FEATURES

Runs on 3.3- or 5-V Supplies

Adjustable, High Precision Output

Voltage

High Frequency Operation (>1 MHz)

High Efficiency Synchronous

Switching

Full Set of Protection Circuitry

2000-V ESD Rating (Si9140CQ/DQ)

DESCRIPTION

Siliconix’ Si9140 Buck converter IC is a high-performance,

surface-mount switchmode controller made to power the new

generation of low-voltage, high-performance microprocessors.

The Si9140 has an input voltage range of 3 to

6.5 V to simplify power supply designs in desktop PCs. Its

high-frequency switching capability and wide bandwidth

feedback loop provide tight, absolute static and transient load

regulation. Circuits using the Si9140 can be implemented with

low-profile, inexpensive inductors, and will dramatically

minimize power supply output and processor decoupling

capacitance. The Si9140 is designed to meet the stringent

regulation requirements of new and future high-frequency

microprocessors, while improving the overall efficiency in new

“green” systems.

Today’s state-of-the-art microprocessors run at frequencies

over 100 MHz. Processor clock speeds are going up and so

are current requirements, but operating voltages are going

down. These simultaneous changes have made dedicated,

high-frequency, point-of-use buck converters an essential part

of any system design. These point-of-use converters must

operate at higher frequencies and provide wider feedback

bandwidths than existing converters, which typically operate

at less than 250 kHz and have feedback bandwidths of less

than 50 kHz. The Si9140’s 100-kHz feedback loop bandwidth

ensures a minimum improvement of one-half the required

output/decoupling capacitance, resulting in a tremendous

reduction in board size and cost of implementation.

With the microprocessing power of any PC representing an

investment of hundreds of dollars, designers need to ensure

that the reliable operation of the processor will not be affected

by the power supply. The Si9140 provides this assurance. A

demo board, the Si9140DB, is available.

Si9140CQ-T1 and Si9140DQ-T1 are available in lead free.