Microsemi

Microsemi Integrated Products

11861 Western Avenue, Garden Grove, CA. 92841, 714-898-8121, Fax: 714-893-2570

Page 1

Copyright

© 2002

Rev. 3.0a, 2005-03-14

LX1734

1.0MHz Inverting DC/DC Converter

TM

®

DESCRI PTI O N

The LX1734 is an inverting

DC/DC current-mode controller. With

a 750mA integrated switch, the

LX1734 can generate large output

currents in a small footprint.

The

LX1734 minimizes external com-

ponent size and cost by implementing

a

high

switching

frequency

of

1.0MHz, while generating -5V at

250mA.

When configured in the dual

inductor inverting topology very low

output voltage ripple approaching

conjunction

with

ceramic

output

capacitors. The dual inductor can be

implemented as a coupled or separate

cores.

Fixed frequency operation ensures a

clean output free from low frequency

noise typically present with charge pump

solutions. The low impedance output

remains within 1% of nominal during

large load steps. The 18V switch allows

high voltage outputs to be generated.

The LX1734 is available in the space

saving

6-lead

3x3

Jedec

MO-229

package, which has the same footprint

and lead spacing as the SOT-23A. A

complete inverter function utilizes less

IMPORTANT:

For the most current data, consult MICROSEMI’s website: http://www.microsemi.com

KEY FEATUR ES

Fixed Frequency 1.0MHz

Operation

Ripple Possible With Cuk

Topology

Stable Operation With Ceramic or

Tantalum Capacitors

-5V at 250mA from 5V Input

Uses Small Surface Mount L/C

Components

Wide Input Range: 4.2V to 8V

Low VCESAT Switch: 600mV at

600mA

6-Lead 3x3mm JEDEC MLPM

Package

Functionally Compatible with

LT1611 or LT1931

APPLICATIONS/BENEFITS

Disk Drive MR Head Bias

Digital Camera CCD Bias

LCD Bias

GaAs FET Bias

Local -5V or -12V Supplies

PRODUCT H I GHLIGHT

C1

10

µF

V

LX1734

V

IN

SW

L1A

22

µH

GND

NFB

C2

1

µF

R2

10k

R1

29.4k

L1B

22

µH

C3

22

µF

V

@ 150mA

C4

1000pF

Note: L1A and L1B are shown as coupled. Individual inductors can also be used.

C1, C2, C3 are ceramic capacitors

SD

Figure 1

PACKAGE ORDER INFO

LM

Plastic MLPL

6-Pin

°C)

RoHS Compliant / Pb-free

Transition DC: 0452

0 to 85

LX1734CLM

Note: Available in Tape & Reel. Append the letters “TR” to the

part number. (i.e. LX1734CLM-TR)