Detailed Description

MAX7319–MAX7329 Family Comparison

The MAX7319–MAX7323 family consists of five pin-

compatible, eight-port expanders. Each version is opti-

mized for different applications. The MAX7328 and

MAX7329 are second sources to the PCF8574 and

PCF8574A.

The MAX7324–MAX7327 family consists of four pin-

compatible, 16-port expanders that integrate the func-

tions of the MAX7320 and one of either the MAX7319,

MAX7321, MAX7322, or MAX7323.

Functional Overview

The MAX7321 is a general-purpose port expander

operating from a +1.71V to +5.5V supply that provides

eight open-drain I/O ports. Each open-drain output is

rated to sink 20mA, and the entire device is rated to

sink 100mA into all ports combined. The outputs drive

loads connected to supplies up to +6V, independent of

the MAX7321’s supply voltage.

(0x60 to 0x6F) using the address select inputs AD0 and

400kHz. The RST input clears the serial interface in

_______________________________________________________________________________________

5

PART

SLAVE

ADDRESS

INPUTS

INPUT

INTERRUPT

MASK

OPEN-

DRAIN

OUTPUTS

PUSH-

PULL

OUTPUTS

APPLICATION

8-PORT EXPANDERS

MAX7319

110xxxx

8

Yes

—

—

Input-only versions:

8 input ports with programmable latching transition

detection interrupt and selectable pullups.

Offers maximum versatility for automatic input

monitoring. An interrupt mask selects which inputs

cause an interrupt on transitions, and transition flags

identify which inputs have changed (even

momentarily) since the ports were last read.

MAX7320

101xxxx

——

—

8

Output-only versions:

8 push-pull outputs with selectable power-up default

levels.

Push-pull outputs offer faster rise time than open-

drain outputs, and require no pullup resistors.

MAX7321

110xxxx

Up to 8

—

Up to 8

—

I/O versions:

8 open-drain I/O ports with latching transition

detection interrupt and selectable pullups.

Open-drain outputs can level shift the logic-high

state to a higher or lower voltage than V+ using

external pullup resistors. Any port can be used as an

input by setting the open-drain output to logic high.

Transition flags identify which inputs have changed

(even momentarily) since the ports were last read.

MAX7322

110xxxx

4

Yes

—

4

4 input-only, 4 output-only versions:

4 input ports with programmable latching transition

detection interrupt and selectable pullups;

4 push-pull outputs with selectable power-up default

levels.

Table 1. MAX7321–MAX7329 Family Comparison