White LED driver ideal for ultra-bright displays

The SC442 device, with an integrated 3A boost power switch, is capable of driving up to 120 LEDs at up to 30mA per channel and is packaged in an ultra-small, low-profile 4.0 x 4.0 x 0.6mm, 28-pin, MLPQ package.

The high-density package, small external filter components, wide operating voltage range and high efficiency satisfy space-constrained LED backlights serving LCD monitors and LCD TVs.

The high-density LED driver extends Semtech's SC44x LED driver platform to address large LCD backlighting applications.

The SC442 operates across a wide input voltage range of 4.5V to 21V for use with lithium-ion battery packs or regulated 5V, 12V or 18V power supplies.

The device is capable of up to 42V output for driving up to 12 white LEDs per channel.

The device is compatible with boost (step-up) or Sepic (step-up/down) topologies.

It also transitions to bypass (or linear) mode when the input voltage is greater than the output voltage.

The synchronisation feature eliminates the inter-modulation noise found in backlight systems utilising multiple driver ICs such as those found in large LED backlit LCD TVs.

Other features include over-temperature, overload and open and programmable short LED protection.

Up to 50kHz PWM dimming eliminates audio noise problems.

The optimum LED output voltage is maintained dynamically by the internal DC-DC current-mode controller.

Channels can also be independently disabled for smaller panel designs.

Open LED and programmable shorted LED protection as well as over-temperature protection are provided.

The controller switching frequency is programmed from 200kHz to 1MHz to optimise efficiency and L/C filter sizing.

The SC442 LED driver is packaged in an MLPQ-UT 28-pin package with an exposed thermal pad for excellent heat sinking.

The driver is lead free, halogen free and fully RoHS compliant.

The SC442 joins the company's existing platform of LED backlight drivers, including the six-channel SC440A, the four-channel SC441A/C and the three-channel SC443 devices.

The SC442 is available immediately in production quantities and is priced at USD3.10 (GBP1.95) each in 3,000-piece lots.

The ordering code is SC442ULTRT.

Evaluation boards (SC442EVB) are also available.

Semtech offers comprehensive design assistance, including field- and factory-based support.