General Description

The MAX1947 is a compact, high-efficiency, step-up DC-

DC converter that regulates output voltages from 1.8V to

3.3V to power µP/DSP cores, memory, and I/O rails in 1-

and 2-cell alkaline/NiMH/NiCd battery-powered systems.

It features an internal 800mA switch and synchronous

rectifier to achieve up to 94% efficiency and to eliminate

the need for an external Schottky diode.

High-frequency switching (up to 2MHz) results in low

ripple and small external components, while automatic

pulse skipping at light loads reduces supply current to

just 70µA for extended battery life. Maxim’s proprietary

True Shutdown™ reduces supply current to just 2µA

and fully discharges the output to ground. The convert-

er is offered in fixed-output voltages of 1.8V, 2.5V, 3.0V,

and 3.3V, requiring no feedback or compensation net-

work. A 75ms RESET output flag provides for power-on

reset (POR) and undervoltage detection. The MAX1947

is available in a space-saving 8-pin TDFN package.

Applications

MP3 Players, Pagers, and CD Players

PDAs and Organizers

Digital Still Cameras

Cordless Phones

Wireless Mice/Keyboards

Portable Medical Equipment

Other Battery-Powered Systems

Features

♦ Low Input (0.7V) and Output (1.8V) Voltage

Capability

♦ Internal Synchronous Rectifier

♦ High 94% Efficiency

♦ Fixed Output Voltages: 1.8V, 2.5V, 3V, and 3.3V

♦ Up to 2MHz Switching Allows Small External

Components and Low Output Ripple

♦ Automatic Pulse Skipping at Light Loads for

Extended Battery Life

♦ Low 70µA (typ) Operating Supply Current

(Measured at OUT)

♦ Low 2µA Logic-Controlled Shutdown

♦ True Shutdown Fully Discharges Output to

Ground

♦ Uses Only Small Ceramic Capacitors

♦ 75ms RESET Output Flag

Low Input/Output Voltage

________________________________________________________________ Maxim Integrated Products

1

LX

PGND

SHDN

8

7

BATT

OUT

GND

GND

RESET

TDFN

3mm x 3mm

TOP VIEW

1

2

3

4

6

5

MAX1947

Pin Configuration

Ordering Information

MAX1947

LX

GND

BATT

OUT

PGND

10µF

2.2µF

4.7µH

+1.8V, +2.5V,

+3.0V, +3.3V

RESET

SHDN

Typical Application Circuit

19-3086; Rev 0; 5/04

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.

*xy represents the output voltage code (e.g., 18 =1.8V).

Standard output voltages include 3.3V (33), 3.0V (30), 2.5V

(25), and 1.8V (18). Contact the factory for other output voltages

in 100mV increments between 1.8V and 3.3V; the minimum

order quantity is 25,000 units.

EVALUATION

KIT

AVAILABLE

PART

TEMP RANGE

PIN-PACKAGE

MAX1947ETAxy*

-40

°C to +85°C8 TDFN 3mm x 3mm

True Shutdown is a trademark of Maxim Integrated Products, Inc.