400mA Micropower Synchronous Step-Up DC/DC Converter with Pass Through Mode

The LTC3525D-3.3 is a high efficiency synchronous stepup DC/DC converter that can start up with an input as low as 0.85V. It offers 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 LTC3525D features a fixed output voltage of 3.3V. In shutdown, VOUT is connected to VIN through the inductor.

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 anti-ringing control and thermal shutdown. The LTC3525D 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

* VOUT Connected to VIN in Shutdown

* Up to 95% Efficiency

* 0.85V Minimum Input Start-Up Voltage

* Fixed Output Voltage of 3.3V

* Delivers 60mA at 3.3V from a 1V Input, or 140mA at 3.3V from a 1.8V Input

* Burst Mode® Operation: IQ = 7μA

* VIN Range: 0.5V to 4.5V