Datasheet MAX7322 Datasheet (MAXIM)

General Description

The MAX7322 2-wire serial-interfaced peripheral features
four push-pull outputs and four input ports with selectable
internal pullups. Input ports are overvoltage protected to
+6V and feature transition detection with interrupt output.

The four input ports are continuously monitored for state
changes (transition detection). The interrupt is latched,
allowing detection of transient changes. Any combination
of inputs can be selected using the interrupt mask to
assert the open-drain INT output. When the MAX7322 is
subsequently accessed through the serial interface, any
pending interrupt is cleared.

The four push-pull outputs are rated to sink 20mA, and
are capable of driving LEDs.

The RST input clears the serial interface, terminating any
I

2

C communication to or from the MAX7322.

The MAX7322 uses two address inputs with four-level
logic to allow 16 I

2

C slave addresses. The slave address
also sets the power-up default logic state for the four out­put ports, and enables or disables internal 40kΩ pullups
for the input ports.

The MAX7322 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 MAX7322 is available in 16-pin QSOP and TQFN
packages, and is specified over the -40°C to +125°C
automotive temperature range.

Applications

Features

♦ 400kHz I2C Serial Interface
♦ +1.71V to +5.5V Operation Voltage
♦ 4 Push-Pull Output Ports Rated at 20mA Sink

Current

♦ 4 Input Ports with Maskable, Latching Transition

Detection

♦ Input Ports are Overvoltage Protected to +6V
♦ Transient Changes are Latched, Allowing

Detection Between Read Operations

♦ INT Output Alerts Change on Any Selection of

Inputs

♦ AD0 and AD2 Inputs Select from 16 Slave

Addresses

♦ Low 0.6µA (typ) Standby Current
♦ -40°C to +125°C Operating Temperature Range

MAX7322

I2C Port Expander with

4 Push-Pull Outputs and 4 Inputs

________________________________________________________________ Maxim Integrated Products 1

19-3787; Rev 1; 9/06

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.

EVALUATION KIT

AVAILABLE

Ordering Information

Typical Application Circuit and Functional Diagram appear
at end of data sheet.

Cell Phones
SAN/NAS
Servers

Notebooks
Satellite Radio
Automotive

Selector Guide

+Denotes lead-free package.

*EP = Exposed paddle.

Pin Configurations

Pin Configurations continued at end of data sheet.

TOP VIEW

SDA

AD0

RST

SCL

12 10 9

13

14

15

*EP

16

+

13V+4

AD2

(3mm x 3mm)

11

MAX7322

2

O0 INT

TQFN

O7

O6

I5

8

I4

7

GND

6

I3

5

I2

O1

PART

MAX7322AEE+

MAX7322ATE+

TEMP

RANGE

-40°C to
+125°C

-40°C to
+125°C

PIN­PACKAGE

16 QSOP — E16-4

16 TQFN-EP*
(3mm x 3mm)

TOP

MARK

ADD T1633-4

PKG

CODE

PART INPUTS

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 —

INTERRUPT

MASK

OPEN­DRAIN

OUTPUTS

PUSH-PULL

OUTPUTS

MAX7322

I2C Port Expander with
4 Push-Pull Outputs and 4 Inputs

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
absolute maximum rating conditions for extended periods may affect device reliability.

(All voltages referenced to GND.)

Supply Voltage V+....................................................-0.3V to +6V

SCL, SDA, AD0, AD2, RST, INT, I2–I5......................-0.3V to +6V

O0, O1, O6, O7 .................................................-0.3 to V+ + 0.3V

O0, O1, O6, O7 Output Current........................................±25mA

SDA Sink Current ............................................................... 10mA

INT Sink Current..................................................................10mA

Total V+ Current..................................................................50mA

Total GND Current ...........................................................100mA

Continuous Power Dissipation (T

A

= +70°C)

16-Pin QSOP (derate 8.3mW/°C above +70°C)...........667mW

16-Pin TQFN (derate 15.6mW/°C above +70°C) .......1250mW

Operating Temperature Range .........................-40°C to +125°C

Junction Temperature......................................................+150°C

Storage Temperature Range .............................-65°C to +150°C

Lead Temperature (soldering, 10s) .................................+300°C

DC ELECTRICAL CHARACTERISTICS

(V+ = +1.71V to +5.5V, TA= -40°C to +125°C, unless otherwise noted. Typical values are at V+ = +3.3V, TA= +25°C.) (Note 1)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Operating Supply Voltage V+ 1.71 5.50 V

Power-On Reset Voltage V

Standby Current
(Interface Idle)

Supply Current
(Interface Running)

