MAX7322

MAX7322
19-3787; Rev 1; 9/06
KIT
ATION
EVALU
E
L
B
AVAILA
I2C Port Expander with
4 Push-Pull Outputs and 4 Inputs
Applications
Cell Phones
SAN/NAS
Servers
Ordering Information
PART
TEMP
RANGE
PINPACKAGE
MAX7322AEE+
-40°C to
+125°C
16 QSOP
MAX7322ATE+
-40°C to
+125°C
16 TQFN-EP*
(3mm x 3mm)
—
—
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
—
O6
—
Up to 8
O7
Yes
INT
8
MAX7321
I4
6
GND
5
I3
MAX7322
AD0 15
2
3
4
O1
I2
AD2
1
O0
*EP
+
OPENPUSH-PULL
DRAIN
OUTPUTS
OUTPUTS
MAX7319
MAX7320
7
T1633-4
INTERRUPT
MASK
9
V+ 14
ADD
INPUTS
10
I5
E16-4
PART
11
8
—
Selector Guide
12
SDA 13
PKG
CODE
*EP = Exposed paddle.
SCL
TOP VIEW
TOP
MARK
+Denotes lead-free package.
Notebooks
Satellite Radio
Automotive
Pin Configurations
RST 16
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
—
—
TQFN
(3mm x 3mm)
Pin Configurations continued at end of data sheet.
Typical Application Circuit and Functional Diagram appear
at end of data sheet.
________________________________________________________________ Maxim Integrated Products
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.
1
MAX7322
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
I2C communication to or from the MAX7322.
The MAX7322 uses two address inputs with four-level
logic to allow 16 I2C 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.
MAX7322
I2C Port Expander with
4 Push-Pull Outputs and 4 Inputs
ABSOLUTE MAXIMUM RATINGS
(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 (TA = +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
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.
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
Operating Supply Voltage
Power-On Reset Voltage
Standby Current
(Interface Idle)
Supply Current
(Interface Running)
SYMBOL
CONDITIONS
V+
MIN
1.71
1.6
V
ISTB
0.6
1.5
µA
I+
fSCL = 400kHz; other digital inputs at V+
23
55
µA
VIL
Input Leakage Current
SDA, SCL, AD0, AD2, RST, I2–I5
IIH, IIL
V+ < 1.8V
0.8 x V+
V+ ≥ 1.8V
0.7 x V+
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
-0.2
Input Capacitance
SDA, SCL, AD0, AD2, RST, I2–I5
+0.2
10
VOL
90
180
V+ = +2.5V, ISINK = 10mA
110
210
V+ = +3.3V, ISINK = 15mA
130
230
140
250
VOH
V+ = +1.71V, ISOURCE = 2mA
V+ - 250 V+ - 30
V+ = +2.5V, ISOURCE = 5mA
V+ - 360 V+ - 70
V+ = +3.3V, ISOURCE = 5mA
V+ - 260 V+ - 100
V+ = +5V, ISOURCE = 10mA
V+ - 360 V+ - 120
Output Low Voltage SDA
VOLSDA
ISINK = 6mA
Output Low Voltage INT
VOLINT
ISINK = 5mA
RPU
25
V
µA
pF
V+ = +1.71V, ISINK = 5mA
V+ = +5V, ISINK = 20mA
2
V
SCL and SDA and other digital inputs at
V+
Input Low Voltage
SDA, SCL, AD0, AD2, RST, I2–I5
Port Input Pullup Resistor
UNITS
5.50
V+ falling
VIH
Output High Voltage
O0, O1, O6, O7
MAX
VPOR
Input High Voltage
SDA, SCL, AD0, AD2, RST, I2–I5
Output Low Voltage
O0, O1, O6, O7
TYP
mV
mV
250
mV
130
250
mV
40
55
kΩ
_______________________________________________________________________________________
I2C Port Expander with
4 Push-Pull Outputs and 4 Inputs
(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
4
µs
Port Output Data Valid
tPPV
