Date: 15/07/2009

High frequency buck type switching regulator for WCDMA/NCDMA apps

AMS has released the new AS1339 step down regulator of high efficiency in a tiny package for multiband WCDMA/NCDMA applications. AS1339 offers 97% efficiency and it delivers up to 650mA from an input voltage range of 2.7 to 5.5V making the device ideal for single Li-Ion cells. And to improve battery lifetime the low power RF amplifiers are used to scale the output power dynamically and by changing its supply voltage and the output voltage of the AS1339 is dynamically controlled using an external analogue input signal.

Additionally, the extremely fast 30µs settling time of the output voltage ensures CDMA-specifications are not exceeded.

The 2MHz fixed switching frequency minimizes the PCB footprint by allowing the use of tiny low profile inductors and capacitors. This constant frequency switching results in low output noise which is additionally reduced by the internal noise reduction circuitry.

"Power efficiency combined with reduced external component size and cost is the key behind the AS1339 buck converter," said Bruce Ulrich, marketing director Standard Linear at austriamicrosystems." austriamicrosystems' AS1339 is the perfect symbiosis between efficiency and analog performance. Thanks to its small size and fast switching speed only a minimum of PCB space is required. Combined with the unique low noise circuitry this part is the way to go for high efficiency RF PA designs."

The AS1339 enters bypass mode automatically during high power transmissions and also integrates two 10mA low-noise, high-PSRR LDO's, which makes them ideal for PA biasing.

Other features:
Soft start and safety
Current overload and thermal shutdown protection

Package: 2x2mm WL-CSP 16-bumps.
Operational temperature range : -40°C to +85°C.
For more details visit www.austriamicrosystems.com/DC-DC-Converter/AS1339