Input High Voltage
SDA, SCL, AD0, AD2, RST, I2–I5

Input Low Voltage
SDA, SCL, AD0, AD2, RST, I2–I5

Input Leakage Current
SDA, SCL, AD0, AD2, RST, I2–I5

Input Capacitance
SDA, SCL, AD0, AD2, RST, I2–I5

Output Low Voltage
O0, O1, O6, O7

Output High Voltage
O0, O1, O6, O7

Output Low Voltage SDA V
Output Low Voltage INT V

Port Input Pullup Resistor R

I

POR

I

STB

I

V

V

IH

V

OL

V

OH

OLSDAISINK

OLINTISINK

PU

V+ falling 1.6 V

SCL and SDA and other digital inputs at
V+

f

+

IH

IL

, I

IL

= 400kHz; other digital inputs at V+ 23 55 µA

SCL

V+ < 1.8V 0.8 x V+

V+ ≥ 1.8V 0.7 x V+

V+ < 1.8V 0.2 x V+

V+ ≥ 1.8V 0.3 x V+
SDA, SCL, AD0, AD2, RST, at V+ or

GND, internal pullup disabled

V+ = +1.71V, I

V+ = +2.5V, I

V+ = +3.3V, I

V+ = +5V, I

V+ = +1.71V, I

V+ = +2.5V, I

V+ = +3.3V, I

V+ = +5V, I

= 6mA 250 mV

= 5mA 130 250 mV

= 5mA 90 180

SINK

= 10mA 110 210

SINK

= 15mA 130 230

SINK

= 20mA 140 250

SINK

= 2mA V+ - 250 V+ - 30

SOURCE

= 5mA V+ - 360 V+ - 70

SOURCE

= 5mA V+ - 260 V+ - 100

SOURCE

= 10mA V+ - 360 V+ - 120

SOURCE

0.6 1.5 µA

-0.2 +0.2 µA

10 pF

25 40 55 kΩ

V

V

mV

mV

MAX7322

I2C Port Expander with

4 Push-Pull Outputs and 4 Inputs

_______________________________________________________________________________________ 3

PORT AND INTERRUPT INT TIMING CHARACTERISTICS

(V+ = +1.71V to +5.5V, TA= -40°C to +125°C, unless otherwise noted. Typical values are at V+ = +3.3V, TA= +25°C.) (Note 1)

TIMING CHARACTERISTICS

(V+ = +1.71V to +5.5V, TA= -40°C to +125°C, unless otherwise noted. Typical values are at V+ = +3.3V, TA= +25°C.) (Note 1)

Note 1: All parameters are tested at TA= +25°C. Specifications over temperature are guaranteed by design.
Note 2: A master device must provide a hold time of at least 300ns for the SDA signal (referred to V

IL

of the SCL signal) in order to

bridge the undefined region of SCL’s falling edge.

Note 3: Guaranteed by design.
Note 4: C

b

= total capacitance of one bus line in pF. tRand tFmeasured between 0.3 x V+ and 0.7 x V+ with I

SINK

≤ 6mA.

Note 5: Input filters on the SDA and SCL inputs suppress noise spikes less than 50ns.

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Port Output Data Valid t

Port Input Setup Time t

Port Input Hold Time t

INT Input Data Valid Time t
INT Reset Delay Time from STOP t

INT Reset Delay Time from

Acknowledge

PPV

PSU

PH

t

CL ≤ 100pF 4 µs

CL ≤ 100pF 0 µs

CL ≤ 100pF 4 µs

CL ≤ 100pF 4 µs

IV

CL ≤ 100pF 4 µs

IP

CL ≤ 100pF 4 µs

IR

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Serial Clock Frequency f

Bus Free Time Between a STOP
and a START Condition

Hold Time (Repeated) START
Condition

Repeated START Condition
Setup Time

STOP Condition Setup Time t

Data Hold Time t

Data Setup Time t

SCL Clock Low Period t

SCL Clock High Period t

Rise Time of Both SDA and SCL
Signals, Receiving

Fall Time of Both SDA and SCL
Signals, Receiving

Fall Time of SDA, Transmitting t

Pulse Width of Spike Suppressed t

Capacitive Load for Each Bus
Line

RST Pulse Width t

RST Rising to START Condition

Setup Time

t

HD, STA

t

SU, STA

SU, STO

HD, DAT

SU, DAT

SCL

t

BUF

LOW

HIGH

t

R

t

F

F,TX

SP

C

b

W

t

RST

1.3 µs

0.6 µs

0.6 µs

0.6 µs

(Note 2) 0.9 µs

100 ns

1.3 µs

0.7 µs

(Notes 3, 4)

(Notes 3, 4)

(Notes 3, 4)

(Note 5) 50 ns

(Note 3) 400 pF

500 ns

20 +

0.1C

20 +

0.1C

20 +

0.1C

1µs

400 kHz

300 ns

b

300 ns

b

250 ns

b

MAX7322

I2C Port Expander with
4 Push-Pull Outputs and 4 Inputs

4 _______________________________________________________________________________________

Typical Operating Characteristics

(TA = +25°C, unless otherwise noted.)

0

0.4

0.2

1.0

0.8

0.6

1.2

1.4

1.8

1.6

2.0

-40 -10 5-25 203550658095110125

STANDBY CURRENT vs. TEMPERATURE

MAX7322 toc01

TEMPERATURE (°C)

STANDBY CURRENT (μA)

V+ = +3.3V

V+ = +2.5V

V+ = +5.0V

V+ = +1.71V

f

SCL

= 0kHz

0

20

10

40

30

50

60

-40 -10 5 20-25 3550658095110125

SUPPLY CURRENT vs. TEMPERATURE

MAX7322 toc02

TEMPERATURE (°C)

SUPPLY CURRENT (μA)

V+ = +3.3V

V+ = +5.0V

V+ = +1.71V

V+ = +2.5V

f

SCL

= 400kHz

OUTPUT VOLTAGE LOW

vs. TEMPERATURE

TEMPERATURE (°C)

OUTPUT VOLTAGE LOW (V)

MAX7322 toc03

-40 -25 -10 5 20 35 50 65 80 95 110 125

0

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

V+ = +3.3V
I

SINK

= 15mA

V+ = +5.0V
I

SINK

= 20mA

V+ = +2.5V
I

SINK

= 10mA

V+ = +1.71V
I

SINK

= 5mA

OUTPUT VOLTAGE HIGH

vs. TEMPERATURE

TEMPERATURE (°C)

OUTPUT VOLTAGE HIGH (V)

MAX7322 toc04

-40 -25 -10 5 20 35 50 65 80 95 110 125

0

1

2

3

4

5

6

V+ = +3.3V
I

SOURCE

= 5mA

V+ = +5.0V
I

SOURCE

= 10mA

V+ = +2.5V
I

SOURCE

= 5mA

V+ = +1.71V
I

SOURCE

= 2mA

Pin Description

PIN

QSOP TQFN

1, 3 15, 1 AD0, AD2

216 RST Reset Input. Active Low. Drive RST low to clear the 2-wire interface.

4, 5, 11, 12, 2, 3, 9, 10 O0, O1, O6, O7 Push-Pull Output Ports

6, 7, 9, 10 4, 5, 7, 8 I2–I5 Input Ports. I2 to I5 are CMOS-logic inputs protected to +6V.

