400mA Micropower Synchronous Step-Up DC/DC Converter with Output Disconnect

The LTC3525-3/LTC3525-3.3/LTC3525-5 are high efficiency synchronous step-up DC/DC converters with output disconnect that can start up with an input as low as 0.85V. They offer a compact, high efficiency alternative to charge pumps in single cell or dual cell alkaline or Li-Ion applications. Only three small external components are required. The LTC3525 is offered in fixed output voltages of 3V, 3.3V or 5V.

The device includes a 0.5Ω N-channel MOSFET switch and a 0.8Ω P-channel synchronous rectifier. Peak switch current ranges from 150mA to 400mA, depending on load, providing enhanced efficiency. Quiescent current is an ultralow 7μA, maximizing battery life in portable applications.

Other features include <1μA shutdown current, antiringing control and thermal shutdown. The LTC3525 is available in a tiny 6-Lead SC70 package.

List of LTC3525 Options

PART NAME

INPUT START-UP VOLTAGE

OUTPUT VOLTAGE

VOUT STATUS IN SHUTDOWN MODE

LTC3525-3

0.85V

3V

Output Disconnect

LTC3525-3.3

0.85V

3.3V

Output Disconnect

LTC3525-5

0.85V

5V

Output Disconnect

LTC3525D-3.3

0.85V

3.3V

Pass Through Mode

LTC3525L-3

0.7V

3V

Output Disconnect

Applications

* MP3 Players

* Portable Instruments

* Glucose Meters

* Digital Cameras

* Up to 95% Efficiency* Output Disconnect and Inrush Current Limit* Fixed Output Voltages of 3V, 3.3V or 5V* Delivers 65mA at 3V from a 1V Input* Delivers 60mA at 3.3V from a 1V Input, or 140mA at 3.3V from a 1.8V Input* Delivers 175mA at 5V from a 3V Input* Burst Mode® Operation: IQ = 7μA