19-3738; Rev 0; 7/05
2
I C Port Expander with 8 Open-Drain I/Os
General Description
Features
♦ 400kHz, +6V Tolerant I2C Serial Interface
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.
♦ +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
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.
♦ 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
The open-drain outputs are rated to sink 20mA and are
capable of driving LEDs.
♦ AD0 and AD2 Inputs Select from 16 Slave
The +6V tolerant RST input clears the serial interface,
terminating any I2C* communication to or from the
MAX7321.
The MAX7321 uses two address inputs with four-level
logic to allow 16 I2C slave addresses. The slave
address also determines the power-up logic level for
the I/O ports, and enables or disables internal 40kΩ
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).
Addresses
♦ Low 0.6µA (typ), 1.5µA (max) Standby Current
♦ -40°C to +125°C Operating Temperature
Ordering Information
TEMP
PIN-
TOP
PKG
PART
RANGE PACKAGE
MARK CODE
-40°C to
16 QSOP
+125°C
MAX7321AEE
—
E16-4
16 TQFN
-40°C to
3mm x 3mm
+125°C
MAX7321ATE
ADC T1633-4
x 0.8mm
-40°C to
16 SO
—
—
—
MAX7321ASE*
MAX7321AUP*
MAX7321AAP*
—
—
—
+125°C
-40°C to
20 TSSOP
+125°C
-40°C to
20 SSOP
+125°C
Applications
Cell Phones
SAN/NAS
Servers
Notebooks
*Future product—contact factory for availability.
Satellite Radio
Automotive
Selector Guide
OPEN-
INTERRUPT
MASK
PUSH-PULL
DRAIN
PART
INPUTS
OUTPUTS
OUTPUTS
MAX7319
MAX7320
8
Yes
—
—
—
8
Pin Configurations, Typical Application Circuit, and
Functional Diagram appear at end of data sheet.
—
—
MAX7321 Up to 8
MAX7322
—
Up to 8
—
—
4
*Purchase of I2C components from Maxim Integrated Products,
Inc., or one of its sublicensed Associated Companies, conveys
a license under the Philips I2C Patent Rights to use these com-
ponents in an I2C system, provided that the system conforms
to the I2C Standard Specification as defined by Philips.
4
Yes
—
MAX7323 Up to 4
MAX7328 Up to 8
MAX7329 Up to 8
Up to 4
Up to 8
Up to 8
4
—
—
—
—
________________________________________________________________ Maxim Integrated Products
1
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.