________________General Description

The MAX1672 integrates a step-up DC-DC converter with a

linear regulator to provide step-up/down voltage conver-

sion. This device provides a constant output voltage for

inputs that vary above and below the output voltage. It has

a 1.8V to 11V input range and a preset 3.3V or 5V output.

The output can also be set from 1.25V to 5.5V using two

resistors. Typical efficiency is 85%.

The MAX1672’s step-up/linear-regulator configuration per-

mits the use of a single, physically smaller inductor than

can be used with competing SEPIC and flyback configura-

tions. Switch current is also selectable, permitting the use

of smaller inductors in low-current applications. The linear

regulator also acts as a filter to reduce output ripple voltage.

The MAX1672 has a low 85µA quiescent supply current, which

is further reduced to 0.1µA in logic-controlled shutdown. The

output voltage is disconnected from the input in shutdown.

The MAX1672 also has a PGI/PGO low-battery detector.

The MAX1672 comes in a 16-pin QSOP package (same size

as a standard 8-pin SO). For a larger device that delivers more

output current, refer to the MAX710/MAX711. The preassem-

bled MAX1672 evaluation kit is available to speed designs.

________________________Applications

Single-Cell, Lithium-Powered

2-Cell to 4-Cell AA Alkaline

Portable Devices

Hand-Held Equipment

3.3V and Other Low-Voltage

Battery-Powered Devices

Systems

with AC Input Adapters

Digital Cameras

____________________________Features

o Step-Up/Down Voltage Conversion

o 1.8V to 11V Input Range

o 3.3V/5V or Adjustable Output Voltage Range

o Output Current:

≥ 2.5V)

≥ 1.8V)

o Smaller Inductor than SEPIC and Flybacks

o Load Disconnects from Input in Shutdown

o Supply Current from Battery:

85µA (No-Load)

0.1µA (Shutdown)

o PGI/

PGO Low-Battery Comparator

o 16-Pin QSOP Package

(Same Footprint as 8-pin SO)

o No External FETs Required

o Thermal and Short-Circuit Protection

Step-Up/Down DC-DC Converter

in QSOP Package

________________________________________________________________ Maxim Integrated Products

1

19-1307; Rev 2; 11/02

EVALUATION

KIT MANUAL

FOLLOWS

DATA

SHEET

Ordering Information

16

15

14

13

12

11

10

9

1

2

3

4

5

6

7

8

LX

LX

PGND

GND

REF

IN

PS

FB

OUT

TOP VIEW

MAX1672

QSOP

PGND

ONA

ILIM

PGO

PGI

3/5

ONB

Pin Configuration

MAX1672

IN

ONA

PGI

ONB

OFF

ON

PGND

GND

PS

3.3V/5V

OUTPUT

INPUT

1.8V TO 11V

LOW-BATTERY

DETECTOR

OUTPUT

OUT

PG0

FB

REF

LX

OFF

3/5

ILIM

5V

0.8A

ON

3.3V

0.5A

Typical Operating Circuit

PART

MAX1672C/D

MAX1672EEE

-40°C to +85°C

0°C to +70°C

TEMP RANGE

PIN-PACKAGE

Dice*

16 QSOP

For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at

1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.