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 AS1337 200mA, DC-DC Step-Up Converter with Buck Mode 1 General Description 2 Key Features Input Voltage Range: 0.65V to 4.5V The AS1337 is a synchronous, fixed frequency, highefficiency DC-DC boost converter capable of supplying 3.3V 200mA Low Start-Up Voltage: 0.85V from two AA Cells. Compact size and minimum external parts Output Voltage Range: 2.5V to 5.0V requirements make these devices perfect for modern portable devices. The AS1337 offers automatic powersave mode to Delivers 200mA 3.3V (from two AA Cell) increase efficiency at light loads. For input voltages higher up to 97% Efficiency than VOUT the AS1337 will switch in a step down mode, so that a Buck Boost function is realized. High-Speed Fixed-Frequency: 1.2MHz The AS1337A offers a shutdown mode where the battery is Single-Cell Operation connected directly to the output enabling the supply of real- Internal PMOS Synchronous Rectifier time-clocks or memories. In the shutdown mode of the AS1337B the battery is discon- Automatic Powersave Operation nected and the output is discharged. Anti-Ringing Control Minimizes EMI Table 1. Standard Products Logic Controlled Shutdown (< 1A) Model Operation Mode TDFN (3x3mm) 8-pin Package AS1337A Battery Connected in Shutdown Battery Disconnected in Shutdown and AS1337B Output Discharged 3 Applications The AS1337 offers a POK (open-drain) feature which detects The AS1337 is ideal for low-power applications where ultra- output power fail of 10%. small size is critical as in medical diagnostic equipment, hand- The AS1337 is available in a TDFN (3x3mm) 8-pin package. held instruments, pagers, digital cameras, remote wireless transmitters, MP3 players, LCD bias supplies, cordless phones, GPS receivers, and PC cards. Figure 1. AS1337 - Typical Application Diagram Dual Cell to 3.3V Synchronous Boost Converter 3.6V L1 4.7H VOUT = 3.3V Buck Mode VOUT VIN = 2xAA LX C OUT V =3.3V OUT 1.6V to 3.6V 22F VIN FB C IN V Curve IN AS1337 10F On Boost Mode Off EN POK GND PGND 1.6V www.austriamicrosystems.com/DC-DC Step-Up/AS1337 Revision 1.05 1 - 15 ams AG Technical content still valid 2x AA Cell Range