Linear Technology Launches 32-Channel 30mA Buck LED Driver
Supports Dot Correction & Gray Scale Dimming

April 6, 2011 - Linear Technology Korea (CEO Hong Sa-kwak, www.linear.com) announced today the launch of a 32-channel LED driver (product name: LT3746) with an integrated 55V step-down controller. This LED driver can deliver up to 30mA LED current per channel, capable of driving serially connected LEDs up to 13V maximum, making it ideal for applications such as large LED signage. Each channel provides individual 6-bit dot correction current adjustment and 12-bit gray scale PWM dimming functionality. The LT3746, combined with a minimum 0.5µs LED on-time feature, delivers an extremely wide dynamic contrast ratio. Dot correction and gray scale dimming functions are accessible through a TTL/CMOS serial interface. The LT3746 is ideal for a wide range of input sources commonly used in commercial and industrial designs with an input voltage range of 6V to 55V. Additionally, by using minimal external components and a 5mm x 9mm QFN package, it provides a very compact solution footprint for multichannel applications.

The LT3746's internal buck controller generates an adaptive bus voltage slightly higher than the paralleled LED strings, delivering efficiency greater than 90%. 32 individual linear current sinks regulate and modulate individual LED strings, providing extensive functionality in a compact solution footprint. The LT3746 provides complete diagnostic and protection functions against LED open/short and thermal error conditions, along with error status reporting through a serial data interface. Through a fully buffered 30MHz, skew-balanced, cascadable serial interface, the LT3746 is ideal for full-color LED displays as well as large-screen LCD dynamic backlighting.

The LT3746EUHH is currently available in a 56-pin 5mm x 9mm QFN package, with product pricing starting at $4.95 for 1,000-unit quantities. The extended temperature version LT3746IUHH or I-grade