Semtech's 28V Boost DC/DC Converter with Single Inductor Powers LCD Backlight and Camera Flash WLEDs in Smart Phones; SC4505 Is Available in 3X3MLPQ for Small, Slim Designs; Device Drives 12 White LEDs with Greater Than 82% Efficiency

Business Wire, March 7, 2006

CAMARILLO, Calif. -- Semtech Corp. (Nasdaq:SMTC), a leading supplier of analog and mixed-signal semiconductors for communications, portable devices, computers, and industrial equipment, today announced the SC4505, an integrated boost (step-up) dc/dc converter for driving white LEDs in LCD backlight and camera flash applications in cell phones and PDAs.

The SC4505 features a 2A power switch with an adjustable output voltage of up to 28V to drive two strings of up to six LEDs per string using a single inductor. Each string features an independent user-selectable current source with the backlight string supporting up to 75mA and the flash string supporting up to 125mA. The high power level can accommodate high-current LEDs for brighter displays.

The device supports independent control of the backlight and flash functions through separate pins. Backlight dimming can be achieved through digital PWM control signals with a range of 50Hz to 50 kHz, which maintain peak LED current for maximum brightness. The camera flash string features a user-controllable flash timeout that reduces LED burn out. In addition, the flash can be set to 20% of maximum flash current (torch or spotlight mode) for continuous LED lighting.

The converter operates at a nominal switching frequency of 1MHz with an input range of 2.6V to 16V. Driving the LEDs in series results in excellent current matching for uniform lighting. The SC4505's high operating frequency and higher integration reduces board space and BOM costs of the display/flash subsystem.

The SC4505 uses a regulation technique that optimizes its operation to seek the highest efficiency irrespective of load current in each string. This innovative power regulation technology adapts to the instantaneous power requirements of the system, reducing power dissipation while maintaining high efficiency.

"The single inductor design of the SC4505 enables a highly compact and lower cost backlight display and camera flash sub-system for next generation smart phones," said Ven Shan, Vice President of Marketing for Semtech's Power Management Products. "As handsets become portals for new video and imaging content, the SC4505 will allow smart phone system designers to develop sharper and brighter displays without sacrificing battery life."

The SC4505 can be used to drive up to 12 LEDs which makes it very flexible and suitable for driving backlight displays in devices such as PDAs, GPS devices, portable media players, and portable gaming consoles with 5-inch to 7-inch LCD displays. It comes in a 3x3mm, 16-pin MLPQ package that is lead free and RoHS/WEEE compliant.

Key Features of the SC4505

--Wide input voltage range of 2.6V - 12V

--Adjustable output voltage up to 30V

--Choice of two independent current sources for dual LED strands

--1MHz fixed frequency current-mode control

--Internal under-voltage lockout

--Internal 2A current limit for driving large number of LEDs

--Supports PWM Dimming from 50Hz to 50kHz

--Lead-free package is RoHS/WEEE compliant

Pricing and Availability

The SC4505 is available immediately in production quantities and is priced at $1.56 each in 1000-piece lots. Ordering code is SC4505MLTRT. 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 salesinfo@semtech.com.

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, advanced communications, human interface, test & measurement, 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 info@semtech.com; or visit its web site at www.semtech.com.

Semtech and the Semtech logo are marks of Semtech Corporation.