LTC3109

1

3109fa

TYPICAL APPLICATION

FEATURES

DESCRIPTION

Auto-Polarity, Ultralow

Voltage Step-Up Converter

and Power Manager

for harvesting surplus energy from extremely low input

voltage sources such as TEGs (thermoelectric genera-

tors) and thermopiles. Its unique, proprietary autopolarity

topology* allows it to operate from input voltages as low

as 30mV, regardless of polarity.

Using two compact step-up transformers and external

energy storage elements, the LTC3109 provides a com-

plete power management solution for wireless sensing

and data acquisition. The 2.2V LDO can power an external

microprocessor, while the main output can be programmed

to one of four fixed voltages. The power good indicator

signals that the main output is within regulation. A second

output can be enabled by the host. A storage capacitor (or

battery) can also be charged to provide power when the

input voltage source is unavailable. Extremely low quies-

cent current and high efficiency maximizes the harvested

energy available for the application.

The LTC3109 is available in a small, thermally enhanced

20-lead (4mm × 4mm) QFN package and a 20-lead SSOP

package.

APPLICATIONS

Energy

System

– 2.2V, 5mA LDO

– Logic-Controlled Output

– Energy Storage Capability for Operation During

Power Interruption

20-Lead SSOP

L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear

Technology Corporation. All other trademarks are the property of their respective owners.

*Patent pending.

GND

1μF

5.25V

2.2V

LTC3109

3.3V

3109 TA01a

C1A

1nF

2.2μF

470pF

47μF

1nF

470pF

1:100

TEG

(THERMOELECTRIC GENERATOR)

±30mV TO ±500mV

••

1:100

••

C2A

C1B

C2B

SWB

VS1

VS2

SWA

VLDO

PG00D

VSTORE

VAUX

VAUX

+

470μF

OPTIONAL SWITCHED OUTPUT FOR SENSORS

+

μP

LOW POWER

RADIO

SENSOR(S)

–300

0

100

300

400

500

100

900

3109 TA01b

200

–100

–200

200

0300

600

700

800

1:100 TRANSFORMERS

C1A = C1B = 1nF