CL ≤ 100pF
Port Input Setup Time
tPSU
CL ≤ 100pF
0
µs
Port Input Hold Time
tPH
CL ≤ 100pF
4
µs
INT Input Data Valid Time
tIV
CL ≤ 100pF
4
µs
INT Reset Delay Time from STOP
tIP
CL ≤ 100pF
4
µs
INT Reset Delay Time from
Acknowledge
tIR
CL ≤ 100pF
4
µs
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)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
400
kHz
Serial Clock Frequency
fSCL
Bus Free Time Between a STOP
and a START Condition
tBUF
1.3
µs
Hold Time (Repeated) START
Condition
tHD, STA
0.6
µs
Repeated START Condition
Setup Time
tSU, STA
0.6
µs
STOP Condition Setup Time
tSU, STO
Data Hold Time
tHD, DAT
Data Setup Time
tSU, DAT
100
ns
tLOW
tHIGH
1.3
0.7
µs
µs
SCL Clock Low Period
SCL Clock High Period
0.6
µs
(Note 2)
0.9
µs
Rise Time of Both SDA and SCL
Signals, Receiving
tR
(Notes 3, 4)
20 +
0.1Cb
300
ns
Fall Time of Both SDA and SCL
Signals, Receiving
tF
(Notes 3, 4)
20 +
0.1Cb
300
ns
Fall Time of SDA, Transmitting
tF,TX
(Notes 3, 4)
20 +
0.1Cb
250
ns
Pulse Width of Spike Suppressed
tSP
(Note 5)
Capacitive Load for Each Bus
Line
Cb
(Note 3)
RST Pulse Width
tW
500
ns
tRST
1
µs
RST Rising to START Condition
Setup Time
50
ns
400
pF
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 VIL of the SCL signal) in order to
bridge the undefined region of SCL’s falling edge.
Note 3: Guaranteed by design.
Note 4: Cb = total capacitance of one bus line in pF. tR and tF measured between 0.3 x V+ and 0.7 x V+ with ISINK ≤ 6mA.
Note 5: Input filters on the SDA and SCL inputs suppress noise spikes less than 50ns.
_______________________________________________________________________________________
3
MAX7322
PORT AND INTERRUPT INT TIMING CHARACTERISTICS
Typical Operating Characteristics
(TA = +25°C, unless otherwise noted.)
1.4
1.2
V+ = +5.0V
1.0
V+ = +3.3V
V+ = +2.5V
0.8
0.6
0.4
fSCL = 400kHz
V+ = +5.0V
50
SUPPLY CURRENT (μA)
V+ = +1.71V
40
V+ = +3.3V
30
20
V+ = +2.5V
10
0.2
V+ = +1.71V
0
0
-40 -25 -10 5 20 35 50 65 80 95 110 125
-40 -25 -10 5 20 35 50 65 80 95 110 125
TEMPERATURE (°C)
TEMPERATURE (°C)
OUTPUT VOLTAGE LOW
vs. TEMPERATURE
OUTPUT VOLTAGE HIGH
vs. TEMPERATURE
6
MAX7322 toc03
0.40
0.30
0.25
V+ = +3.3V
ISINK = 15mA
0.20
V+ = +5.0V
ISINK = 20mA
0.15
0.10
0.05
V+ = +1.71V
ISINK = 5mA
0
V+ = +2.5V
ISINK = 10mA
V+ = +5.0V
ISOURCE = 10mA
5
OUTPUT VOLTAGE HIGH (V)
0.35
MAX7322 toc04
STANDBY CURRENT (μA)
1.6
MAX7322 toc01
fSCL = 0kHz
1.8
60
MAX7322 toc02
SUPPLY CURRENT vs. TEMPERATURE
STANDBY CURRENT vs. TEMPERATURE
2.0
OUTPUT VOLTAGE LOW (V)
MAX7322
I2C Port Expander with
4 Push-Pull Outputs and 4 Inputs
V+ = +3.3V
ISOURCE = 5mA
4
3
2
V+ = +1.71V
ISOURCE = 2mA
1
V+ = +2.5V
ISOURCE = 5mA
0
-40 -25 -10 5 20 35 50 65 80 95 110 125
TEMPERATURE (°C)
-40 -25 -10 5 20 35 50 65 80 95 110 125
TEMPERATURE (°C)
Pin Description
PIN
NAME
FUNCTION
QSOP
TQFN
1, 3
15, 1
AD0, AD2
2
16
RST
4, 5, 11, 12,
2, 3, 9, 10
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
4
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).
Reset Input. Active Low. Drive RST low to clear the 2-wire interface.
