Synchronous convertors aim for wireless designs

Edited by the Electronicstalk editorial team Nov 26, 2002

The XC9211 and XC9212 series are synchronous-rectification type DC/DC convertors with built-in 0.6ohm P-channel driver transistor and N-channel switching transistor.

The XC9211 and XC9212 series are synchronous-rectification type DC/DC convertors with built-in 0.6ohm P-channel driver transistor and N-channel switching transistor.

Highly integrated, these new step down DC/DC convertors require only the external connection of a chip inductor and two small ceramic capacitors to realise a stable power supply with an output current of 400mA.

Achieving efficiencies of up to 94% when stepping down from 3.6 to 1.8V at 100mA, the new convertors employ the very latest current/voltage multiple feedback technique providing ultra low output ripple, typically less than 10mV.

This makes the XC9211 and XC9212 particularly suited to noise sensitive radio applications such as Bluetooth and WLAN as well as a wide range of portable and handheld equipment designs.

The XC9211 provides synchronous-rectified PWM switching control.

The XC9212, on the other hand, can be manually switched between synchronous PWM control and nonsynchronous PFM/PWM using the device's CE/mode pin.

This allows fast response, low ripple output and high efficiency over a broad range of output loads.

Input voltage range is 1.8 to 6.0V.

Output voltage is internally programmable between 0.9 and 4.0V in increments of 0.1V (accuracy +/-2.0%).

The convertors' built-in oscillator gives designers a selectable oscillation frequency of 300, 600 or 900kHz, allowing them to choose the most suitable frequency for their particular application.

A 'softstart' provides the devices with protection against inrush currents when power is switched on and voltage overshoot.

On standby all circuits are shut down to reduce current consumption to less than 0.5mA.

With the built-in undervoltage lockout (UVLO) function, the internal P-channel driver transistor is forced off when input voltage reaches 1.6V or lower.

The XC9211 and XC9212 can be supplied in either SOT-25 or ultra compact USP-6B packages.