Efficient claims for step-down convertors

Edited by the Electronicstalk editorial team Dec 1, 2004

A new family of synchronous-rectification type step-down DC/DC convertors are billed as some of the most energy efficient on the market.

The XC9225/26/27 series are synchronous-rectification type step-down DC/DC convertors which draw just 15mA when in operation and have a typical efficiency of 92%, making the series one of the most energy efficient on the market.

"Battery powered devices are only useful when they work for a reasonable period on a single battery charge", according to Andy Scott of Torex Semiconductor Europe.

To meet this requirement Torex has introduced this series of synchronous step-down DC/DC convertors that provide a high efficiency, a stable power supply and output currents up to 500mA using only a coil and two capacitors connected externally.

The XC9225/26/27 is particularly suited to portable applications where power consumption and battery life are critical.

The convertors have an exceptionally low output ripple of just 10mV, and a fixed output voltage that is internally programmable in increments of 100mV in the range 0.9 to 4.0V.

In the tiny USP-6B package (2 x 1.8 x 0.8mm), the IC and companion components will fit on a board space just 6mm2.

Minimum operating voltage is 2.0V and the IC's switching frequency is selectable from 600kHz and 1.2MHz.

The XC9225 uses PWM control, the XC9226 series features automatic PWM/PFM switching control and the XC9227 series can be manually switched between the PWM and PWM/PFM switching control mode, allowing fast response, low ripple and high efficiency over the full range of load conditions.

The soft-start and current control functions are internally optimised.

During standby, all circuits are shutdown to reduce current consumption to 1.0uA or less.

The series is available in either SOT-25 or USP-6B packages.