8 6 GND Ground

13 11 INT Interrupt Output, Active Low. INT is an open-drain output.

14 12 SCL I2C-Compatible Serial Clock Input

15 13 SDA I2C-Compatible Serial Data I/O

16 14 V+ P osi ti ve S up p l y V ol tag e. Byp ass V + to G N D w i th a cer am i c cap aci tor of at l east 0.047µF.

— EP EP Exposed Paddle. Connect exposed pad to GND.

NAME FUNCTION

Address Inputs. Select device slave address with AD0 and AD2. Connect AD0 and
AD2 to either GND, V+, SCL, or SDA to give four logic combinations (see Table 2).

Detailed Description

MAX7319–MAX7329 Family Comparison

The MAX7319–MAX7323 family consists of five pin­compatible, eight-port expanders. Each version is opti­mized for different applications. The MAX7328 and
MAX7329 are industry-standard parts.

The MAX7324–MAX7327 family consists of four pin­compatible, 16-port expanders that integrate the func­tions of the MAX7320 and one of either MAX7319,
MAX7321, MAX7322, or MAX7323.

Functional Overview

The MAX7322 is a general-purpose port expander
operating from +1.71V to +5.5V supply that provides
four push-pull output ports with 20mA sink, 10mA
source drive capability, and four input ports that are
overvoltage protected to +6V independent of supply volt­age. The MAX7322 is rated to sink a total of 100mA and
source a total of 50mA from all four combined outputs.

The MAX7322 is set to one of 16 I

2

C slave addresses
(0x60 to 0x6F) using address inputs AD2 and AD0, and
is accessed over an I

2

C serial interface up to 400kHz.

The RST input clears the serial interface in case of a
bus lockup, terminating any serial transaction to or from
the MAX7322.

MAX7322

I2C Port Expander with

4 Push-Pull Outputs and 4 Inputs

_______________________________________________________________________________________ 5

Table 1. MAX7319–MAX7329 Family Comparison

2

C

I

PART

8-PORT EXPANDERS

MAX7319 110xxxx 8 Yes — —

MAX7320 101xxxx — — — 8

SLAVE

ADDRESS

INPUTS

INPUT

INTERRUPT

MASK

OPEN­DRAIN

OUTPUTS

PUSH-

PULL

OUTPUTS

2

C DATA

I

WRITE

<I7–I0

interrupt

mask>

<O7–O0

port

outputs>

I2C DATA

READ

<I7–I0 port

inputs>

<I7–I0

transition

flags>

<O7-O0

port

inputs>

APPLICATION

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.
Output-only versions:
8 push-pull outputs with
selectable power-up default
levels.

Push-pull outputs offer
faster rise time than open­drain outputs, and require
no pullup resistors.

MAX7322

I2C Port Expander with
4 Push-Pull Outputs and 4 Inputs

6 _______________________________________________________________________________________

Table 1. MAX7319–MAX7329 Family Comparison (continued)

2

PART

C

I

SLAVE

ADDRESS

INPUTS

INPUT

INTERRUPT

MASK

OPEN­DRAIN

OUTPUTS

PUSH-

PULL

OUTPUTS

2

C DATA

I

WRITE

I2C DATA

READ

APPLICATION

I/O versions:
8 open-drain I/O ports with
latching transition detection
interrupt and selectable
pullups.

MAX7321 110xxxx Up to 8 — Up to 8 —

MAX7322 110xxxx 4 Yes — 4

MAX7323 110xxxx Up to 4 — Up to 4 4

MAX7328
MAX7329

0100xxx
0111xxx

Up to 8 — Up to 8 —

<P7–P0

port

outputs>

<O7, O6

outputs,

I5–I2

interrupt

mask, O1,

O0

outputs>

<port

outputs>

<P7–P0

port

outputs>

<P7–P0

port
inputs>
<P7–P0

transition

flags>

<O7, O6,

I5–I2, O1,

O0 port
inputs>

<0, 0, I5–I2

transition

flags, 0, 0>

<O7, O6,

P5–P2, O1,

O0 port
inputs>

<0, 0,

P5–P2

transition

flags, 0, 0>

<P7–P0

port
inputs>

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 open­drain output to logic-high.
Transition flags identify
which inputs have changed
(even momentarily) since
the ports were last read.
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.
4 I/O, 4 output-only
versions:
4 open-drain I/O ports with
latching transition detection
interrupt and selectable
pullups.
4 push-pull outputs with
selectable power-up default
levels.
8 open-drain I/O ports with
nonlatching transition
detection interrupt and
pullups on all ports.

All ports power up as inputs
(or logic-high outputs).

Any port can be used as an
input by setting the open­drain output to logic-high.

MAX7322

I2C Port Expander with

4 Push-Pull Outputs and 4 Inputs

_______________________________________________________________________________________ 7

When the MAX7322 is read through the serial interface
the actual logic levels at the ports are read back.

The four input ports offer latching transition detection
functionality. All input ports are continuously monitored
for changes. An input change sets 1 of 4 flag bits that
identify the changed input(s). All flags are cleared upon
a subsequent read or write transaction to the MAX7322.

A latching interrupt output, INT, is programmed to flag
input data changes on the four input ports through an
interrupt mask register. By default, data changes on any
input port force INT to a logic low. The interrupt output
INT and all transition flags are deasserted when the
MAX7322 is next accessed through the serial interface.

Internal pullup resistors to V+ are selected by the
address select inputs, AD0 and AD2. Pullups are
enabled on the input ports in groups of two (see Table 2).

Output port power-up logic states are selected by the
address select inputs AD0 and AD2. Ports default to
logic-high or logic-low on power-up in groups of two
(see Table 2).

