Semtech's Highly Integrated, Programmable PWM Controller Vastly Eases Design of Isolated Telecom, Networking, and Industrial Power Supplies.Business Editors/High-Tech Writers
CAMARILLO, Calif.--(BUSINESS WIRE)--April 2, 2002
Programmable Voltage or Current Mode Operation, Synchronized syn·chro·nize
v. syn·chro·nized, syn·chro·niz·ing, syn·chro·niz·es
1. To occur at the same time; be simultaneous.
2. To operate in unison.
Clocking, and Up To 1-MHz Programmable Switching Frequency Give
Designers Unprecedented Benefits
Semtech Corp. (Nasdaq:SMTC SMTC Southern Maine Technical College
SMTC Science/Mathematics/Technology Center (Central Michigan University)
SMTC Saluda Mountain Telephone Company (Knoxville, Tennessee)
SMTC Short-To-Medium Term Control ) 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 (Pulse Width Modulation) A modulation technique that generates variable-width pulses to represent the amplitude of an analog input signal. Like its fixed-width pulse density modulation (PDM) cousin, the output switching transistor is on more of the time for a 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 (1) A device that changes one set of codes, modes, sequences or frequencies to a different set. See A/D converter.
(2) A device that changes current from 60Hz to 50Hz and vice versa. 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 Clock synchronization is a problem from computer science and engineering which deals with the idea that internal clocks of several computers may differ. Even when initially set accurately, real clocks will differ after some amount of time due to clock drift, caused by clocks , are aimed at benefiting designers while streamlining procurement The fancy word for "purchasing." The procurement department within an organization manages all the major purchases. 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 IC 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-degrees 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 resistor, two-terminal electric circuit component that offers opposition to an electric current. Resistors are normally designed and operated so that, with varying levels of current, variations of their resistance values are negligible (see resistance). , that can be programmed to 1 MHz (MegaHertZ) One million cycles per second. It is used to measure the transmission speed of electronic devices, including channels, buses and the computer's internal clock. A one-megahertz clock (1 MHz) means some number of bits (16, 32, 64, etc. and externally synchronized; a dual-output drive stage in push-pull configuration For other uses of "push-pull", see Push-pull.
An aircraft constructed with a push-pull configuration has a mixture of forward-mounted (tractor) propellers and backward-mounted (pusher) propellers.
An early example of a "push-pull" aircraft was the Caproni Ca. ; soft start-up operation with a 120-uA start-up current; cycle-by-cycle current limiting Current limiting is the practice in electrical or electronic circuits of imposing an upper limit on the current that may be delivered to a load with the purpose of protecting the circuit generating or transmitting the current from harmful effects due to a short-circuit or similar ; and programmable line-undervoltage lock out (LUVLO) with hysteresis hysteresis (hĭs'tərē`sĭs), phenomenon in which the response of a physical system to an external influence depends not only on the present magnitude of that influence but also on the previous history of the system. .
-- 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-uA 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 to +105 degrees C, and is available now from Semtech's authorized au·thor·ize
tr.v. au·thor·ized, au·thor·iz·ing, au·thor·iz·es
1. To grant authority or power to.
2. To give permission for; sanction: network of sales representatives and distributors. Pricing starts at $1.30 each in production quantities of 1,000 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.
Semtech Corp. 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 firstname.lastname@example.org; or visit its Web site at www.semtech.com.
Note to Editors:
A "u" represents the micron micron: see micrometer.
One micrometer, which is one millionth of a meter or approximately 1/25,000 of an inch. The tiny elements that make up a transistor on a chip are measured in micrometers and nanometers. See process technology. symbol when used as part of "uA" throughout this release... in "(operation with a 120-uA start-up)," and "(Soft start-up with 120uA current)."