O0, O1, O6, O7 Push-Pull Output Ports
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+
Positive Supply Voltage. Bypass V+ to GND with a ceramic capacitor of at least 0.047µF.
—
EP
EP
Exposed Paddle. Connect exposed pad to GND.
_______________________________________________________________________________________
I2C Port Expander with
4 Push-Pull Outputs and 4 Inputs
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 I2C slave addresses
(0x60 to 0x6F) using address inputs AD2 and AD0, and
is accessed over an I2C 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.
Table 1. MAX7319–MAX7329 Family Comparison
PART
INPUT
OPENI2C
SLAVE
DRAIN
INPUTS INTERRUPT
ADDRESS
MASK
OUTPUTS
PUSHPULL
OUTPUTS
I2C DATA
WRITE
I2C DATA
READ
APPLICATION
8-PORT EXPANDERS
Input-only versions:
8 input ports with
programmable latching
transition detection interrupt
and selectable pullups.
MAX7319
110xxxx
8
Yes
—
—
<I7–I0
interrupt
mask>
MAX7320
101xxxx
—
—
—
8
<O7–O0
port
outputs>
<I7–I0 port
inputs>
<I7–I0
transition
flags>
<O7-O0
port
inputs>
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.
_______________________________________________________________________________________
5
MAX7322
Detailed Description
MAX7322
I2C Port Expander with
4 Push-Pull Outputs and 4 Inputs
Table 1. MAX7319–MAX7329 Family Comparison (continued)
PART
INPUT
OPENI2C
SLAVE
DRAIN
INPUTS INTERRUPT
ADDRESS
MASK
OUTPUTS
PUSHPULL
OUTPUTS
I2C DATA
WRITE
I2C DATA
READ
APPLICATION
I/O versions:
8 open-drain I/O ports with
latching transition detection
interrupt and selectable
pullups.
MAX7321
MAX7322
110xxxx
110xxxx
Up to 8
4
—
Yes
Up to 8
—
—
<P7–P0
port
outputs>
<P7–P0
port
inputs>
<P7–P0
transition
flags>
4
<O7, O6
outputs,
I5–I2
interrupt
mask, O1,
O0
outputs>
<O7, O6,
I5–I2, O1,
O0 port
inputs>
<0, 0, I5–I2
transition
flags, 0, 0>
MAX7323
110xxxx
Up to 4
—
Up to 4
4
<port
outputs>
<O7, O6,
P5–P2, O1,
O0 port
inputs>
<0, 0,
P5–P2
transition
flags, 0, 0>
MAX7328
MAX7329
0100xxx
0111xxx
Up to 8
—
Up to 8
—
<P7–P0
port
outputs>
<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.
6
_______________________________________________________________________________________
I2C Port Expander with
4 Push-Pull Outputs and 4 Inputs
MAX7322
Table 1. MAX7319–MAX7329 Family Comparison (continued)
PART
INPUT
OPENI2C
SLAVE
DRAIN
INPUTS INTERRUPT
ADDRESS
MASK
OUTPUTS
PUSHPULL
OUTPUTS
I2C DATA
WRITE
I2C DATA
READ
APPLICATION
16-PORT EXPANDERS
MAX7324
MAX7325
MAX7326
MAX7327
101xxxx
and
110xxxx
8
Yes
—
8
—
—
Software equivalent to a
MAX7320 plus a MAX7319.
Up to 8
—
Up to 8
8
—
—
Software equivalent to a
MAX7320 plus a MAX7321.
4
Yes
—
12
—
—
Software equivalent to a
MAX7320 plus a MAX7322.
Up to 4
—
Up to 4
12
—
—
Software equivalent to a
MAX7320 plus a MAX7323.
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 I2C
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 VPOR (1.6V max), the
POR circuit releases the registers and 2-wire interface
for normal operation. When V+ drops to less than VPOR,
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 I 2C 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.