Initial Power-Up

On power-up, the transition detection logic is reset, and
INT is deasserted. The interrupt mask register is set to
0x3C, enabling the interrupt output for transitions on all
four input ports. The transition flags are cleared to indi­cate no data changes. The power-up default state of
the four push-pull outputs are set according to the I

2

C

slave address selection inputs, AD0 and AD2 (Table 2).

Power-On Reset (POR)

The MAX7322 contains an integral POR circuit that
ensures all registers are reset to a known state on

power-up. When V+ rises above V

POR

(1.6V max), the
POR circuit releases the registers and 2-wire interface
for normal operation. When V+ drops to less than V

POR

,
the MAX7322 resets all register contents to the POR
defaults (Table 2).

RST

Input

The active-low RST input operates as a reset that voids
any current I2C transaction involving the MAX7322,
forcing the MAX7322 into the I2C STOP condition. The
reset action does not clear the interrupt output (INT).

Standby Mode

When the serial interface is idle, the MAX7322 automat­ically enters standby mode, drawing minimal supply
current.

Slave Address and Input Pullup

Selection/Default Logic State

Address inputs AD0 and AD2 determine the MAX7322
slave address, select which inputs have pullup resis­tors and set the default logic state for outputs. Pullups
are enabled on the input ports in groups of two (see
Table 2). The MAX7319, MAX7321, MAX7322, and
MAX7323 use a different range of slave addresses
(110xxxx) than the MAX7320 (101xxxx).

The MAX7322 slave address is determined on each I2C
transmission, regardless of whether the transmission is
actually addressing the MAX7322. The MAX7322 distin­guishes whether address inputs AD2 and AD0 are con­nected to SDA or SCL instead of fixed logic levels V+ or
GND during this transmission. This means that the
MAX7322 slave address can be configured dynamically
in the application without cycling the device supply.

Table 1. MAX7319–MAX7329 Family Comparison (continued)

2

C

I

PART

16-PORT EXPANDERS

MAX7324 8 Yes — 8 — —

MAX7325 Up to 8 — Up to 8 8 — —

MAX7326 4 Yes — 12 — —

MAX7327

SLAVE

ADDRESS

101xxxx

and

110xxxx

INPUTS

Up to 4 — Up to 4 12 — —

INPUT

INTERRUPT

MASK

OPEN­DRAIN

OUTPUTS

PUSH-

PULL

OUTPUTS

2

C DATA

I

WRITE

I2C DATA

READ

APPLICATION

Software equivalent to a
MAX7320 plus a MAX7319.

Software equivalent to a
MAX7320 plus a MAX7321.

Software equivalent to a
MAX7320 plus a MAX7322.

Software equivalent to a
MAX7320 plus a MAX7323.

MAX7322

I2C Port Expander with
4 Push-Pull Outputs and 4 Inputs

8 _______________________________________________________________________________________

Table 2. MAX7322 Address Map

On initial power-up, the MAX7322 cannot decode the
address inputs AD2 and AD0 fully until the first I2C
transmission. AD0 and AD2 initially appear to be con­nected to V+ or GND. This is important because the
address selection determines the power-up logic state,
and whether pullups are enabled. However, at power­up, the I2C SDA and SCL bus interface lines are high
impedance at the pins of every device (master or slave)
connected to the bus, including the MAX7322. This is
guaranteed as part of the I2C specification. Therefore,
address inputs AD2 and AD0 that are connected to
SDA or SCL normally appear at power-up to be connect­ed to V+. The port selection logic uses AD0 to select
whether pullups are enabled for ports I2 and I3, and to
set the initial logic state for ports O0 and O1. AD2
selects whether pullups are enabled for ports I4 and I5
and sets the internal logic state for ports O6 and O7. The
rule is that a logic-high, SDA, or SCL connection selects
the pullups and sets the default logic state high. A logic­low deselects the pullups and sets the default logic state
low (Table 2). This means that the port configuration is
correct on power-up for a standard I2C configuration,
where SDA or SCL are pulled up to V+ by the external I2C
pullup resistors.

There are circumstances where the assumption that
SDA = SCL = V+ on power-up is not true—for example,

in applications in which there is legitimate bus activity
during power-up. Also, if SDA and SCL are terminated
with pullup resistors to a different supply voltage than
the MAX7322’s supply voltage, and if that pullup supply
rises later than the MAX7322’s supply, then SDA or
SCL may appear at power-up to be connected to GND.
In such applications, use the four address combina­tions that are selected by connecting address inputs
AD2 and AD0 to V+ or GND (shown in bold in Table 2).
These selections are guaranteed to be correct at
power-up, independent of SDA and SCL behavior. If
one of the other 12 address combinations is used, an
unexpected combination of pullups might be asserted
until the first I2C transmission (to any device, not neces­sarily the MAX7322) is put on the bus, and an unexpect­ed combination of ports may initialize as logic-low
outputs instead of inputs or logic-high outputs.

Port Inputs

Port inputs switch at CMOS logic levels as determined by
the expander’s supply voltage, and are overvoltage toler­ant to +6V, independent of the expander’s supply voltage.

