Semtech's Highly Integrated, Programmable PWM Controller Vastly Eases Design of Isolated Telecom, Networking, and Industrial Power Supplies

Semtech Corp. (Nasdaq: SMTC) a leading supplier of analog and mixed-signal semiconductors for communications, computers, and industrial equipment, today announced the SC4808 Precision High-Speed Double-End, PWM controller, a uniquely feature-rich addition to the company's growing portfolio of PWM controller products.

Among the SC4808's most noteworthy pluses are its pace-setting ability to work in voltage- or peak-current-mode, offering unprecedented design flexibility, and its ripple-reducing synchronized bi-phase operation that optimizes dual controller designs. Additional benefits include a switching frequency that reaches to 1-MHz; a dual-output drive circuit; and its impressively high integration, which includes support circuitry for building isolated power-supplies that use an external secondary-side error amplifier.

Targeting high-density, medium- to high-power (50W to 1000W) applications, the SC4808 can serve as the foundation for isolated buck power supplies having push-pull, half-bridge, full-bridge, or interleaved-forward converter topologies. Such supplies, which often deliver power at the point of load, are typically specified for telecom, networking, and industrial products. For added flexibility, the SC4808 is available in two versions: one with a turn-on threshold of 12.5V; the other, at 4.5V.

"The SC4808 significantly expands Semtech's portfolio of PWM controllers for designers of isolated power supplies for telecom, networking, and industrial equipment," said George Georgalis, Semtech's Director of Telecom Power Management Products. "The controller's high level of integration and wide range of features, including its unique programmable voltage- or current-mode operation and bi-phase clock synchronization, are aimed at benefiting designers while streamlining procurement and manufacturing. High performance, ease of use, small size, and low system cost are the main reasons designers will pick the SC4808 over its competition."

The SC4808's programmable operating mode lets designers pick one and the same chip for a wide range of topologies, cutting their learning curve while easing procurement, inventory, and manufacturing headaches. Moreover, by exploiting the IC's synchronized bi-phase clocking feature, designs can supply two voltages using separate converters while minimizing input ripple and input filter size. Bi-phase operation ensures a 180° phase difference between controller clock signals, relaxing input-filter requirements.

Other features packed into the SC4808 include a clock frequency, set by an external resistor, that can be programmed to 1 MHz and externally synchronized; a dual-output drive stage in push-pull configuration; soft start-up operation with a 120-µA start-up current; cycle-by-cycle current limiting; and programmable line-undervoltage lock out (LUVLO) with hysteresis.

Key Features

• Uniquely programmable for voltage or current mode PWM topologies

• Unique bi-phase operation minimizes input ripple for given filter capacitors

• Programmable switching frequency to 1 MHz and external synchronization

• Highly integrated, including drive circuitry for isolated power supplies

• Dual-output drive stage in push-pull configuration

• Soft start-up with 120-µA current, cycle-by-cycle current limiting

• Programmable LUVLO

• Space-saving MSOP-10 package

• 4.5V and 12.5V turn-on threshold versions

Pricing and Availability

The SC4808 High-Performance, Dual-Ended PWM controller comes in an MSOP-10 package, is rated for operation from –40°C to 105°C, and is available now from Semtech's authorized network of sales representatives and distributors. Pricing starts at $1.30 each in production quantities of 1000 or more. Engineers designing in the SC4808 can leverage Semtech's comprehensive assistance services, including field- and factory-based support. Datasheets are available at www.semtech.com.

About Semtech

Semtech Corporation is a leading supplier of high-quality analog and mixed-signal ICs for power management, over-voltage and transient protection, human interface devices & system management, high-performance applications, and advanced communications. 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.