Micropower High Efficiency 3.3/5V Step-Up DC/DC Converter

The LT1300 is a micropower step-up DC/DC converter that utilizes Burst Mode™ operation. The device can deliver 5V or 3.3V from a two-cell battery input. It features programmable 5V or 3.3V output via a logic-controlled input, no-load quiescent current of 120µA and a shutdown pin which reduces supply current to 10µA. The on-chip power switch has a low 170mV saturation voltage at a switch current of 1A, a four-fold reduction over prior designs. A 155kHz internal oscillator allows the use of extremely small surface mount inductors and capacitors. Operation is guaranteed at 1.8V input. This allows more energy to be extracted from the battery increasing operating life. The ILIM pin can be used to program peak switch current with a single resistor allowing the use of less expensive and smaller inductors and capacitors in lighter load applications. The LT1300 is available in an 8-lead SOIC package, minimizing board space requirements. For a 5V/12V Selectable Output Converter see the LT1301. For increased output current see the LT1302.

Applications

* Palmtop Computers

* Portable Instruments

* Bar-Code Scanners

* DC/DC Converter Module Replacements

* Battery Backup Supplies

* Personal Digital Assistants

* PCMCIA Cards

* Up to 220mA Output Current at 5V from 2V Supply

* Supply Voltage as Low as 1.8V

* Up to 88% Efficiency

* Small Inductor –10µH

* 120µA Quiescent Current

* Shutdown to 10µA

* Programmable 3.3V or 5V Output

* ILIM Pin Programs Peak Switch Current

* Low VCESAT Switch: 170mV at 1A Typical

* Uses Inexpensive Surface Mount Inductors

* 8-Lead DIP or SOIC Package