Port Input Transition Detection

All four input ports are monitored for changes since the
expander was last accessed through the serial inter­face. The state of the I/O ports is stored in an internal

PIN

CONNECTION

AD2 AD0 A6A5A4A3A2A1A0O7O6I5I4I3I2O1 O0O7O6I5I4I3I2O1O0

SCLGND110000011 00 YY——

SCL V+ 110000111 1 1 YYYY

SCL SCL 1 1 0 0 0 1 0 1 1 1 1 Y Y Y Y

SCL SDA 1 1 0 0 0 1 1 1 1 1 1 Y Y Y Y

SDAGND110010011 00 YY——

SDA V+ 110010111 1 1 YYYY

SDA SCL 1 1 0 0 1 1 0 1 1 1 1 Y Y Y Y

SDA SDA 1 1 0 0 1 1 1 1 1 1 1 Y Y Y Y

GNDGND110100000 0 0 ————

GND V+ 110100100 1 1 ——YY

GNDSCL110101000 11 ——YY

GNDSDA110101100 11 ——YY

V+ GND110110011 0 0 YY——

V+ V+ 110110111 1 1 YYYY

V+ SCL 110111011 1 1 YYYY

V+ SDA110111111

DEVICE ADDRESS OUTPUTS POWER—UP DEFAULT

Inputs

11

40kΩ INPUT PULLUPS

ENABLED

Pullups are not enabled for push-pull outputs

YYYY

Pullups are not enabled for push-pull outputs

MAX7322

I2C Port Expander with

4 Push-Pull Outputs and 4 Inputs

_______________________________________________________________________________________ 9

“snapshot” register for transition monitoring. The snap­shot is continuously compared with the actual input
conditions, and if a change is detected for any port
input, then an internal transition flag is set for that port,
and INT is asserted to signal a state change. The four
port inputs are sampled (internally latched into the
snapshot register) and the old transition flags cleared
during the I2C acknowledge of every MAX7322 read
and write access. The previous port transition flags are
read through the serial interface as the second byte of
a 2-byte read sequence.

A long read sequence (more than 2 bytes) can be used
to poll the expander continuously without the overhead
of resending the slave address. If more than 2 bytes
are read from the expander, the expander repeatedly
returns the input port data alternating with the transition
flags. The inputs are repeatedly resampled and the
transition flags repeatedly reset for each pair of bytes
read. All changes that occur during a long read
sequence are detected and reported.

The MAX7322 includes a 4-bit interrupt mask register
that selects which inputs generate an interrupt upon
change. Each input’s transition flag is set when its input
changes, independent of the interrupt mask register
settings. The interrupt mask register allows the proces­sor to be interrupted for critical events, while the inputs
and the transition flags can be polled periodically to
detect less-critical events.

The INT output is not reasserted during a read sequence
to avoid recursive reentry into an interrupt service rou­tine. Instead, if a data change occurs that would normal­ly cause the INT output to be set, the INT assertion is
delayed until the STOP condition. INT is not reasserted
upon a STOP condition if the changed input data is
read before the STOP occurs. The INT logic ensures

that unnecessary interrupts are not asserted, yet data
changes are detected and reported no matter when the
change occurs.

Transition Detection Masks

The transition detection logic incorporates a change
flag and an interrupt mask bit for each of the four input
ports. The four change flags can be read through the
serial interface, and the 4-bit interrupt mask is set
through the serial interface.

Each port’s change flag is set when that port’s input
changes, and the change flag remains set even if the
input returns to its original state. The port’s interrupt
mask determines whether a change on that input port
generates an interrupt. Enable interrupts for high-priori­ty inputs using the interrupt mask. The interrupt allows
the system to respond quickly to changes on these
inputs. Poll the MAX7322 periodically to monitor less­important inputs. The change flags indicate whether a
permanent or transient change has occurred on any
input since the MAX7322 was last accessed.

Port Outputs

Write one byte to the MAX7322 to set the output port
levels for the four push-pull outputs, and the interrupt
mask for the four inputs simultaneously.

Serial Interface

Serial Addressing

The MAX7322 operates as a slave that sends and
receives data through an I2C interface. The interface
uses a serial-data line (SDA) and a serial-clock line (SCL)
to achieve bidirectional communication between mas­ter(s) and slave(s). The master initiates all data transfers
to and from the MAX7322 and generates the SCL clock
that synchronizes the data transfer (Figure 1).

Figure 1. 2-Wire Serial Interface Timing Details

SDA

t

LOW

SU,DAT

t

HIGH

t

R

t

F

t

SCL

t

HD,STA

START CONDITION

t

HD,DAT

t

SU,STA

REPEATED START CONDITION

t

HD,STA

t

SU,STO

STOP

CONDITION

t

BUF

START

CONDITION

SDA operates as both an input and an open-drain out­put. A pullup resistor, typically 4.7kΩ, is required on
SDA. SCL operates only as an input. A pullup resistor,
typically 4.7kΩ, is required on SCL if there are multiple
masters on the 2-wire interface, or if the master in a sin­gle-master system has an open-drain SCL output.

Each transmission consists of a START condition sent
by a master, followed by the MAX7322’s 7-bit slave
address plus R/W bit, one or more data bytes, and
finally a STOP condition (Figure 2).

START and STOP Conditions

Both SCL and SDA remain high when the interface is
not busy. A master signals the beginning of a transmis­sion with a START (S) condition by transitioning SDA
from high to low while SCL is high. When the master
has finished communicating with the slave, the master
issues a STOP (P) condition by transitioning SDA from
low to high while SCL is high. The bus is then free for
another transmission (Figure 2).

Bit Transfer

One data bit is transferred during each clock pulse.
The data on SDA must remain stable while SCL is high
(Figure 3).

Acknowledge

The acknowledge bit is a clocked 9th bit the recipient
uses to acknowledge receipt of each byte of data
(Figure 4). Each byte transferred effectively requires 9
bits. The master generates the 9th clock pulse, and the
recipient pulls down SDA during the acknowledge
clock pulse, such that the SDA line is stable low during
the high period of the clock pulse. When the master is
transmitting to the MAX7322, the MAX7322 generates
the acknowledge bit because the device is the recipi­ent. When the MAX7322 is transmitting to the master,
the master generates the acknowledge bit because the
master is the recipient.

