austriamicrosystems AG (austriamicrosystems) has launched an ultrasmall inductorless DC-DC boost converter, the AS1302. The AS1302 is capable of output currents as high as 30mA from a wide ranging input of 2.9 to 5.15V. The new AS1302 offers low-noise constant frequency operation from light to higher loads. Its unique constant-frequency architecture provides both low input and low output ripple and its high 1.2MHz switching frequency allows the use of extremely small external capacitors.
To improve efficiency the frequency is reduced to 49kHz during light loads. The AS1302 requires only two =220nF flying caps and two =2.2µF bypass capacitors. Combined with the small size of the WL-CSP-8 package, this creates an extremely compact solution for space-constrained applications.
Providing a regulated output, the AS1302 is ideally suited for a variety of applications such as 2-3 AA cells alkaline/NiMH or 1 cell Li-Ion battery to 5V boost conversion in portable devices. With an excellent efficiency of up to 99% in 1:1 mode and up to 90% in 1:2 or 2:3 mode the AS1302 offers lowest quiescent current and features a 10nA shutdown mode in which the output is fully disconnected from the input.
Inductorless DC-DC converters like the AS1302 are often the ideal solution for extremely space restricted applications requiring high efficiency, commented Walter Moshammer, marketing director standard linear at austriamicrosystems. They require only small capacitors and have no need for bigger inductors to generate the desired voltage which has the additional advantage of no electromagnetic emissions influencing the application.
To prevent excessive inrush current during startup, the AS1302 offers a soft-start feature plus additional features like overload protection and thermal shutdown circuitry. The AS1302 is available in a 1.2×1.2mm WL-CSP 8-bump package and is suitable for operating environments ranging from -40 to +85°C.