General Description

The MAX1802 provides a complete power-supply solu-

tion for digital still cameras and video cameras by inte-

grating two high-efficiency step-down DC-DC converters

and three auxiliary step-up controllers. This complete

solution is targeted for applications that use either three

to four alkaline cells or two lithium-ion (Li+) cells.

The main step-down DC-DC controller accepts inputs

from 2.5V to 11V and regulates a resistor-adjustable out-

put from 2.7V to 5.5V. It uses a synchronous rectifier to

regulate the output with up to 94% efficiency. An

adjustable operating frequency (up to 1MHz) facilitates

designs for optimum size, cost, and efficiency.

The core step-down DC-DC converter accepts inputs

from 2.7V to 5.5V and regulates a resistor-adjustable

output from 1.25V to 5.5V. It delivers 500mA with up to

94% efficiency.

The three auxiliary step-up controllers can be used to

power the digital camera’s CCD, LCD, and backlight.

The MAX1802 also features expandability by supplying

power, an oscillator signal, and a reference to the

MAX1801, a low-cost slave DC-DC controller that sup-

ports step-up, single-ended primary inductance con-

verter (SEPIC), and fly-back configurations.

The MAX1802 is available in a space-saving 32-pin

TQFP package (5mm x 5mm body), and the MAX1801

is available in an 8-pin SOT-23 package. An evaluation

kit (MAX1802EVKIT) featuring both devices is available

to expedite designs.

________________________Applications

Digital Still Cameras

Digital Video Cameras

Hand-Held Devices

Internet Access Tablets

PDAs

DVD Players

Features

o 2.5V to 11V Input Voltage Range

o Main DC-DC Controller

94% Efficiency

+2.7V to +5.5V Adjustable Output Voltage

Up to 100% Duty Cycle

Independent Shutdown

o Core DC-DC Converter

94% Efficiency

Up to 500mA Load Efficiency

Output Voltage Adjustable Down to 1.25V

Independent Shutdown

o Three Auxiliary DC-DC Controllers

Adjustable Maximum Duty Cycle

Independent Shutdown

o Power, Oscillator, and Reference Outputs to Drive

External Slave Controllers (MAX1801)

o Up to 1MHz Switching Frequency

o 3µA Supply Current in Shutdown Mode

o Internal Soft-Start

o Overload Protection for All DC-DC Converters

o Compact 32-Pin TQFP Package

Digital Camera Step-Down

Power Supply

________________________________________________________________ Maxim Integrated Products

1

Typical Operating Circuit

19-1850; Rev 0; 10/00

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.

Ordering Information

Note: Refer to the separate data sheet for MAX1801EKA in an 8-

pin SOT.

Pin Configuration appears at end of data sheet.

32 TQFP

PIN-PACKAGE

TEMP. RANGE

-40°C to +85°C

MAX1802EHJ

PART

MAX1802

MASTER

MAX1801

SLAVE

INPUT

2.5V TO 11V

OSC

POWER

REF

MOTOR

CORE

MAIN

CCD

CCFL

TFT