MAX7322

I2C Port Expander with
4 Push-Pull Outputs and 4 Inputs

10 ______________________________________________________________________________________

Figure 3. Bit Transfer

Figure 4. Acknowledge

Figure 2. START and STOP Conditions

SDA

SCL

DATA LINE STABLE;

DATA VALID

CHANGE OF DATA

ALLOWED

SDA

SCL

SP

START

CONDITION

STOP

CONDITION

START

CONDITION

SCL

SDA BY

TRANSMITTER

SDA BY

RECEIVER

S

CLOCK PULSE

FOR ACKNOWLEDGMENT

12 89

MAX7322

I2C Port Expander with

4 Push-Pull Outputs and 4 Inputs

______________________________________________________________________________________ 11

Slave Address

The MAX7322 has a 7-bit-long slave address (Figure 5).
The eighth bit following the 7-bit slave address is the R/W
bit. It is low for a write command, and high for a read
command.

The first (A6), second (A5), and third (A4) bits of the
MAX7322 slave address are always 1, 1, and 0.
Connect AD2 and AD0 to GND, V+,SDA, or SCL to
select slave address bits A3, A2, A1, and A0. The
MAX7322 has 16 possible slave addresses (Table 2),
allowing up to 16 MAX7322 devices on an I

2

C bus.

Accessing the MAX7322

The MAX7322 is accessed through an I

2

C interface.

The transition flags are cleared, and INT is deasserted
each time the device acknowledges the I

2

C slave

address.

A single-byte read from the MAX7322 returns the sta­tus of the four input ports and the four output ports
(read back as inputs).

A 2-byte read returns the status of the four input ports
and the four output ports (as for a single-byte read), fol­lowed by the transition flags for the four input ports.

A multibyte read (more than 2 bytes before the I

2

C
STOP bit) repeatedly returns the port data, alternating
with the transition flags. As the data is resampled for
each transmission, and the transition flags are reset
each time, a multibyte read continuously returns the
current data and identifies any changing ports.

If a port data change occurs during the read sequence,
INT is reasserted after the I2C STOP bit. The MAX7322
does not generate another interrupt during a single­byte or multibyte read.

Port data is sampled during the preceding I2C
acknowledge bit (the acknowledge bit for the I

2

C slave

address in the case of a single-byte or 2-byte read).

A single-byte write to the MAX7322 sets the logic state
of the four output ports and the 4-bit interrupt mask
resistor, and clears both the internal transition flags and
the INT output when the device acknowledges the
slave address byte.

A multibyte write to the MAX7322 repeatedly sets the
logic state of the four output ports and the 4-bit inter­rupt mask register.

Figure 5. Slave Address

.

SDA

SCL

11

MSB

0

A3

A2 A1 A0

LSB

R/W

ACK

MAX7322

I2C Port Expander with
4 Push-Pull Outputs and 4 Inputs

12 ______________________________________________________________________________________

Figure 7. Reading from the MAX7322 (2 Data Bytes)

Reading from the MAX7322

A read from the MAX7322 starts with the master trans­mitting the MAX7322’s slave address with the R/W bit
set high. The MAX7322 acknowledges the slave
address, and samples the ports during the acknowl­edge bit. INT deasserts during the slave address
acknowledge.

Typically, the master reads one or two bytes from the
MAX7322, each byte being acknowledged by the mas­ter upon reception with the exception of the last byte.

When the master reads one byte from the MAX7322
and subsequently issues a STOP condition (Figure 6),

the MAX7322 transmits the current port data, clears the
change flags, and restarts the transition detection. INT
deasserts during the slave address acknowledge. The
new snapshot data is the current input port data trans­mitted to the master, so any input port changes that
occur during the transmission are detected. INT
remains high until the STOP condition.

The master can read two bytes from the MAX7322 and
then issue a STOP condition (Figure 7). In this case, the
MAX7322 transmits the current port data, followed by
the change flags. The change flags are then cleared,
and transition detection restarts. INT deasserts during
the slave address acknowledge. The new snapshot

Figure 6. Reading from the MAX7322 (1 Data Byte)

S = START CONDITION
P = STOP CONDITION
SHADED = SLAVE TRANSMISSION
N = NOT ACKNOWLEDGE

MAX7322 SLAVE ADDRESS

t

IV

S

110 A

SCL

PORTS

INT OUTPUT

R/W

PORTS

O6

O7

1

PORT SNAPSHOT

t

PH

t

IR

INT REMAINS HIGH UNTIL STOP CONDITION

O1

I2I3I4I5

PORT SNAPSHOT

ACKNOWLEDGE

O0

FROM MAX7322

D0D1D2D3D4D5D6D7

t

PSU

N

P

t

IP

S = START CONDITION
P = STOP CONDITION
SHADED = SLAVE TRANSMISSION
N = NOT ACKNOWLEDGE

SCL

PORTS

t

IV

INT OUTPUT

O7

MAX7322 SLAVE ADDRESSS110

R/W

1

A

PORT SNAPSHOT

t

PH

t

IR

PORT INPUTS INTERRUPT FLAGS

O6

INT REMAINS HIGH UNTIL STOP CONDITION

I1

I2I3I4I5

PORT SNAPSHOT

O0

0

AD0D1D2D3D4D5D6D7

D7 D6 D5 D4 D3 D2 D1 D0

t

PSU

0

F2F3F4F5

PORT SNAPSHOT

0

ACKNOWLEDGE
FROM MAX7322

P

N

t

IP

0

MAX7322

I2C Port Expander with

4 Push-Pull Outputs and 4 Inputs

______________________________________________________________________________________ 13

data is the current port data transmitted to the master,
so any input port changes occurring during the trans­mission are detected. INT remains high until the STOP
condition.

Writing to the MAX7322

A write to the MAX7322 starts with the master transmit­ting the MAX7322’s slave address with the R/W bit set
low. The MAX7322 acknowledges the slave address,
and samples the ports (takes a snapshot) during
acknowledge. INT deasserts during the slave acknowl­edge. The master proceeds to transmit 1 or more bytes
of data. The MAX7322 acknowledges these subse­quent bytes of data and updates the four output ports
and the 4-bit interrupt mask register with each new byte
until the master issues a STOP condition (Figure 8).

