_______________General Description

The MAX770–MAX773 step-up switching controllers pro-

vide 90% efficiency over a 10mA to 1A load. A

unique current-limited pulse-frequency-modulation (PFM)

control scheme gives these devices the benefits of

pulse-width-modulation (PWM) converters (high efficiency

at heavy loads), while using less than 110µA of supply

current (vs. 2mA to 10mA for PWM converters).

These ICs use tiny external components. Their high

switching frequencies (up to 300kHz) allow surface-

mount magnetics of 5mm height and 9mm diameter.

The MAX770/MAX771/MAX772 accept input voltages

from 2V to 16.5V. Output voltages are preset at 5V,

(MAX770), 12V (MAX771), and 15V (MAX772); they can

also be adjusted using two resistors.

The MAX773 accepts inputs from 3V to 16.5V. For a wider

input range, it features an internal shunt regulator that

allows unlimited higher input voltages. The MAX773’s out-

put can be set to 5V, 12V, or 15V, or it can be adjusted

with two resistors.

The MAX770–MAX773 drive external N-channel MOSFET

switches, allowing them to power loads up to 15W. If less

power is required, use the MAX756/MAX757 or

MAX761/MAX762 step-up switching regulators with on-

board MOSFETs.

________________________Applications

Palmtops/Handy-Terminals

High-Efficiency DC-DC Converters

Battery-Powered Applications

Positive LCD-Bias Generators

Portable Communicators

Flash Memory Programmers

____________________________Features

o 90% Efficiency for 10mA to 1A Load Currents

o Up to 15W Output Power

o 110µA Max Supply Current

o 5µA Max Shutdown Current

o 2V to 16.5V Input Range

(MAX770/MAX771/MAX772)

o Internal Shunt Regulator for High Input Voltages

(MAX773)

o Preset or Adjustable Output Voltages

MAX770: 5V or Adjustable

MAX771: 12V or Adjustable

MAX772: 15V or Adjustable

MAX773: 5V, 12V, 15V, or Adjustable

o Current-Limited PFM Control Scheme

o 300kHz Switching Frequency

______________Ordering Information

Ordering Information continued at end of data sheet.

*Contact factory for dice specifications.

**Contact factory for availability and processing to MIL-STD-883B.

5V/12V/15V or Adjustable, High-Efficiency,

________________________________________________________________

Maxim Integrated Products

1

1

2

3

4

8

7

6

5

CS

GND

AGND

REF

SHDN

FB

V+

EXT

MAX770

MAX771

MAX772

DIP/SO

_________________Pin Configurations

FB AGND GND

V+

CS

EXT

N

REF

SHDN

ON/OFF

OUTPUT

12V

INPUT

2V TO VOUT

MAX771

__________Typical Operating Circuit

PART

TEMP. RANGE

PIN-PACKAGE

MAX770CPA

0°C to +70°C

Plastic DIP

MAX770CSA

0°C to +70°C

8 SO

MAX770C/D

0°C to +70°C

Dice*

MAX770EPA

-40°C to +85°C

8 Plastic DIP

MAX770ESA

-40°C to +85°C

8 SO

MAX770MJA

-55°C to +125°C

8 CERDIP**

TOP VIEW

Pin Configurations continued at end of data sheet.

19-0202; Rev 2; 11/96

EVALUATION

KIT MANUAL

FOLLOWS

DATA

SHEET

For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800.

For small orders, phone 408-737-7600 ext. 3468.