1

LT3473/LT3473A

3473f

Conversion Efficiency and Power Loss vs Output Current

Micropower 1A Boost

Converter with Schottky

and Output Disconnect

No Load)

1µA in Shutdown Mode

Bias Voltages (LT3473A)

FEATURES

DESCRIPTIO

APPLICATIO S

TYPICAL APPLICATIO

The LT

converters with integrated Schottky diode and output

disconnect circuitry in low profile DFN packages. The

small package size, high level of integration and the use of

tiny SMT components yield a solution size of less than

25V at up to 80mA from a Li-Ion cell, while automatic Burst

Mode operation maintains efficiency at light load. An

auxiliary reference input (CTRL) allows the user to over-

ride the internal 1.25V feedback reference with any lower

value, allowing full control of the output voltage during

operation. A PGOOD pin sinks current when the output

voltage reaches 90% of final value.

The LT3473A includes two NPN transistors for generating

intermediate bias voltages from the output and is offered

in a 12-lead (4mm × 3mm) DFN package. The LT3473

does not include these NPNs and is offered in an 8-lead

(3mm × 3mm) package.

The rugged 36V switch and output disconnect circuitry

allow outputs up to 34V to be easily generated in a simple

boost topology.

2.2µF

25V

80mA

3473 TA01a

4.7µF

0.47µF

3V TO 4.2V

2M

100k

LT3473

GND

6.8µH

PGOOD

CTRL

SW

SHDN

OUT

CAP

FB

, LTC and LT are registered trademarks of Linear Technology Corporation.

Burst Mode is a registered trademark of Linear Technology Corporation.

All other trademarks are the property of their respective owners.

OUTPUT CURRENT (mA)

0.1

65

70

3473 TA01b

60

55

1

10

100

80

200

100

400

300

0

500

75