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________________General Description

The MAX1673 charge-pump inverter provides a low-

cost, compact means of generating a regulated nega-

tive output from a positive input at up to 125mA. It

requires only three small capacitors, and only two resis-

tors to set its output voltage. The input range is 2V to

regulation mode.

In Skip mode, the MAX1673 regulates by varying its

switching frequency as a function of load current. This

On-Demand™ switching gives the MAX1673 two

advantages: very small capacitors and very low quies-

cent supply current. At heavy loads, it transfers energy

from the input to the output by switching at up to

350kHz. It switches more slowly at light loads, using

only 35µA quiescent supply current.

In Linear mode, the MAX1673 switches at a constant

350kHz at all loads and regulates by controlling

the current-path resistance. This provides constant-

frequency ripple, which is easily filtered for low-noise

applications.

This device also features a 1µA logic-controlled shut-

down mode and is available in a standard 8-pin SO

package. For a device that delivers about 10mA and

fits in a smaller package, refer to the MAX868.

________________________Applications

Hard Disk Drives

Measurement Instruments

Camcorders

Modems

Analog Signal-Processing

Digital Cameras

Applications

____________________________Features

o Regulated Negative Output Voltage

o 125mA Output Current

o 35µA Quiescent Supply Current

(Skip-mode regulation)

o 350kHz Fixed-Frequency, Low-Noise Output

(Linear-mode regulation)

o 2V to 5.5V Input Range

o 1µA Logic-Controlled Shutdown

Regulated, 125mA-Output,

Charge-Pump DC-DC Inverter

________________________________________________________________

Maxim Integrated Products

1

FB

OUT

SHDN

1

2

8

7

IN

GND

CAP+

CAP-

LIN/SKIP

SO

TOP VIEW

3

4

6

5

MAX1673

MAX1673

IN

INPUT 2V TO 5.5V

REGULATED

NEGATIVE

OUTPUT

UP TO 125mA)

LIN/SKIP

FB

OUT

GND

CAP+

ON

OFF

SHDN

CAP-

Typical Operating Circuit

___________________Pin Configuration

19-1334; Rev 0; 1/98

PART

MAX1673ESA

-40°C to +85°C

TEMP. RANGE

PIN-PACKAGE

8 SO

_______________Ordering Information

On-Demand™ is a trademark of Maxim Integrated Products.