Rainbow-electronics MAX1557 Manual do Utilizador descarregar pdf

General Description

The MAX1556/MAX1557 are low-operating-current

(16µA), fixed-frequency step-down regulators. High effi-

ciency, low-quiescent operating current, low dropout,

and minimal (27µA) quiescent current in dropout make

these converters ideal for powering portable devices

from 1-cell Li-ion or 3-cell alkaline/NiMH batteries. The

MAX1556 delivers up to 1.2A; has pin-selectable 1.8V,

2.5V, and 3.3V outputs; and is also adjustable. The

MAX1557 delivers up to 600mA; has pin-selectable 1V,

1.3V, and 1.5V outputs; and is also adjustable.

The MAX1556/MAX1557 contain a low-on-resistance

internal MOSFET switch and synchronous rectifier to

maximize efficiency and dropout performance while

minimizing external component count. A proprietary

topology offers the benefits of a high fixed-frequency

operation while still providing excellent efficiency at

both light and full loads. A 1MHz PWM switching fre-

quency keeps components small. Both devices also

feature an adjustable soft-start to minimize battery tran-

sient loading.

The MAX1556/MAX1557 are available in a tiny 10-pin

TDFN (3mm x 3mm) package.

Applications

PDAs and Palmtop Computers

Cell Phones and Smart Phones

Digital Cameras and Camcorders

Portable MP3 and DVD Players

Hand-Held Instruments

Features

♦ Up to 97% Efficiency

♦ 95% Efficiency at 1mA Load Current

♦ Low 16µA Quiescent Current

♦ 1MHz PWM Switching

♦ Tiny 3.3µH Inductor

♦ Selectable 3.3V, 2.5V, 1.8V, 1.5V, 1.3V, 1.0V, and

Adjustable Output

♦ 1.2A Guaranteed Output Current (MAX1556)

♦ Voltage Positioning Optimizes Load-Transient

Response

♦ Low 27µA Quiescent Current in Dropout

♦ Low 0.1µA Shutdown Current

♦ No External Schottky Diode Required

♦ Analog Soft-Start with Zero Overshoot Current

♦ Small, 10-Pin, 3mm x 3mm TDFN Package

MAX1556/MAX1557

16µA I

, 1.2A PWM

Step-Down DC-DC Converters

________________________________________________________________ Maxim Integrated Products 1

TOP VIEW

OUT

SHDN

INP

GND

PGND

TDFN

MAX1556/

MAX1557

Pin Configuration

Ordering Information

OFF

SHDN

GND

INPUT

2.6V TO 5.5V

VOLTAGE

SELECT

OUTPUT

0.75V TO V

PGND

OUT

INP

MAX1556/

MAX1557

Typical Operating Circuit

19-3336; Rev 0; 7/04

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.

EVALUATION KIT

AVAILABLE

PART

TEMP RANGE

PIN-PACKAGE

TOP

MARK

MAX1556ETB

-40°C to +85°C

10 TDFN-EP*

(T1033-1)

ACQ

MAX1557ETB

-40°C to +85°C

10 TDFN-EP*

(T1033-1)

ACR

*EP = Exposed paddle.

1 2 3 4 5 6 ... 11 12

Resumo do Conteúdo

Página 1 - Step-Down DC-DC Converters

General DescriptionThe MAX1556/MAX1557 are low-operating-current(16µA), fixed-frequency step-down regulators. High effi-ciency, low-quiescent operatin

Página 2

MAX1556/MAX1557Inductor SelectionA 4.7µH inductor with a saturation current of at least800mA is recommended for the MAX1557 full-load(600mA) applicati

Página 3

MAX1556/MAX155716µA IQ, 1.2A PWM DC-DC Step-Down Converters______________________________________________________________________________________ 11Pa

Página 4

MAX1556/MAX155716µA IQ, 1.2A PWM DC-DC Step-Down ConvertersMaxim cannot assume responsibility for use of any circuitry other than circuitry entirely e

Página 5

MAX1556/MAX155716µA IQ, 1.2A PWM DC-DC Step-Down Converters2 _______________________________________________________________________________________AB

Página 6

MAX1556/MAX155716µA IQ, 1.2A PWM DC-DC Step-Down Converters_______________________________________________________________________________________ 3No

Página 7

MAX1556/MAX155716µA IQ, 1.2A PWM DC-DC Step-Down Converters4 _______________________________________________________________________________________Ty

Página 8

MAX1556/MAX155716µA IQ, 1.2A PWM DC-DC Step-Down Converters_______________________________________________________________________________________ 5LI

Página 9

MAX1556/MAX155716µA IQ, 1.2A PWM DC-DC Step-Down Converters6 _______________________________________________________________________________________De

Página 10 - Step-Down Converters

MAX1556/MAX155716µA IQ, 1.2A PWM DC-DC Step-Down Converters_______________________________________________________________________________________ 7LX

Página 11

As the load current decreases, the converters enter apulse-skip mode in which the PWM comparator is dis-abled. At light loads, efficency is enhanced b

Página 12

MAX1556/MAX155716µA IQ, 1.2A PWM DC-DC Step-Down Converters_______________________________________________________________________________________ 9(R

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Rainbow-electronics MAX1557 Manual do Utilizador

Consulte online ou descarregue Manual do Utilizador para Sensores Rainbow-electronics MAX1557. Rainbow Electronics MAX1557 User Manual Manual do Utilizador

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