A fully integrated programmable controller IC providing dc-to-dc conversion efficiencies upwards of 93% in cell phones and other mobile communications devices was released by Vishay Siliconix. Enabling a complete dc-to-dc converter solution that requires a footprint area of just 32mm by 19mm (single sided PCB) ýthe smallest ever to provide this level of performance ý the new Si9165BQ combines conversion circuitry with on-board n- and p-channel power MOSFETs in a surface-mount TSSOP-20. With an input range of 2.7 V to 6 V, the Si9165BQ can be programmed to function either as a synchronous buck or as a boost converter, stepping current down to 1.3 V or boosting it up to 6 V.

The Si9165BQ provides power to the signal processing circuitry and power amplifiers in digital cell phones, portable phones, PDAs, and other systems powered by single-cell lithium ion batteries, and is capable of delivering up to 600 mA of output current at 3.3 V. It is the first device of its kind to operate at frequencies up to 2 MHz, which allows designers to use smaller magnetics and reduces output capacitance. When used with the new low-profile IHLP2516 inductor from Vishay Dale, a complete converter solution has a height profile of just 2 mm. The total volumetric space required for all circuitry is just 1.2 cm³, one of the smallest available for this level of performance. This combination likewise reduces the output capacitance requirement to less than 10 ýF, with peak-to-peak output ripple as low as 10 mV.

The high-frequency operation of the Si9165BQ will enable end products to be lighter, smaller, and thinner, while its high-efficiency operation will lengthen cell phone talk times and standby times. The fully-integrated p-channel high-side and n-channel low-side MOSFET switches provide low gate-charge characteristics that ensure efficient operation whether the converter is operating in PWM mode under full-load conditions or in pulse-skipping modulation (PSM) mode under light-load conditions. The programmable PSM feature maintains high efficiency even during standby and idle modes.

Additionally, a synchronization feature allows designers to set the converter to run at a defined frequency, which prevents any interference with sensitive carrier, processing, and intermediate spectrum frequencies.

"The Si9165BQ gives designers the best performance of any solution on the market in terms of efficiency, size, and synch range," said Tony Armstrong, Senior Product Marketing Manager at Vishay Siliconix. "The total number of piece parts required for a total converter is minimal, and since Vishay provides both the active and passive components, the purchaserýs task is greatly simplified."

These are not the first products from the Vishay Siliconix stable to use the combination of PWM at full load currents and pulse-skipping modulation (PSM) at low, standby, currents: But I still love it! The use of the higher 2-MHz modulation frequencies considerably simplifies the resonant circuits and Vishay is unique, I believe, in being able to supply the inductor from one of its own divisions. You certainly know that the pair have worked together to get the solution right, and the profile for the lithium-ion buck or boost circuit has got to be the lowest around. The high frequency of the PWM and its likely interference with RF services and into IFs is effectively dealt with by the use of the synchronizing feature.

Lithium-ion applications with the lower-consumption portable devices will easily be covered by the Si9165BQ and its 600-mA capability. The Si9166BQ removes the on-board n- and p-MOSFETs and allows the remaining controller-only to drive external MOSFETs. The price differential of $0.80 will not pay for two external devices, of course, so, unfortunately, there will probably be some marginal circuit designs to be seen trying to get away with the Si9165BQ in place.