Semtech's 1MHz, Dual-Ended PWM Controller Provides Design Flexibility in Off-Line and Isolated Telecom DC-to-DC Converters.CAMARILLO, Calif. -- Multi-function SC4806 can be configured in current or voltage mode, with programmable UVLO UVLO Undervoltage Lockout UVLO Under Voltage Lock Out , and can be implemented in push-pull, half-bridge or full-bridge designs 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, portable devices, computers, and industrial equipment, today announced the SC4806, a dual-ended, pulse-width modulation Pulse-width modulation (PWM) of a signal or powersource involves the modulation of its duty cycle, to either convey information over a communications channel or control the amount of power sent to a load. (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 that features low power consumption and high speed that makes it ideal for designing compact high power isolated off-line and telecom power supplies. The SC4806 has very low 90uA start-up current and can be configured in either current mode or voltage mode. The controller can operate in peak current mode or in voltage mode by programming the slope compensation using a single external resistor. Operating in voltage mode feed forward allows fast line transient response In electrical engineering and Mechanical Engineering, a transient response or natural response is the response of a system to a change from equilibrium. Specifically, transient response in Mechanical Engineering is the portion of the response that approaches zero after a and eliminates the need for current sensing elements. The current mode control simplifies the loop dynamics and reduces transformer saturation problems in full-bridge and push-pull topologies. The SC4806 contains all of the control circuitry required for isolated applications where a secondary side error amplifier is used. Operating from Telecom Power rails (36V to 76V), the SC4806 can be used to design highly efficient, high current push-pull, half-bridge or full-bridge isolated power converters. The SC4806 can be programmed using an external RC circuit 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. operating frequency. The two outputs operate 180-degrees out-of-phase and run at half the frequency. The controller also features SYNC that allows the oscillator oscillator Mechanical or electronic device that produces a back-and-forth periodic motion. A pendulum is a simple mechanical oscillator that swings with a constant amplitude, requiring the addition of energy at each swing only to compensate for the energy lost because of air to synchronize See synchronization. its clock to an external source. The SC4806 utilizes a unique oscillator that allows two SC4806 devices to be synchronized to provide automatic out-of-phase (bi-phase) switching, minimizing input and output current ripple and reducing the stress on, and size of input/output filter components. The SC4806 features two levels of under voltage lock out (UVLO) programmable through an external resistor divider divider See European currency quotation. . An additional programmable soft start feature allows for a controlled system start-up. "The SC4806 is the ultimate versatile PWM controller," said Ven Shan, Vice President of Marketing for Semtech's Power Management Products. "The feature set is augmented by a small package size, high operating frequency and high integration that can deliver high power density to isolated DC to DC converter In electronic engineering, a DC to DC converter is a circuit which converts a source of direct current (DC) from one voltage level to another. It is a class of power converter. designs for the networking, telecom and server markets." The SC4806 has built-in pulse-by-pulse 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 auto-restart over-current protection in both current and voltage modes. Each SC4806 has a two channel half-bridge power circuit, with the flexibility to combine two devices in a full bridge design for systems needing up to 1,000 Watts of power. This capability comes with programmable dead time between the two outputs that can be adjusted depending on the size of the timing components. The turn-on threshold of this device is 7.9V typically, matching the common bias voltage See bias. for synchronous-rectifier drives. The SC4806 extends Semtech's SC4800-series family of dual-ended PWM power controllers. The part is packaged in a small MLPQ-12 package that is lead-free, and complies with the European Union's Restriction on Hazardous Substances in Electrical and Electronic Equipment (RoHS) directive to meet worldwide environmental and regulatory requirements. Key Features of the SC4806 --90uA starting current --Unique oscillator allows two SC4806 to be synchronized for bi-phase interleaving interleaving - sector interleave operation --Pulse-by-pulse and auto-restart over-current protection for both voltage/current modes --Programmable operating frequency up to 1 MHz --Programmable external soft start --Lead free, 4 x 4 mm MLPQ-12 package; WEEE/RoHS compliant ---40 degrees to 105 degrees operating temperature Pricing and Availability The SC4806 is available immediately in production quantities and is priced at $1.50 each in 1,000-piece lots. The order code for the device is SC4806MLTRT. 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. |
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