Date: 24/11/2009

200mA DC-DC step-up converter IC with buck mode for portable device apps

Austriamicrosystems has introduced the AS1337, a new synchronous, fixed frequency, high efficiency DC-DC boost converter IC capable of supplying 3.3V at 200mA from two AA size cells. With a continuous transition between boost and regulated buck mode the AS1337 is suitable for single and dual cell, portable device applications.

The AS1337 offers automatic powersave mode to increase efficiency at light loads. For input voltages higher than VOUT, the AS1337 will switch in a step down mode and enabling buck boost functionality.

The key features of the AS1337 step-up converter are,

Operating input voltage ranges from 0.65V to 4.5V
Operating output voltage ranges from 2.5V to 5.0V
Up to 97% of efficiency
1.2MHz of high-speed fixed-frequency
Internal PMOS synchronous rectifier
Shutdown current < 1µA

The AS1337A offers a shutdown mode where the battery is connected directly to the output enabling the supply of real-time-clocks or memories. The AS1337 offers a POK (open-drain) feature, which detects output power fail of 10%.

The suggested applications for the AS1337 step-up converter include medical diagnostic equipment, hand-held instruments, pagers, digital cameras, remote wireless transmitters, MP3 players, LCD bias supplies, cordless phones, GPS receivers, and PC cards.

"Especially in dual cell applications the input voltage can be up to 3.6V when using fresh batteries. Even though this voltage is only available for a very short time, it can damage a 3V system. AS1337 enters a regulated buck mode in order to avoid this problem. A conventional boost converter does not regulate the output voltage in this case. The customer gets buck-boost behavior at the cost of a standard boost converter," commented Bruce Ulrich, Marketing Director Consumer and Communications at austriamicrosystems. "Furthermore the optimized boost architecture of the AS1337 guarantees excellent efficiencies during step-up operation of up to 97% which is significantly higher than the efficiency of a conventional buck-boost converter."

Operating temperature range: -40 to +85°C

Package: TDFN (3x3mm) 8-pin package
Availability: Now

For more details visit www.austriamicrosystems.com