_______________________________________________________________________________________
7
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
Table 2. MAX7322 Address Map
PIN
CONNECTION
8
DEVICE ADDRESS
40kΩ INPUT PULLUPS
ENABLED
OUTPUTS POWER—UP DEFAULT
AD0
A6
A5
A4
A3
A2
A1
A0
O7
O6
O1
O0
I5
I4 I3 I2 O1 O0
SCL
GND
1
1
0
0
0
0
0
1
1
I5
I4
I3
0
0
Y
Y
— —
SCL
V+
1
1
0
0
0
0
1
1
1
1
1
Y
Y
Y
Y
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
SDA
GND
1
1
0
0
1
0
0
1
1
0
0
Y
Y
— —
SDA
V+
1
1
0
0
1
0
1
1
1
1
1
SDA
SCL
1
1
0
0
1
1
0
1
1
1
1
SDA
SDA
1
1
0
0
1
1
1
1
1
1
1
GND
GND
1
1
0
1
0
0
0
0
0
0
0
GND
V+
1
1
0
1
0
0
1
0
0
1
1
GND
SCL
1
1
0
1
0
1
0
0
0
1
1
GND
SDA
1
1
0
1
0
1
1
0
0
1
1
V+
GND
1
1
0
1
1
0
0
1
1
0
0
Inputs
I2
O7 O6
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
—
— — —
—
— Y
Y
—
— Y
Y
—
— Y
Y
Y
Y
— —
V+
V+
1
1
0
1
1
0
1
1
1
1
1
Y
Y
Y
Y
V+
SCL
1
1
0
1
1
1
0
1
1
1
1
Y
Y
Y
Y
V+
SDA
1
1
0
1
1
1
1
1
1
1
1
Y
Y
Y
Y
_______________________________________________________________________________________
Pullups are not enabled for push-pull outputs
AD2
Pullups are not enabled for push-pull outputs
MAX7322
I2C Port Expander with
4 Push-Pull Outputs and 4 Inputs
I2C Port Expander with
4 Push-Pull Outputs and 4 Inputs
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).
SDA
tSU,STA
tSU,DAT
tLOW
tBUF
tHD,STA
tSU,STO
tHD,DAT
tHIGH
SCL
tHD,STA
tR
tF
START CONDITION
REPEATED START CONDITION
STOP
CONDITION
START
CONDITION
Figure 1. 2-Wire Serial Interface Timing Details
_______________________________________________________________________________________
9
MAX7322
“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.
MAX7322
I2C Port Expander with
4 Push-Pull Outputs and 4 Inputs
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).
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.
SDA
SCL
Bit Transfer
One data bit is transferred during each clock pulse.
The data on SDA must remain stable while SCL is high
(Figure 3).
DATA LINE STABLE; CHANGE OF DATA
DATA VALID
ALLOWED
Figure 3. Bit Transfer
CLOCK PULSE
FOR ACKNOWLEDGMENT
START
CONDITION
SDA
SCL
SCL
S
P
START
CONDITION
STOP
CONDITION
Figure 2. START and STOP Conditions
10
1
2
SDA BY
TRANSMITTER
SDA BY
RECEIVER
S
Figure 4. Acknowledge
______________________________________________________________________________________
8
9
I2C Port Expander with
4 Push-Pull Outputs and 4 Inputs
Accessing the MAX7322
The MAX7322 is accessed through an I2C 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 write to the MAX7322 repeatedly sets the
logic state of the four output ports and the 4-bit interrupt mask register.
.
SDA
1
1
0
A3
A2
A1
A0
R/W
ACK
LSB
MSB
SCL
Figure 5. Slave Address
______________________________________________________________________________________
11
MAX7322
A multibyte read (more than 2 bytes before the I2C
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 I 2 C
acknowledge bit (the acknowledge bit for the I2C 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.
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 I2C bus.
MAX7322
I2C Port Expander with
4 Push-Pull Outputs and 4 Inputs
Reading from the MAX7322
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.
