New Industry Products

Siliconix Debuts New Si9138 Power Supply Controller

April 07, 2002 by Jeff Shepard

Siliconix Inc. (Santa Clara, CA), a subsidiary of Vishay Intertechnology Inc. (Malvern, PA), announced its new Si9138 multi-output, power-supply controller that provides compact, power-efficient, dc/dc power conversion in network equipment, telecommunications systems and battery-operated products. The Si9138 works in current mode to provide tightly regulated 3.3V and 5V dc/dc converter outputs with individual on/off control to help prolong battery life.

The Si9138 features an adjustable 5V to 12V dc/dc converter output set by an external resistor divider; a precision 3.3V reference output; a 5V/30mA linear regulator output; a fixed frequency of 300kHz; an output-voltage regulation of ±3 percent total over the full temperature, input-voltage and load-current range; a conversion efficiency approaching 95 percent; a wide input-voltage range of 5.5V to 30V; a power-good signal with delay; internal frequency compensation networks; and automatic boot-strapping.

The new controller operates in continuous pulse-width-modulation mode and offers power-saving pulse-skipping-mode operation at light load. The controller design requires just three inductors, so no transformer is necessary. Circuit features include protection against over-voltage, under-voltage and over-current.

Packaged in a 28-pin SSOP and specified to operate over the extended commercial temperature range of 0 to 90 degrees C, samples and production quantities of the Si9138 are available now, with lead times of eight weeks for larger orders. Pricing for US delivery in 50,000-piece quantities is $2.20.