High-Efficiency Power-Supply Controller Featuring Individual ON/OFF Control Provides Five Output Voltages in Compact, Surface-Mount Package

SANTA CLARA, CALIFORNIA - April 19, 2002 - A new multi-output, power-supply controller that provides compact, power-efficient dc-dc power conversion in network equipment, telecommunications systems, and battery operated products was announced today by Siliconix incorporated (NASDAQ: SILI), an 80.4%-owned subsidiary of Vishay Intertechnology, Inc. (NYSE: VSH).

The new Si9138 works in current mode to provide tightly regulated 3.3-V and 5-V dc-to-dc converter outputs with individual ON/OFF control to help prolong battery life. Additional features include an adjustable 5-V to 12-V dc-to-dc converter output set by an external resistor divider; a precision 3.3-V reference output; and a 5-V/30-mA linear regulator output.

The new controller operates in continuous pulse width modulation (PWM) mode and offers power-saving pulse skipping mode (PSM) operation at light load. With a fixed frequency of 300 kHz, output voltage regulation is ±3% total over the full temperature, input voltage, and load-current range. Conversion efficiencies approaching 95% are achieved with synchronous rectification permitting delivery of up to 75 W of power.

Featuring a wide input voltage range of 5.5 V to 30 V, a power-good signal with delay, internal frequency compensation networks, and automatic boot-strapping, the Si9138 gives designers a versatile controller with a minimum of external control components. The controller design requires just three inductors, so no transformer is necessary. Circuit features include protection against over/under-voltage, and over-current.

Packaged in a 28-pin SSOP and specified to operate over the extended commercial temperature range of 0°C to 90°C, samples and production quantities of the Si9138 are available now, with lead times of eight weeks for larger orders.

Vishay Intertechnology, Inc., a Fortune 1,000 Company listed on the NYSE (VSH), is one of the world's largest manufacturers of discrete semiconductors (diodes, rectifiers, transistors, and optoelectronics and selected ICs) and passive electronic components (resistors, capacitors, inductors, sensors, and transducers). These components are used in virtually all types of electronic devices and equipment, in the industrial, computing, automotive, consumer, telecommunications, military, aerospace, and medical markets. Its product innovations, successful acquisition strategy, and ability to provide "one-stop shop" service have made Vishay a global industry leader. Vishay can be found on the Internet at http://www.vishay.com.