General Description

The MAX7321 2-wire serial-interfaced peripheral features

eight open-drain I/O ports with selectable internal pullups

and transition detection. Any port may be used as a logic

input or an open-drain output. Ports are overvoltage pro-

tected to +6V independent of supply voltage.

All I/O ports configured as inputs are continuously mon-

itored for state changes (transition detection). State

changes are indicated by the open-drain, +6V tolerant

INT output. The interrupt is latched, allowing detection

of transient changes. When the MAX7321 is subse-

quently accessed through the serial interface, any

pending interrupt is cleared.

The open-drain outputs are rated to sink 20mA and are

capable of driving LEDs.

The +6V tolerant RST input clears the serial interface,

MAX7321.

The MAX7321 uses two address inputs with four-level

address also determines the power-up logic level for

the I/O ports, and enables or disables internal 40k

Ω

pullups in groups of four ports.

The MAX7321 supports hot insertion. All eight I/O ports,

the serial interface SDA, SCL, AD0, AD2, INT, and RST

remain high impedance in power-down (V+ = 0) with

up to +6V asserted on them.

The MAX7321 is one device in a family of pin-compatible

port expanders with a choice of input ports, open-drain

I/O ports, and push-pull output ports (see Table 1).

The MAX7321 is available in 16-pin QSOP and 16-pin

TQFN packages, and is specified over the automotive

temperature range (-40°C to +125°C).

Features

♦ +1.71V to +5.5V Operating Voltage

♦ 8 Open-Drain I/O Ports Rated to 20mA Sink Current

♦ I/O Ports Are Overvoltage Protected to +6V

♦ Any Port Can Be a Logic Input or an Open-Drain

Output

♦ Selectable I/O Port Power-Up Default Logic Levels

♦ Transient Changes Are Latched, Allowing Detection

Between Read Operations

♦ INT Output Alerts Change on Inputs

♦ AD0 and AD2 Inputs Select from 16 Slave

Addresses

♦ Low 0.6µA (typ), 1.5µA (max) Standby Current

♦ -40°C to +125°C Operating Temperature

________________________________________________________________ Maxim Integrated Products

1

19-3738; Rev 0; 7/05

For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at

1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.

Ordering Information

PART

TEMP

RANGE

PIN-

PACKAGE

TOP

MARK

PKG

CODE

MAX7321AEE

-40°C to

+125°C

16 QSOP

—

E16-4

MAX7321ATE

-40°C to

+125°C

16 TQFN

3mm x 3mm

x 0.8mm

ADC

T1633-4

MAX7321ASE*

-40°C to

+125°C

16 SO

—

—

MAX7321AUP*

-40°C to

+125°C

20 TSSOP

—

—

MAX7321AAP*

-40°C to

+125°C

20 SSOP

—

—

Inc., or one of its sublicensed Associated Companies, conveys

Pin Configurations, Typical Application Circuit, and

Functional Diagram appear at end of data sheet.

Selector Guide

PART

INPUTS

INTERRUPT

MASK

OPEN-

DRAIN

OUTPUTS

PUSH-PULL

OUTPUTS

MAX7319

8

Yes

—

—

MAX7320

——

—

8

MAX7321

Up to 8

—

Up to 8

—

MAX7322

4

Yes

—

4

MAX7323

Up to 4

—

Up to 4

4

MAX7328

Up to 8

—

Up to 8

—

MAX7329

Up to 8

—

Up to 8

—

*Future product—contact factory for availability.

Cell Phones

SAN/NAS

Servers

Notebooks

Satellite Radio

Automotive

Applications