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.
Electrical Characteristics
PARAMETER
Operating Supply Voltage
Power-On Reset Voltage
Standby Current
(Interface Idle)
Supply Current
(Interface Running)
Input High Voltage
SDA, SCL, AD0, AD2,
RST,
P0–P7
Input Low Voltage
SDA, SCL, AD0, AD2,
RST,
P0–P7
Input Leakage Current
SDA, SCL, AD0, AD2,
RST,
P0–P7
Input Capacitance
SDA, SCL, AD0, AD2,
RST,
P0–P7
(V+ = +1.71V to +5.5V, T
A
= -40°C to +125°C, unless otherwise noted. Typical values are at V+ = +3.3V, T
A
= +25°C.) (Note 1)
SYMBOL
V
+
V
POR
I
STB
I
+
V
IH
V
IL
I
IH
, I
IL
V+ falling
SCL and SDA and other digital inputs at V+
f
SCL
= 400kHz; other digital inputs at V+
V+ < 1.8V
V+ ≥ 1.8
V+ < 1.8V
V+ ≥ 1.8V
SDA, SCL, AD0, AD2,
RST,
P0–P7 at V+ or
GND, internal pullup disabled
-0.2
10
V+ = +1.71V, I
SINK
= 5mA
Output Low Voltage P0–P7
V
OL
V+ = +2.5V, I
SINK
= 10mA
V+ = +3.3V, I
SINK
= 15mA
V+ = +5V, I
SINK
= 20mA
Output Low Voltage SDA
Output Low Voltage
INT
Port Input Pullup Resistor
V
OLSDA
V
OLINT
R
PU
I
SINK
= 6mA
I
SINK
= 5mA
25
130
40
90
110
130
140
180
210
230
250
250
250
55
mV
mV
kΩ
mV
0.8 x V+
0.7 x V+
0.2 x V+
0.3 x V+
+0.2
0.6
23
CONDITIONS
MIN
1.71
TYP
MAX
5.50
1.6
1.5
55
UNITS
V
V
µA
µA
V
V
µA
pF
www.maximintegrated.com
Maxim Integrated
│
2
MAX7321
I
2
C Port Expander with 8 Open-Drain I/Os
Port and Interrupt
INT
Timing Characteristics
(V+ = +1.71V to +5.5V, T
A
= -40°C to +125°C, unless otherwise noted. Typical values are at V+ = +3.3V, T
A
= +25°C.) (Note 1)
PARAMETER
Port Output Data Valid
Port Input Setup Time
Port Input Hold Time
INT
Input Data Valid Time
INT
Reset Delay Time from STOP
INT
Reset Delay Time from
Acknowledge
SYMBOL
t
PPV
t
PSU
t
PH
t
IV
t
IP
t
IR
C
L
≤ 100pF
C
L
≤ 100pF
C
L
≤ 100pF
CL
≤ 100pF
CONDITIONS
MIN
0
4
TYP
MAX
4
UNITS
µs
µs
µs
4
4
4
µs
µs
µs
C
L
≤ 100pF
C
L
≤ 100pF
Timing Characteristics
PARAMETER
Serial-Clock Frequency
Bus Free Time Between a STOP
and a START Condition
Hold Time (Repeated) START
Condition
Repeated START Condition Setup
Time
STOP Condition Setup Time
Data Hold Time
Data Setup Time
SCL Clock Low Period
SCL Clock High Period
Rise Time of Both SDA and SCL
Signals, Receiving
Fall Time of Both SDA and SCL
Signals, Receiving
Fall Time of SDA, Transmitting
Pulse Width of Spike Suppressed
Capacitive Load for Each Bus
Line
RST
Pulse Width
RST
Rising to START Condition
Setup Time
(V+ = +1.71V to +5.5V, T
A
= -40°C to +125°C, unless otherwise noted. Typical values are at V+ = +3.3V, T
A
= +25°C.) (Note 1)
SYMBOL
f
SCL
t
BUF
t
HD, STA
t
SU, STA
t
SU, STO
t
HD, DAT
t
SU, DAT
t
HIGH
t
R
t
F
t
F,TX
t
SP
C
b
t
W
t
RST
(Notes 3, 4)
(Notes 3, 4)
(Notes 3, 4)
(Note 5)
(Note 3)
500
1
t
LOW
(Note 2)
100
1.3
0.7
20 +
0.1C
b
20 +
0.1C
b
20 +
0.1C
b
50
400
300
300
250
1.3
0.6
0.6
0.6
0.9
CONDITIONS
MIN
TYP
MAX
400
UNITS
kHz
µs
µs
µs
µs
µs
ns
µs
µs
ns
ns
ns
ns
pF
ns
µs
Note 1:
All parameters tested at T
A
= +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. I
SINK
≤ 6mA. t
R
and t
F
measured between 0.3 x V+ and 0.7 x V+.
