Semtech Rolls Out Efficient, Feature-Packed, Programmable Current-Mode PWM ControllerThe SC4809 packs a programmable duty cycle and switching rate to 1 MHz, line-voltage monitoring, and biphase operation in an MSOP-10 package Camarillo, California - May 29, 2002 Semtech Corp. (Nasdaq: SMTC) a leading supplier of analog and mixed-signal semiconductors for communications, portable devices, computers, and industrial equipment, today announced the SC4809, a highly integrated, high-performance current-mode PWM controller geared for primary side operation. Offered in a space-saving 10-pin MSOP package, the SC4809 packs a wealth of features that tailor it for use in the latest isolated DC-DC and off-line switching power supplies. Highly efficient, the SC4809 is particularly well suited for building low-power isolated forward and flyback type switching power supplies found in telecom, networking, and industrial equipment. In particular, the SC4809 targets such cutting-edge applications as power-over-LAN for IP telephony products and broadband devices for ADSL devices and loop extenders. In a typical telecom application, the SC4809 might be used to convert an 18-Vdc to 75-Vdc bus-supply rail to 12-Vdc. The IC can also work in off-line supplies powered by AC line voltage. "Due to its high integration, which affords numerous breakthrough features normally requiring external implementation, the SC4809 is a boon to designers needing to build compact, efficient, isolated power supplies for today’s new telecom, networking, and industrial products," notes George Georgalis, Semtech’s Director of Telecom Power Management products. "By reducing the parts count, the SC4809 not only simplifies the design effort and conserves scarce circuit-board real estate, it also streamlines component procurement and end-equipment manufacturing, ultimately cutting cost." As a primary-side current-mode controller, the SC4809 contains all of the control and drive circuitry needed to build an isolated power supply using a secondary-side external error amplifier. The advantages of current-mode operation include fast response to input voltage changes, single pole compensation, inherent current limit. Especially noteworthy features of the SC4809 include its programmable switching rate up to 1 MHz, highly accurate and programmable duty cycle, line voltage monitoring with an undervoltage lockout mechanism for the supply voltage, external clock synchronization, low-ripple biphase operation, less than 100-µA start-up current, and programmable soft-start operation. Of these features, biphase operation synchronizes two controllers in a multiple-output supply so that the controllers’ clocks are 180° out of phase, minimizing input and output ripple and, as a result, reducing the required input filtering. In addition, the duty cycle, which is programmable up to 90%, offers an unmatched level of efficiency for low-power supplies. Also, once programmed, the switching frequency of the SC4809 remains fixed, a feature that simplifies EMI filtering and helps avoid frequency beating, both key goals in telecom applications. The SC4809 also includes an accessible voltage reference. The SC4809 comes in two versions: the SC4809A, having a turn-on voltage of 4.5V and the SC4809B, with a turn-on voltage of 11.5V. Both are rated for operation over a temperature range from –40° C to +105°C. Key Features
Pricing and AvailabilityProduction volumes of the SC4809 high-performance current mode PWM controller are available now through Semtech’s authorized network of direct sales representatives and distributors. Pricing starts at $0.94 each in 10,000 unit quantities. Product datasheets are available at www.semtech.com. About SemtechSemtech 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. 91320-8790; phone (805) 498-2111; email to info@semtech.com; or visit its Web site at www.semtech.com. Press ContactTerry Sears, Marketing Communications Manager, Telephone: 805.498.2111 |