Applications Information

Port Input and I2C Interface Level

Translation from Higher or Lower

Logic Voltages

The MAX7322’s SDA, SCL, AD0, AD2, input RST, INT,
and input ports I2–I5 are overvoltage protected to +6V
independent of V+. This allows the MAX7322 to operate
from a lower supply voltage, such as +3.3V, while the
I

2

C interface and/or some of the four input ports are dri-

ven from a higher logic level, such as +5V.

The MAX7322 can operate from a higher supply volt­age, such as +3V, while the I2C interface and/or some
of the four input ports I2–I5 are driven from a lower
logic level, such as +2.5V. Apply a minimum voltage of

0.7 x V+ to assert a logic-high on any input. For exam­ple, a MAX7322 operating from a +5V supply may not
recognize a +3.3V nominal logic-high. One solution for
input-level translation is to drive the MAX7322 inputs
from open-drain outputs. Use a pullup resistor to V+ or
a higher supply to ensure a high logic voltage of
greater than 0.7 x V+.

Figure 8. Writing to the MAX7322

SCL

12345678

SLAVE ADDRESS

DATA TO INTERRUPT MASK DATA TO INTERRUPT MASK

S0

SDA

START CONDITION R/W ACKNOWLEDGE

INTERNAL WRITE

TO PORT

DATA OUT

FROM PORT

S = START CONDITION
P = STOP CONDITION
SHADED = SLAVE TRANSMISSION
N = NOT ACKNOWLEDGE

AAA

FROM SLAVE

DATA 1 DATA 2

ACKNOWLEDGE
FROM SLAVE

t

PV

t

PV

ACKNOWLEDGE
FROM SLAVE

DATA 2 VALIDDATA 1 VALID

Port Structures

Each of the four output ports O0, O1, O6, and O7 has
protection diodes to V+ and to GND (Figure 9). When a

port output is driven to a voltage lower than GND, the
appropriate protection diode clamps the output to a
diode drop above V+ or below GND. When the
MAX7322 is powered down (V+ = 0), each output port
appears as a diode clamp to GND (Figure 9).

Each of the four input ports I2–I5 has a protection diode
to GND (Figure 10). When a port input is driven to a
voltage lower than GND, the protection diode will
clamp the input to a diode drop below GND.

Each of the four inputs ports I2–I5 also has a 40kΩ (typ)
pullup resistor that can be enabled or disabled. When a
port is driven to a voltage higher than V+, the body
diode of the pullup enable switch conducts and the
40kΩ pullup resistor is enabled. When the MAX7322 is
powered down (V+ = 0), each input port appears as a
40kΩ pullup resistor in series with a diode connected to
zero. Input ports are protected to +6V under any of
these circumstances (Figure 10).

Driving LED Loads

When driving LEDs from one of the four output ports
O0, O1, O6, or O7, a resistor must be connected in
series with the LED to limit the LED current to no more
than 20mA. Connect the LED cathode to the MAX7322
port, and the LED anode to V+ through the series cur­rent-limiting resistor, R

LED

. Set the port output low to
light the LED. Choose the resistor value according to
the following formula:

R

LED

= (V

SUPPLY

- V

LED

- VOL) / I

LED

where:

R

LED

is the resistance of the resistor in series with the

LED (Ω).

V

SUPPLY

is the supply voltage used to drive the

LED (V).

V

LED

is the forward voltage of the LED (V).

VOLis the output low voltage of the MAX7322 when
sinking I

LED

(V).

I

LED

is the desired operating current of the LED (A).

For example, to operate a 2.2V red LED at 10mA from a
+5V supply:

R

LED

= (5 - 2.2 - 0.07) / 0.010 = 270Ω

Driving Load Currents Higher than 20mA

The MAX7322 can be used to drive loads, such as
relays, that draw more than 20mA by paralleling out­puts. Use at least one output per 20mA of load current;
for example, a 5V 330mW relay draws 66mA, and

therefore, requires all four paralleled outputs. Any com­bination of outputs can be used as part of a load-shar­ing design, because any combination of ports can be
set or cleared at the same time by writing to the
MAX7322. Do not exceed a total sink current of 100mA
for the device.

The MAX7322 must be protected from the negative
voltage transient generated when switching off induc­tive loads (such as relays), by connecting a reverse­biased diode across the inductive load. Choose the
peak current for the diode to be greater than the induc­tive load’s operating current.

Power-Supply Considerations

The MAX7322 operates with a supply voltage of
+1.71V to +5.5V over the -40°C to +125°C temperature
range. Bypass the supply to GND with a ceramic
capacitor of at least 0.047µF as close to the device as
possible. For the TQFN version, additionally connect
the exposed pad to GND.

MAX7322

I2C Port Expander with
4 Push-Pull Outputs and 4 Inputs

14 ______________________________________________________________________________________

Figure 10. MAX7322 Input Port Structure

Figure 9. MAX7322 Push-Pull Output Port Structure

V+V+

MAX7322

PORTS
O0, O1, O6, O7

OUTPUT

V+

V+

PULLUP

ENABLE

INPUT

40kΩ

MAX7322

PORTS

I2–I5

MAX7322

I2C Port Expander with

4 Push-Pull Outputs and 4 Inputs

______________________________________________________________________________________ 15

Pin Configurations (continued)

Chip Information

PROCESS: BiCMOS

Typical Application Circuit

Functional Diagram

AD0

AD2

I/O

PORTS

SDA

SCL

RST

INPUT

FILTER

POWER-

ON RESET

I2C

CONTROL

MAX7322

3.3V

O0
O1
I2
I3
I4
I5
O6
O7

INT

μC

SCL

SDA

RST

INT

SCL

SDA

RST

INT

AD0
AD2

V+

MAX7322

GND

0.047μF

O7
O6

I5
I4
I3

I2
O1
O0

OUTPUT
OUTPUT

INPUT
INPUT
INPUT

INPUT
OUTPUT
OUTPUT

TOP VIEW

RST

+

1

2

3

MAX7322

4

O0

O1

5

I2

6

I3

7

8

16

V+

15

SDA

14

SCL

13

INT

12

O7

O6

11

10

I5

9

I4

AD0

AD2

GND

QSOP

MAX7322

I2C Port Expander with
4 Push-Pull Outputs and 4 Inputs

16 ______________________________________________________________________________________

Package Information

(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information,
go to www.maxim-ic.com/packages

.)