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 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
PORTS
S = START CONDITION
P = STOP CONDITION
SHADED = SLAVE TRANSMISSION
N = NOT ACKNOWLEDGE
S
1
1
O6
O7
0
MAX7322 SLAVE ADDRESS
1
A
D7
R/W
I5
D6
I4
D5
I3
D4
O1
I2
D3
D2
ACKNOWLEDGE
FROM MAX7322
O0
D1
D0
N
P
PORT SNAPSHOT
PORT SNAPSHOT
SCL
tPH
PORTS
tIV
tPSU
tIR
INT OUTPUT
tIP
INT REMAINS HIGH UNTIL STOP CONDITION
Figure 6. Reading from the MAX7322 (1 Data Byte)
PORT INPUTS
S = START CONDITION
P = STOP CONDITION
SHADED = SLAVE TRANSMISSION
N = NOT ACKNOWLEDGE
S
1
1
O7
0 MAX7322 SLAVE ADDRESS 1
A
D7
R/W
O6
D6
I5
D5
PORT SNAPSHOT
I4
I3
D4
D3
INTERRUPT FLAGS
I1
I2
D2
D1
O0
D0
PORT SNAPSHOT
0
A
D7
0
D6
F5
D5
F4
D4
F3
D3
F2
D2
0
0
D1
D0
ACKNOWLEDGE
FROM MAX7322
N
P
PORT SNAPSHOT
SCL
tPH
PORTS
tPSU
tIV
INT OUTPUT
tIR
INT REMAINS HIGH UNTIL STOP CONDITION
Figure 7. Reading from the MAX7322 (2 Data Bytes)
12
______________________________________________________________________________________
tIP
I2C Port Expander with
4 Push-Pull Outputs and 4 Inputs
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).
1
SCL
2
3
4
5
6
7
S
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+.
DATA TO INTERRUPT MASK
0
START CONDITION
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
I2C interface and/or some of the four input ports are driven from a higher logic level, such as +5V.
8
SLAVE ADDRESS
SDA
Port Input and I2C Interface Level
Translation from Higher or Lower
Logic Voltages
A
DATA TO INTERRUPT MASK
A
DATA 1
A
DATA 2
ACKNOWLEDGE
FROM SLAVE
R/W ACKNOWLEDGE
FROM SLAVE
ACKNOWLEDGE
FROM SLAVE
INTERNAL WRITE
TO PORT
DATA OUT
FROM PORT
DATA 1 VALID
tPV
DATA 2 VALID
tPV
S = START CONDITION
P = STOP CONDITION
SHADED = SLAVE TRANSMISSION
N = NOT ACKNOWLEDGE
Figure 8. Writing to the MAX7322
______________________________________________________________________________________
13
MAX7322
Applications Information
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.
MAX7322
I2C Port Expander with
4 Push-Pull Outputs and 4 Inputs
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).
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.
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, RLED. Set the port output low to
light the LED. Choose the resistor value according to
the following formula:
RLED = (VSUPPLY - VLED - VOL) / ILED
where:
RLED is the resistance of the resistor in series with the
LED (Ω).
V SUPPLY is the supply voltage used to drive the
LED (V).
VLED is the forward voltage of the LED (V).
VOL is the output low voltage of the MAX7322 when
sinking ILED (V).
ILED is the desired operating current of the LED (A).
For example, to operate a 2.2V red LED at 10mA from a
+5V supply:
RLED = (5 - 2.2 - 0.07) / 0.010 = 270Ω
V+
V+
MAX7322
PORTS
O0, O1, O6, O7
OUTPUT
Figure 9. MAX7322 Push-Pull Output Port Structure
V+
V+
PULLUP
MAX7322
ENABLE
40kΩ
INPUT
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
14
Figure 10. MAX7322 Input Port Structure
______________________________________________________________________________________
PORTS
I2–I5
I2C Port Expander with
4 Push-Pull Outputs and 4 Inputs
Typical Application Circuit
3.3V
AD0
AD2
SCL
INPUT
SDA
I/O
PORTS
I2C
CONTROL
FILTER
INT
POWERON RESET
RST
O0
O1
I2
I3
I4
I5
O6
O7
0.047μF
V+
μC
SCL
SCL
SDA
SDA
RST
RST
INT
INT
O7
MAX7322
O6
I5
I4
I3
I2
AD0
AD2
GND
O1
O0
OUTPUT
OUTPUT
INPUT
INPUT
INPUT
INPUT
OUTPUT
OUTPUT
MAX7322
Chip Information
Pin Configurations (continued)
PROCESS: BiCMOS
TOP VIEW
AD0 1
+
16 V+
RST 2
15 SDA
AD2 3
14 SCL
O0 4
MAX7322
13 INT
O1 5
12 O7
I2 6
11 O6
I3 7
10 I5
GND 8
9
I4
QSOP
______________________________________________________________________________________
15
MAX7322
Functional Diagram
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.)
