General Description

The MAX1744/MAX1745 are step-down DC-DC con-

trollers capable of handling up to 36V inputs. These

parts use a proprietary current-limited control scheme

for excellent light- and full-load efficiency, while their

330kHz (max) switching frequency permits small exter-

nal components for space-critical applications.

Operation to 100% duty cycle permits the lowest possi-

ble dropout voltage.

The MAX1744 contains an internal feedback network

that provides a pin-selectable output voltage of either

3.3V or 5V. The MAX1745 uses an external feedback

network to generate an adjustable output voltage

between 1.25V and 18V.

The MAX1744/MAX1745 are available in a space-sav-

________________________Applications

Automotive Electronics

Telecom Systems

Wall-Cube-Powered Devices

Industrial Control Systems

____________________________Features

♦ High-Voltage Operation (Up to 36V IN)

♦ Efficiency > 90%

♦ Output Power Capability Exceeds 50W

♦ 10-Pin µMax Package

♦ Low-Dropout Voltage

♦ 100% (max) Duty Cycle

♦ 90µA Quiescent Current

♦ 4µA Shutdown Current

♦ Up to 330kHz Switching Frequency

♦ Output Voltage

5V or 3.3V (MAX1744)

Adjustable 1.25V to 18V (MAX1745)

♦ Current-Limited Control Scheme

High-Voltage, Step-Down DC-DC

Controllers in µMAX

________________________________________________________________

Maxim Integrated Products

1

19-1776; Rev 4; 8/09

Ordering Information

PART

TEMP RANGE

PIN-PACKAGE

MAX1744EUB+

-40

°C to +85°C

10 μMAX

MAX1744AUB+

-40

°C to +125°C

10 μMAX

MAX1744EUB/V+

-40

°C to +85°C

10 μMAX

MAX1745EUB+

-40

°C to +85°C

10 μMAX

MAX1745AUB+

-40

°C to +125°C

10 μMAX

MAX1745EUB/V+

-40

°C to +85°C

10 μMAX

GND

OUT

REF

VL

CS

MAX1744

3/5

5V

3.3V

ON

OFF

SHDN

IN

VH

EXT

P

IN

4.5V TO 36V

OUT

3.3V

OR 5V

Typical Operating Circuit

1

+

2

3

4

5

10

9

8

7

6

IN

EXT

VH

3/5 (FB)

( ) ARE FOR MAX1745 ONLY.

REF

VL

GND

MAX1744

MAX1745

μMAX

TOP VIEW

CS

OUT

SHDN

Pin Configuration

For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,

or visit Maxim's website at www.maxim-ic.com.

EVALUATION

KIT

AVAILABLE

μMAX is a registered trademark of Maxim Integrated Products, Inc.

Firewire is a registered trademark of Apple, Inc.

IEEE is a registered service mark of the Institute of Electrical

and Electronics Engineers, Inc.

+

Denotes a lead(Pb)-free/RoHS-compliant package.

/V Denotes an automotive qualified part.