LTC3499/LTC3499B

1

3499f

4.7

µH

3499 TA01

LTC3499

SW

FB

GND

SHDN

VC

SS

OFF

ON

10

µF

5V

175mA

1.8V TO 3.2V

1M

324k

0.01

µF

330pF

100k

2.2

µF

+

The LTC

quency step-up DC/DC power converters with integrated

reverse battery protection that protect and disconnect the

devices and load when the battery polarity is reversed while

delivering high efficiency in a small (3mm

× 3mm) DFN

package. True output disconnect eliminates inrush current

and allows zero load current in shutdown.

The devices feature an input voltage range of 1.8V to 5.5V

enabling operation from two alkaline or NiMH batteries.

The switching frequency is internally set at 1.2MHz allow-

ing the use of tiny surface mount inductors and capacitors.

A minimal number of external components are required to

generate output voltages ranging from 2V to 6V. The

LTC3499 features automatic Burst Mode operation to

increase efficiency at light loads, while the LTC3499B

features continuous switching at light loads.

The soft-start time is externally programmable through a

small capacitor. Anti-ring circuitry reduces EMI emissions

by damping the inductor in discontinuous mode. The

devices feature <1

µA shutdown supply current, integrated

overvoltage protection and are available in both 8-pin

(3mm

× 3mm) DFN and 8-pin MSOP packages.

APPLICATIO S

TYPICAL APPLICATIO

DESCRIPTIO

750mA Synchronous

Step-Up DC/DC Converters

with Reverse-Battery Protection

Two AA Cells to 5V Synchronous Boost Converter

FEATURES

and Load

× 3mm × 0.75mm) DFN

and MSOP Packages

, 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.

–6

–1.0

0

–2

2

–4

0

4

3499 TA01b

6

–0.5

1.0

0.5

SHDN = 0V