Note 5:
Input filters on the SDA and SCL inputs suppress noise spikes less than 50ns.
www.maximintegrated.com
Maxim Integrated
│
3
MAX7321
I
2
C Port Expander with 8 Open-Drain I/Os
(T
A
= +25°C, unless otherwise noted.)
Typical Operating Characteristics
STANDBY CURRENT vs. TEMPERATURE
MAX7321 toc01
MAX7321 toc02
1.8
STANDBY CURRENT (µA)
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0
V+ = +2.5V
V+ = +3.3V
f
SCL
= 0kHz
f
SCL
= 400kHz
V+ = +5.0V
OUTPUT VOLTAGE LOW (V)
50
SUPPLY CURRENT (µA)
40
30
20
10
0
V+ = +1.71V
V+ = +3.3V
V+ = +2.5V
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0
V+ = +1.71V
I
SINK
= 5mA
V+ = +5.0V
I
SINK
= 20mA
V+ = +5.0V
V+ = +2.5V
V+ = +3.3V
I
SINK
= 10mA
I
SINK
= 15mA
V+ = +1.71V
-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)
-40 -25 -10 5 20 35 50 65 80 95 110 125
TEMPERATURE (
°
C)
Pin Description
PIN
QSOP
1, 3
2
4–7, 9–12
8
13
14
15
16
—
TQFN
15, 1
16
2–5, 7–10
6
11
12
13
14
EP
NAME
AD0,
AD2
RST
P0–P7
GND
INT
SCL
SDA
V+
EP
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 3).
Reset Input, Active Low. Drive
RST
low to clear the 2-wire interface.
Input/output Ports. P0 to P7 are open-drain I/Os.
Ground
Interrupt Output.
INT
is an open-drain output.
I
2
C-Compatible Serial-Clock Input
I
2
C-Compatible Serial-Data I/O
Positive Supply Voltage. Bypass V+ to GND with a ceramic capacitor of at least
0.047µF as close to the device as possible.
Exposed Pad. Connect exposed pad to GND.
www.maximintegrated.com
Maxim Integrated
│
4
MAX7321 toc03
2.0
60
SUPPLY CURRENT vs. TEMPERATURE
0.40
OUTPUT VOLTAGE LOW
vs. TEMPERATURE
MAX7321
I
2
C Port Expander with 8 Open-Drain I/Os
Detailed Description
MAX7319–MAX7329 Family Comparison
The MAX7319–MAX7323 family consists of five pin-
compatible, 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 pin-
compatible, 16-port expanders that integrate the
functions 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 +5.5V, independent
of the MAX7321’s supply voltage.
The MAX7321 is set to one of 16 I
2
C slave addresses
(0x60 to 0x6F) using the address select inputs AD0 and
AD2, and is accessed over an I
2
C serial interface up
to 400kHz. The
RST
input clears the serial interface in
Table 1. MAX7319–MAX7329 Family Comparison
PART
I
2
C
INPUT
SLAVE
INPUTS INTERRUPT
ADDRESS
MASK
OPEN-
DRAIN
OUTPUTS
PUSH-
PULL
OUTPUTS
APPLICATION
8-PORT EXPANDERS
Input-only versions:
8 input ports with programmable latching transition
detection interrupt and selectable pullups.
MAX7319
110xxxx
8
Yes
—
—
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 open-
rain outputs, and require no pullup resistors.
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
—
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.
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
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