Rainbow-electronics MAX763A Manual de usuario descargar pdf

__________________General Description

The MAX748A/MAX763A are 3.3V-output CMOS, step-

down switching regulators. The MAX748A accepts

inputs from 3.3V to 16V and delivers up to 500mA. The

MAX763A accepts inputs between 3.3V and 11V and

delivers up to 500mA. Typical efficiencies are 85% to

90%. Quiescent supply current is 1.4mA (MAX763A),

and only 0.2µA in shutdown.

Pulse-width-modulation (PWM) current-mode control pro-

vides precise output regulation and excellent transient

responses. Output voltage accuracy is guaranteed to be

±5% over line, load, and temperature variations.

Fixed-frequency switching allows easy filtering of output

ripple and noise, as well as the use of small external

components. A 22µH inductor works in most applica-

tions, so no magnetics design is necessary.

The MAX748A/MAX763A also feature cycle-by-cycle cur-

rent limiting, overcurrent limiting, undervoltage lockout,

and programmable soft-start protection. The MAX748A

is available in 8-pin DIP and 16-pin wide SO packages;

the MAX763A comes in 8-pin DIP and SO packages.

___________________________Applications

5V-to-3.3V Converters

Cellular Phones

Portable Instruments

Hand-Held Computers

Computer Peripherals

________________________________Features

♦ Up to 500mA Load Currents

♦ Guaranteed 159kHz to 219.5kHz Current-Mode

PWM

♦ 85% to 90% Efficiencies

♦ 1.7mA Quiescent Current (MAX748A)

1.4mA Quiescent Current (MAX763A)

♦ 0.2µA Shutdown Supply Current

♦ 22µH Preselected Inductor Value;

No Component Design Required

♦ Overcurrent, Soft-Start, and Undervoltage

Lockout Protection

♦ Cycle-by-Cycle Current Limiting

♦ 8-Pin DIP/SO Packages (MAX763A)

_________________Ordering Information

PART TEMP. RANGE PIN-PACKAGE

MAX748ACPA 0°C to +70°C 8 Plastic DIP

MAX748ACWE 0°C to +70°C 16 Wide SO

MAX748AC/D 0°C to +70°C Dice*

MAX748AEPA -40°C to +85°C 8 Plastic DIP

MAX748AEWE -40°C to +85°C 16 Wide SO

MAX748AMJA -55°C to +125°C 8 CERDIP

MAX748A/MAX763A

3.3V, Step-Down,

Current-Mode PWM DC-DC Converters

_______________________________________________________________________

Maxim Integrated Products

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

19-0190; Rev 0; 9/93

Ordering Information continued on last page.

* Contact factory for dice specifications.

____________________Pin Configurations

MAX748A



INPUT

3.3V TO 16V

V+

OUT

GNDSS

REF

SHDNON/OFF

22µH

OUTPUT

3.3V

100µF

____________Typical Operating Circuit

TOP VIEW

V+

GND

OUT

REF

MAX748A

MAX763A



DIP

SHDN

Pin Configurations continued on last page.

1 2 3 4 5 6 ... 11 12

MAX748A/MAX763A 1
3.3V, Step-Down 1

Indice de contenidos

Pagina 1 - 3.3V, Step-Down

__________________General DescriptionThe MAX748A/MAX763A are 3.3V-output CMOS, step-down switching regulators. The MAX748A acceptsinputs from 3.3V to

Pagina 2

MAX748A/MAX763A3.3V, Step-Down,Current-Mode PWM DC-DC Converters10 ___________________________________________________________________________________

Pagina 3