,000-piece quantities and is available from stock.