austriamicrosystems AG is now ams AG The technical content of this austriamicrosystems datasheet is still valid. Contact information: Headquarters: ams AG Tobelbaderstrasse 30 8141 Unterpremstaetten, Austria Tel: +43 (0) 3136 500 0 e-Mail: ams sales ams.com Please visit our website at www.ams.com Datasheet AS1331 300mA Buck-Boost Synchronous DC/DC Converters 1 General Description 2 Key Features Input Voltage Range: 1.8V to 5.5V This special device is a synchronous buck-boost DC/DC converter which can handle input voltages above, below, Output Voltages: or equal to the output voltage. - Fixed: 2.5V, 3.0V, 3.3V - Adjustable: 2.5V to 3.3V Due to the internal structure of the AS1331 which is working continuously through all operation modes this Output Current: 300mA 3.3V device is ideal for dual or triple cell alkaline/NiCad/NiMH Up to 90% efficiency as well as single cell Li-Ion battery applications. Power Good Because of the implemented Power Save Mode, the Output Disconnection in Shutdown solution footprint and the component count is minimized and also over a wide range of load currents a high Automatic transition between Buck and Boost mode conversion efficiency is provided. Ultra Low Quiescent Current: 22A, Shutdown Cur- The device includes two N-channel MOSFET switches rent <1A (Active Low) and two P-channel switches. Also following features are Short-Circuit Protection implemented: a quiescent current of typically 22A Low Battery detection (ideal for battery power applications), a shutdown current less than 1A, current limiting, thermal shutdown Over Temperature Protection and output disconnect. 10-pin 3x3mm TDFN package The AS1331 is available in a 10-pin 3x3mm TDFN package with fixed and adjustable output voltage. 3 Applications The AS1331 is an ideal solution for handheld computers, handheld instruments, portable music players and PDAs. Two and three cell Alkaline, NiCd or NiMH or single cell Li battery powered products. Figure 1. AS1331 - Typical Application Diagram L1 6.8H SW1 SW2 4 2 1.8V to 5.5V Low Battery Detect 5 8 VIN LBO C1 R4 R3 1 10F 7 VOUT AS1331-AD 2.5V to 3.3V VOUT LBI C2 R5 R1 22F 10 6 On Off FB EN R2 3 PGND 9 GND www.austriamicrosystems.com/DC-DC Buck-Boost/AS1331 Revision 1.04 1 - 16 ams AG Technical content still valid
