Rainbow Electronics MAX763A - Manual

__________________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
MAX748A CPA 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 1
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+
LX
OUT
CC
GND SS
REF
SHDN ON/OFF
22 µ H
OUTPUT
3.3V
100 µ F
____________Typical Operating Circuit
TOP VIEW
1
2
3
4
8
7
6
5
V+
LX
GND
OUT CC
SS
REF
MAX748A
MAX763A
DIP
SHDN
Pin Configurations continued on last page.