General Description

The MAX1522/MAX1523/MAX1524 are simple, compact

boost controllers designed for a wide range of DC-DC

conversion topologies, including step-up, SEPIC, and

flyback applications. They are for applications where

extremely low cost and small size are top priorities.

These devices are designed specifically to provide a

simple application circuit and minimize the size and

number of external components, making them ideal for

PDAs, digital cameras, and other low-cost consumer

electronics applications.

These devices use a unique fixed on-time, minimum off-

time architecture, which provides excellent efficiency

over a wide-range of input/output voltage combinations

and load currents. The fixed on-time is pin selectable to

either 0.5µs (50% max duty cycle) or 3µs (85% max

duty cycle), permitting optimization of external compo-

nent size and ease of design for a wide range of output

voltages.

The MAX1522/MAX1523 operate from a +2.5V to +5.5V

input voltage range and are capable of generating a

wide range of outputs. The MAX1524 is intended for

bootstrapped operation, permitting startup with lower

input voltage. All devices have internal soft-start and

short-circuit protection to prevent excessive switching

current during startup and under output fault condi-

tions. The MAX1522/MAX1524 have a latched fault

mode, which shuts down the controller when a short-

circuit event occurs, whereas the MAX1523 reenters

soft-start mode during output fault conditions. The

MAX1522/MAX1523/MAX1524 are available in a space-

saving 6-pin SOT23 package.

________________________Applications

____________________________Features

o Simple, Flexible Application Circuit

o 2-Cell NiMH or Alkaline Operation (MAX1524)

o Low Quiescent Current (25µA typ)

o Output Fault Protection and Soft-Start

o Pin-Selectable Maximum Duty Factor

o Micropower Shutdown Mode

o Small 6-Pin SOT23 Package

o No Current-Sense Resistor

Simple SOT23 Boost Controllers

________________________________________________________________ Maxim Integrated Products

1

__________Typical Operating Circuit

19-1926; Rev 0; 2/01

For price, delivery, and to place orders, please contact Maxim Distribution 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

MAX1522EUT-T

-40

°C to +85°C

6 SOT23-6

AAOX

MAX1523EUT-T

-40

°C to +85°C

6 SOT23-6

AAOY

MAX1524EUT-T

-40

°C to +85°C

6 SOT23-6

AAOZ

Ordering Information

Pin Configurations

FB

SHDN

SET

16

5

EXT

GND

MAX1522

MAX1523

MAX1524

SOT23-6

TOP VIEW

2

34

MAX1522

MAX1523

MAX1524

INPUT

OFF ON

6

3

4

5

2

1

EXT

SET

FB

SHDN

GND

OUTPUT

50% 85%

N

Low-Cost, High-Current,

or High-Voltage Boost

Conversion

LCD Bias Supplies

Industrial +24V and +28V

Power Supplies

Low-Cost, Multi-Output

Flyback Converters

SEPIC Converters

Low-Cost Battery-

Powered Applications