austriamicrosystems : Buck regulator features two LDOs for RF PAs

Austriamicrosystems introduces the AS1339 step down regulator. High efficiency and tiny packaging make the AS1339 ideal for multiband WCDMA/NCDMA applications, such as cellular handsets, wireless PDAs, and smart phones.

The AS1339 delivers up to 650mA from an input voltage range of 2.7 to 5.5V making the device ideal for single Li-Ion cells. To improve battery lifetime low power RF amplifiers can scale the output power dynamically by changing its supply voltage. To support this, 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 AS1339 housed in a 2x2mm WL-CSP is designed for minimal space requirements in size restricted battery powered applications such as mobile phones and other portable wireless end equipment. 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 predictable 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.”

With 97% peak efficiency the AS1339 boosts battery lifetime in any application. Supporting 1.1A of peak current, the integrated 110m Ohm bypass FET provides maximum power with minimum dropout under even low-battery conditions. The AS1339 enters bypass mode automatically during high power transmissions. The AS1339 also integrates two 10mA low-noise, high-PSRR LDO’s, making them ideal for PA biasing. Each LDO features a separate enable, provides high output voltage accuracy, and requires only 10nF of output capacitance.


Moreover if the supply is not required, for example mobile phone in-flight mode, the AS1339 offers a 100nA shutdown mode combined with an output disconnect feature. Additional features are soft start and safety features such as current overload and thermal shutdown protection.
The AS1339 is available in the tiny 2x2mm WL-CSP 16-bumps covering the industrial temperature range of -40°C to +85°C. For product specific information, to download data sheets or to request free samples from austriamicrosystems’ online shop ICdirect, please visit

About austriamicrosystems

austriamicrosystems is a leading designer and manufacturer of high performance analog ICs, combining more than 27 years of analog design capabilities and system know-how with its own state-of-the-art manufacturing and test facilities. austriamicrosystems leverages its expertise in low power and high accuracy to provide industry-leading customized and standard analog products. Operating worldwide with more than 1,000 employees, austriamicrosystems focuses on the areas of power management, sensors & sensor interfaces and mobile infotainment in its markets Communications, Industry & Medical and Automotive, complemented by its Full Service Foundry activities. austriamicrosystems is listed on the SIX Swiss Exchange in Zurich (ticker symbol: AMS).

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Note: The above text is the public part of the press release obtained from the manufacturer (with minor modifications). EETimes Europe cannot be held responsible for the claims and statements made by the manufacturer. The text is intended as a supplement to the new product presentations in EETimes Europe magazine.

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