Semtech Debuts White LED Step-Up Converter with Integrated Schottky Diode

Semtech Corp. (Nasdaq:SMTC), a leading supplier of analog and mixed-signal semiconductors, announced the SC4509, the newest product addition to its handheld power management portfolio. The SC4509 is a step-up converter for white LED backlight applications with an integrated Schottky diode in a 2 x 2 x 0.8 mm package.

The SC4509 can drive up to five white LEDs in series to provide a tiny solution for small LCD displays. The device’s built-in Schottky diode saves board space and reduces costs while still providing efficiencies of over 80%, which is better than most competitive devices with integrated Schottky and similar to many that require an external Schottky.

To simplify control of the backlight, the device features a combination enable and PWM dimming pin that allows the user to turn the device on and off, or to apply a PWM dimming signal of up to 10kHz to control the output current level and dim the LEDs. This pin can also provide a soft start capability to reduce in-rush current at start up.

The SC4509 features extensive protection capabilities including over-voltage protection, current limit, thermal shutdown and open LED protection.

The input voltage range for the SC4509 is 2.7V to 10V, and the device can output up to 20V at 30mA. The device operates with a 1.2 MHz constant switching frequency. The SC4509 is available in either an MLPD-8 or SOT-23 package, both of which are RoHS compliant. Both packages assure a small overall footprint and cost effective solution.

“The SC4509 is one of the smallest LED boost converters on the market, and it integrates the Schottky diode while still delivering the efficiency one usually associates with larger solutions,” said Karl Volk, Director of Marketing for Handheld Power. “In portables with small displays where size and battery life are priorities, the SC4509 offers a compact layout and simple interface to ease the design-in process.”

Key Features of the SC4509

  • Drives up to 5 series white LEDs
  • Input voltage range: 2.7V – 10V
  • Integrated Schottky diode
  • Efficiencies of over 80%
  • Low 200mV feedback voltage
  • 1.2MHz PWM switching frequency
  • PWM dimming up to 10kHz
  • Small MLPD-W8 2 x 2 x 0.8mm package

Pricing and Availability
The SC4509 (order code: SC4509WLTRT for MLP 2×2 package) and (order code: SC4509SKTRT for SOT-23 package) are available immediately in production quantities and are priced at $0.37 each in 1,000-piece lots. Semtech offers comprehensive design assistance, including field- and factory-based support. Data sheets, volume pricing, and delivery quotes, as well as evaluation kits and samples, are available by contacting

About Semtech
Semtech Corporation is a leading supplier of high-quality analog and mixed-signal semiconductor products. The company is dedicated to providing customers with proprietary solutions and breakthrough technology in power management, protection, test & measurement, advanced communications and wireless connectivity products. Publicly traded since 1967, Semtech is listed on the NASDAQ National Market under the symbol SMTC. For more information, contact Semtech Corp. at 200 Flynn Road, Camarillo, CA 93012-8790; phone (805) 498-2111; email to