austriamicrosystems Intros Low Noise 650mA DC-DC Buck Regulators

(Product News, 1 Apr 2009)

Austriamicrosystems has launched the AS1332-34 family of step down DC-DC regulators optimized for noise sensitive RF power amplifiers in single cell Li-Ion battery powered applications. The three devices in the AS1332-34 family deliver up to 650mA from an input voltage range of 2.7 to 5.5V making the devices ideal for single Li-Ion cells. The AS1332 is optimized for low power RF amplifiers where the output power is scaled by the supply voltage to improve battery lifetime. An external analog reference voltage is applied to the Vcon input, upon which the output voltage follows the reference voltage within a period of 20µs (multiplied by an internal gain of 2.5), varying the output between 1.3 to 3.16V. This fast rise and fall time ensures plenty of operational margin. The output voltage of the AS1333 is fixed at 3.09V whereas the AS1334 is available in 1.2, 1.5, 1.8, 2.5, 3.0 and 3.3V output voltage versions.

The AS1332-34 family is designed for minimal space requirements in size-restricted battery-powered applications and is ideal for mobile phones and other portable wireless end equipment. The 2MHz fixed switching frequency minimizes PCB footprint by allowing the use of tiny, low profile inductors and capacitors. This constant frequency switching, together with internal noise reduction circuitry, results in an output voltage ripple of less than 2mV peak-to-peak. With 97% peak and 94% average efficiency the new buck converter family boosts battery lifetime in any application. Moreover, if no supply is required, for example in mobile phone in-flight mode, the AS1332-34 offers a shutdown mode requiring only 100nA current combined with an output disconnect feature. Additional features such as soft start and power-ok are available on the AS1334. Safety features include current overload and thermal shutdown protection.