MARKING

E/2

D/2

D

0.10 C 0.08 C

AAAA

L

(NE - 1) X e

E2/2

E2

D2/2

D2

b

0.10 M C A B

C
L

L

e

12x16L QFN THIN.EPS

E

(ND - 1) X e

e

C

L

k

C

L

C

L

A

A2

A1

L

e

PACKAGE OUTLINE
8, 12, 16L THIN QFN, 3x3x0.8mm

21-0136

1

I

2

MAX7322

I2C Port Expander with

4 Push-Pull Outputs and 4 Inputs

______________________________________________________________________________________ 17

Package Information (continued)

(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information,
go to www.maxim-ic.com/packages

.)

PKG

REF. MIN.

8L 3x3

MIN.

NOM. M

AX.

A

0.70 0.75 0.80

b

0.25 0.30 0.35

D

2.90

E

2.90 3.00 3.10

e

0.35

L

ND

NE

0

A1

A2

k

0.25

3.00 3.10

0.65 BSC.

0.55 0.75

8

2

2

0.02

0.20 REF

0.70

0.20

2.90

2.90

0.45

0.05

0

-

-

0.25

NOTES:

1. DIMENSIONING & TOLERANCING CONFORM TO ASME Y14.5M-1994.

2. ALL DIMENSIONS ARE IN MILLIMETERS. ANGLES ARE IN DEGREES.

3. N IS THE TOTAL NUMBER OF TERMINALS.

4. THE TERMINAL #1 IDENTIFIER AND TERMINAL NUMBERING CONVENTION SHALL CONFORM TO
JESD 95-1 SPP-012. DETAILS OF TERMINAL #1 IDENTIFIER ARE OPTIONAL, BUT MUST BE LOCATED
WITHIN THE ZONE INDICATED. THE TERMINAL #1 IDENTIFIER MAY BE EITHER A MOLD OR
MARKED FEATURE.

5. DIMENSION b APPLIES TO METALLIZED TERMINAL AND IS MEASURED BETWEEN 0.20 mm AND 0.25 mm
FROM TERMINAL TIP.

6. ND AND NE REFER TO THE NUMBER OF TERMINALS ON EACH D AND E SIDE RESPECTIVELY.

7. DEPOPULATION IS POSSIBLE IN A SYMMETRICAL FASHION.

8. COPLANARITY APPLIES TO THE EXPOSED HEAT SINK SLUG AS WELL AS THE TERMINALS.

9. DRAWING CONFORMS TO JEDEC MO220 REVISION C.

10. MARKING IS FOR PACKAGE ORIENTATION REFERENCE ONLY.

11. NUMBER OF LEADS SHOWN ARE FOR REFERENCE ONLY.

12. WARPAGE NOT TO EXCEED

12L 3x3

NOM. MAX. NOM.

0.75

0.25

0.30

3.00

3.00

0.50 BSC.

0.55

12N

3

3

0.02

0.20 REF

-

0.10mm.

MIN. MAX.

0.70

0.80

0.20

2.90

3.10

3.10

2.90

0.65

0.30

0.05

-

0.25

16L 3x3

0.50 BSC.

040.02

0.20 REF

0.75

0.25

3.00

3.00

0.40

EXPOSED PAD VARIATIONS

PKG.

0.80

0.30

3.10

3.10

0.50

16

4

0.05

-

-

CODES

TQ833-1 1.250.25 0.70 0.35 x 45° WEEC1.250.700.25

T1233-1

3

T1233-

T1233-4

T1633-2 0.95

T1633F-3

T1633FH-3 0.65 0.80 0.95

T1633-4 0.95

T1633-5 0.95

D2

MIN.

0.95

0.95

0.95

0.65

MAX.

NOM.

1.25

1.10

1.25

1.10

1.251.10

1.25

1.10

0.95

0.80

1.10 1.25 0.95 1.10

1.25

1.10

E2

NOM.

MIN.

0.95

0.95 1.10 0.35 x 45°1.25 WEED-1

0.95

0.65

0.65 0.80

MAX.

1.10

1.25

1.100.95

1.10

1.25

0.80

0.95

0.95

1.25

1.25

1.10

PACKAGE OUTLINE
8, 12, 16L THIN QFN, 3x3x0.8mm

ID

PIN

0.35 x 45°

0.35 x 45°

0.35 x 45°

0.225 x 45°

0.225 x 45°

0.35 x 45°

0.35 x 45°

JEDEC

WEED-1

WEED-11.25

WEED-2

WEED-2

WEED-2

WEED-2

WEED-20.95

21-0136

2

I

2

MAX7322

I2C Port Expander with
4 Push-Pull Outputs and 4 Inputs

Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.

18 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600

© 2006 Maxim Integrated Products is a registered trademark of Maxim Integrated Products, Inc.

Package Information (continued)

(The package drawing(s) in this data sheet may not reflect the most current specifications. For the latest package outline information,
go to www.maxim-ic.com/packages

.)

Revision History

Pages changed at Rev 1: 1–18

QSOP.EPS

PACKAGE OUTLINE, QSOP .150", .025" LEAD PITCH

1

21-0055

F

1