Rainbow-electronics MAX1947 User Manual download pdf

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

MAX1947

Low Input/Output Voltage

Step-Up DC-DC Converter with

RESET

________________________________________________________________ Maxim Integrated Products 1

PGNDSHDN

BATT

OUTGND

GND

RESET

TDFN

3mm x 3mm

TOP VIEW

MAX1947

Pin Configuration

Ordering Information

MAX1947

GND

BATT

OUT

PGND

10µF

2.2µF

4.7µH

OUT

+1.8V, +2.5V,

+3.0V, +3.3V

+0.7V TO +V

OUT

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.

1 2 3 4 5 6 7 8 9 10

Summary of Contents

Page 1 - Step-Up DC-DC Converter with

General DescriptionThe MAX1947 is a compact, high-efficiency, step-up DC-DC converter that regulates output voltages from 1.8V to3.3V to power µP/DSP

Page 2

MAX1947Low Input/Output Voltage Step-Up DC-DC Converter with RESETMaxim cannot assume responsibility for use of any circuitry other than circuitry ent

Page 3

MAX1947Low Input/Output Voltage Step-Up DC-DC Converter with RESET2 __________________________________________________________________________________

Page 4

MAX1947Low Input/Output Voltage Step-Up DC-DC Converter with RESET____________________________________________________________________________________

Page 5

MAX1947Low Input/Output Voltage Step-Up DC-DC Converter with RESET4 __________________________________________________________________________________

Page 6

MAX1947Low Input/Output Voltage Step-Up DC-DC Converter with RESET____________________________________________________________________________________

Page 7

MAX1947Detailed DescriptionThe MAX1947 compact step-up DC-DC converter startsup with voltages as low as 0.8V and operates with inputvoltages down to 0

Page 8

Control SchemeThe MAX1947 is a bootstrapped design. Upon turn-on,a startup oscillator brings the output voltage highenough to allow the main DC-DC cir

Page 9

MAX1947ShutdownThe MAX1947 enters shutdown mode when SHDN is driven low. During shutdown, the synchronous rectifierdisconnects the output from the inp

Page 10

Calculate the maximum output current (IOUTMAX) usinginductor ripple current (IRIPPLE) and duty cycle (D) asfollows:Here, ILIMis the NFET current limit

Comments to this Manuals

No comments

Rainbow-electronics MAX1947 User Manual

Browse online or download User Manual for Sensors Rainbow-electronics MAX1947. Rainbow Electronics MAX1947 User Manual [en]

Summary of Contents

Comments to this Manuals

Related products and manuals for Sensors Rainbow-electronics MAX1947