Nov 29, 2005 
The high-voltage SiP12201 and low-voltage SiP12202 controllers both are designed to enable flexible, efficient voltage conversion in a broad range of applications in battery-powered, telecom, and industrial end systems. The new devices' synchronous buck architecture allows voltages to be converted with efficiencies of 93%, prolonging battery life while lowering heat in enclosed field-mounted or rack-mounted systems and reducing the need for cooling systems.
The input voltage range is 4.2 V to 26 V for the SiP12201 and 2.7 to 5.5 V for the SiP12202. Adjustable output voltages for the two devices range from 0.6 V to 20 V for the SiP12201 and from 0.6 V to 5.5 V for the SiP12202. The ability to reach 0.6 V at the low end is a unique capability for a device with a 500-kHz operating frequency and ensures the SiP12201 and SiP12202 will be able to satisfy the future requirements of lower voltages, predicted to decrease to 0.6 V during the next decade.
SiP12201 High-Voltage Step-Down Controller
The high-voltage SiP12201 synchronous buck step-down controller is designed for industrial controls, wireless and cable modems, set-top boxes, LCD TVs, telecom power supplies and servers, point-of-load (POL) modules, and for delivering regulated power to microprocessors, ASICs, FPGAs, and DSPs in a wide variety of end products. Able to drive n-channel MOSFETs for both the high side and low side in a synchronous converter, the SiP12201 helps to reduce overall design costs by allowing the use of two lower-cost n-channel devices instead of one n-channel and one p-channel device. The SiP12201 also offers the advantage of 500-kHz operation, which allows the use of smaller passive components in converter designs.
SiP12202 Low-Voltage Step-Down Controller
The low-voltage SiP12202 synchronous buck step-down controller is intended for power conversion in battery-powered electronics, as well as in notebook and desktop computers and a wide range of other systems using point-of-load or distributed power converters. The controller can be set to 100% duty cycle to assure continued efficiency during low input-voltage conditions. In the event of a low-battery condition, the chip is able to operate as a low dropout (LDO) regulator by going to 100% duty cycle.
The SiP12202 drives an n-channel MOSFET on the low side and a p-channel MOSFET on the high side. Use of the p-channel MOSFET on the high side eliminates the need for an external charge pump while also simplifying the high-side gate driver. High-frequency operation up to 500 kHz enables use of smaller passive components for more compact end systems.
Because Vishay provides compatible controller and MOSFET devices, designers have access to the best complete solutions for high- and low-voltage step-down applications. The SiP12201 is optimized for use with Vishay's Si7114DN n-channel power MOSFETs, while the SiP12202 is optimized for use with the Si7106DN p-channel and Si7110DN n-channel power MOSFETs.
Both of the new step-down controllers include a combination compensation/shutdown pin, as well as additional protection features such as undervoltage lockout, power good output, output-current limit, and thermal shutdown. Internal soft start prevents voltage spikes during startup. Each controller is available in a lead (Pb)-free MLP33-10 package and is specified to operate over a temperature range of -40 to +85 degrees Celsius.
Samples and production quantities of the new synchronous buck step-down controller ICs are available now, with lead times of six to seven weeks for larger orders. Pricing for U.S. delivery in 1,000-piece quantities is $0.82 for the SiP12201 and $0.80 for the SiP12202.
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, and transducers). Vishay's components can be found in products manufactured in a very broad range of industries worldwide. Vishay is headquartered in Malvern, Pa., and has operations in 17 countries employing over 25,000 people. Vishay can be found on the Internet at http://www.vishay.com.
Editor resources:
Links to product datasheets:
http://www.vishay.com/doc?73541 (SiP12201)
http://www.vishay.com/doc?73542 (SiP12202)
Link to product summary table:
http://www.wallstcom.com/vishay/051128.htm
Link to product photo:
http://www.wallstcom.com/vishay/sip12201.zip
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