(NE - 1) X e
E
MARKING
12x16L QFN THIN.EPS
MAX7322
I2C Port Expander with
4 Push-Pull Outputs and 4 Inputs
E/2
D2/2
(ND - 1) X e
D/2
AAAA
e
CL
D
D2
k
CL
b
0.10 M C A B
E2/2
L
E2
0.10 C
C
L
0.08 C
C
L
A
A2
A1
L
L
e
e
PACKAGE OUTLINE
8, 12, 16L THIN QFN, 3x3x0.8mm
21-0136
16
______________________________________________________________________________________
I
1
2
I2C Port Expander with
4 Push-Pull Outputs and 4 Inputs
PKG
8L 3x3
12L 3x3
REF.
MIN. NOM. MAX.
MIN. NOM. MAX.
MIN. NOM. MAX.
A
0.70
0.75
0.80
0.70
0.75
0.80
0.70
0.75
0.80
b
0.25
0.30
0.35
0.20
0.25
0.30
0.20
0.25
0.30
D
2.90
3.00
3.10
2.90
3.00
3.10
2.90
3.00
3.10
E
2.90
3.00
3.10
2.90
3.00
3.10
2.90
3.00
3.10
e
L
0.55
0.75
0.45
0.55
0.65
0.30
0.40
N
8
12
16
ND
2
3
4
NE
2
3
4
0
A1
A2
k
0.05
0.02
0
0.20 REF
0.25
-
0.02
0.05
0
0.20 REF
-
0.25
-
EXPOSED PAD VARIATIONS
0.50 BSC.
0.50 BSC.
0.65 BSC.
0.35
16L 3x3
0.02
0.50
0.05
0.20 REF
-
0.25
-
PKG.
CODES
E2
D2
MIN.
NOM.
MAX.
MIN.
NOM.
MAX.
PIN ID
JEDEC
TQ833-1
0.25
0.70
1.25
0.25
0.70
1.25
0.35 x 45°
T1233-1
0.95
1.10
1.25
0.95
1.10
1.25
0.35 x 45°
WEEC
WEED-1
T1233-3
0.95
1.10
1.25
0.95
1.10
1.25
0.35 x 45°
WEED-1
T1233-4
0.95
1.10
1.25
0.95
1.10
1.25
0.35 x 45°
WEED-1
T1633-2
0.95
1.10
1.25
0.95
1.10
1.25
0.35 x 45°
WEED-2
T1633F-3
0.65
0.80
0.95
0.65
0.80
0.95
0.225 x 45°
WEED-2
T1633FH-3
0.65
0.80
0.95
0.65
0.80
0.95
0.225 x 45°
WEED-2
T1633-4
0.95
1.10
1.25
0.95
1.10
1.25
0.35 x 45°
WEED-2
T1633-5
0.95
1.10
1.25
0.95
1.10
1.25
0.35 x 45°
WEED-2
-
NOTES:
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
DIMENSIONING & TOLERANCING CONFORM TO ASME Y14.5M-1994.
ALL DIMENSIONS ARE IN MILLIMETERS. ANGLES ARE IN DEGREES.
N IS THE TOTAL NUMBER OF TERMINALS.
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.
DIMENSION b APPLIES TO METALLIZED TERMINAL AND IS MEASURED BETWEEN 0.20 mm AND 0.25 mm
FROM TERMINAL TIP.
ND AND NE REFER TO THE NUMBER OF TERMINALS ON EACH D AND E SIDE RESPECTIVELY.
DEPOPULATION IS POSSIBLE IN A SYMMETRICAL FASHION.
COPLANARITY APPLIES TO THE EXPOSED HEAT SINK SLUG AS WELL AS THE TERMINALS.
DRAWING CONFORMS TO JEDEC MO220 REVISION C.
MARKING IS FOR PACKAGE ORIENTATION REFERENCE ONLY.
NUMBER OF LEADS SHOWN ARE FOR REFERENCE ONLY.
WARPAGE NOT TO EXCEED 0.10mm.
PACKAGE OUTLINE
8, 12, 16L THIN QFN, 3x3x0.8mm
21-0136
I
2
______________________________________________________________________________________
2
17
MAX7322
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.)
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.)
QSOP.EPS
MAX7322
I2C Port Expander with
4 Push-Pull Outputs and 4 Inputs
PACKAGE OUTLINE, QSOP .150", .025" LEAD PITCH
21-0055
F
1
1
Revision History
Pages changed at Rev 1: 1–18
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.
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