Rainbow-electronics MAX747 Manual de usuario descargar pdf

_______________General Description

The MAX747 high-efficiency, high-current, step-down

controller drives external P-channel FETs. It provides

90% to 95% efficiency from a 6V supply with load

currents ranging from 50mA up to 2.5A. It uses a

pulse-width-modulating (PWM) current-mode control

scheme to provide precise output regulation and low

output noise. The MAX747’s 4V to 15V input voltage

range, a fixed 5V/adjustable (Dual-Mode™) output, and

a current limit set with an external resistor make this

device ideal for a wide range of applications.

High efficiency is maintained with light loads due to a

proprietary dual-control (Idle-Mode™) scheme that

minimizes switching losses by reducing the switching

frequency at light loads. The low 800µA quiescent

current and ultra-low 0.6µA shutdown current further

extend battery life.

External components are protected by the MAX747’s

cycle-by-cycle current limit. The MAX747 also features a

2V ±1.5% reference, a comparator for low-battery

detection or level translating, as well as soft-start and

shutdown capability.

The MAX746, discussed in a separate data sheet,

functions similarly to the MAX747, but it drives N-channel

logic level FETs on the high side.

________________________Applications

Notebook Power Supplies

Personal Digital Assistants

Battery-Operated Equipment

Cellular Phones

5V to 3.3V Green PC Applications

____________________________Features

♦ 90% to 95% Efficiency for 50mA to 2.5A

Output Currents

♦ 4V to 15V Input Voltage Range

♦ Low 800µA Supply Current

♦ 0.6µA Shutdown Current

♦ Drives External P-Channel FETs

♦ Cycle-by-Cycle Current Limiting

♦ 2V ±1.5% Accurate Reference Output

♦ Adjustable Soft-Start

♦ Precision Comparator for Power-Fail or

Low-Battery Warning

______________Ordering Information

* Contact factory for dice specifications.

MAX747

High-Efficiency PWM, Step-Down

P-Channel DC-DC Controller

________________________________________________________________

Maxim Integrated Products

OUTPUT

5V

2.3A

INPUT

6V TO 15V

AV+

EXT

OUT

GND

430µF

REF

MAX747

SHDN

ON/OFF

LBI

LOW-BATTERY

DETECTOR

INPUT

V+

LOW-BATTERY

DETECTOR

OUTPUT

AGNDFBCCSS

LBO

5OmΩ

5OµH

0.1µF

100µF

__________________Pin Configuration

GND

AV+

LBI

DIP/SO

TOP VIEW

MAX747

OUT

AGND

REF

SHDN

LBO

V+

EXT

__________Typical Operating Circuit

Call toll free 1-800-998-8800 for free samples or literature.

19-0171; Rev 1; 9/93

PART TEMP. RANGE PIN-PACKAGE

MAX747CPD 0°C to +70°C 14 Plastic DIP

MAX747CSD 0°C to +70°C 14 Narrow SO

MAX747C/D 0°C to +70°C Dice*

MAX747EPD -40°C to +85°C 14 Plastic DIP

MAX747ESD -40°C to +85°C 14 Narrow SO

MAX747MJD -55°C to +125°C 14 CERIDIP

™ Dual-Mode and Idle-Mode are trademarks of Maxim Integrated Products.

1 2 3 4 5 6 ... 11 12

P-Channel DC-DC Controller 1

Indice de contenidos

Pagina 1 - P-Channel DC-DC Controller

_______________General DescriptionThe MAX747 high-efficiency, high-current, step-downcontroller drives external P-channel FETs. It provides90% to 95%

Pagina 2

gate capacitance, because that energy is dissipatedby the gate-drive circuitry, not the P-FET.The Standard Application Circuit(Figure 1a, 1b) usesan 8

Pagina 3

MAX747High-Efficiency PWM, Step-Down P-Channel DC-DC Controller______________________________________________________________________________________

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Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses arei

Pagina 5

MAX747High-Efficiency PWM, Step-Down P-Channel DC-DC Controller2 _____________________________________________________________________________________

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MAX747High-Efficiency PWM, Step-Down P-Channel DC-DC Controller_______________________________________________________________________________________

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MAX747High-Efficiency PWM, Step-Down P-Channel DC-DC Controller4 _____________________________________________________________________________________

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MAX747High-Efficiency PWM, Step-Down P-Channel DC-DC Controller_______________________________________________________________________________________

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MAX747High-Efficiency PWM, Step-Down P-Channel DC-DC Controller6 _____________________________________________________________________________________

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MAX747High-Efficiency PWM, Step-Down P-Channel DC-DC Controller_______________________________________________________________________________________

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With decreasing loads, as the inductor current becomesdiscontinuous, traditional PWM converters continue toswitch at a fixed frequency, decreasing lig

Pagina 12

MAX747High-Efficiency PWM, Step-Down P-Channel DC-DC Controller_______________________________________________________________________________________

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Rainbow-electronics MAX747 Manual de usuario

Busca en linea o descarga Manual de usuario para Sensores Rainbow-electronics MAX747. Rainbow Electronics MAX747 User Manual [en] Manual de usuario

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