19-2438; Rev 4; 5/04
4-Wire-Interfaced, 2.5V to 5.5V, 20-Port and
28-Port I/O Expander
General Description
The MAX7301 compact, serial-interfaced I/O expander
(or general-purpose I/O (GPIO) peripheral) provides
microprocessors with up to 28 ports. Each port is indi-
vidually user configurable to either a logic input or logic
output.
Each port can be configured either as a push-pull logic
output capable of sinking 10mA and sourcing 4.5mA,
or a Schmitt logic input with optional internal pullup.
Seven ports feature configurable transition detection
logic, which generates an interrupt upon change of port
logic level. The MAX7301 is controlled through an
SPI™-compatible 4-wire serial interface.
The MAX7301AAX and MAX7301AGL have 28 ports and
are available in 36-pin SSOP and 40-pin QFN packages,
respectively. The MAX7301AAI and MAX7301ANI have
20 ports and are available in 28-pin SSOP and 28-pin DIP
packages, respectively.
For a 2-wire interfaced version, refer to the MAX7300
data sheet.
For a pin-compatible port expander with additional
24mA constant-current LED drive capability, refer to the
MAX6957 data sheet.
Features
♦
High-Speed 26MHz SPI-/QSPI-™/MICROWIRE™-
Compatible Serial Interface
♦
2.5V to 5.5V Operation
♦
-40°C to +125°C Temperature Range
♦
20 or 28 I/O Ports, Each Configurable as
Push-Pull Logic Output
Schmitt Logic Input
Schmitt Logic Input with Internal Pullup
♦
11µA (max) Shutdown Current
♦
Logic Transition Detection for Seven I/O Ports
MAX7301
Ordering Information
PART
MAX7301ANI
MAX7301AAI
MAX7301AAX
MAX7301AGL
TEMP RANGE
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
-40°C to +125°C
PIN-PACKAGE
28 DIP
28 SSOP
36 SSOP
40 QFN
Applications
White Goods
Automotive
Gaming Machines
Industrial Controllers
System Monitoring
47nF
39kΩ
3V
36 V+
3 GND
2 GND
1
P4 32
P5 30
P6 28
P7 26
I/O 4
I/O 5
I/O 6
I/O 7
I/O 8
I/O 9
I/O 10
I/O 11
I/O 12
I/O 13
I/O 14
I/O 15
I/O 16
I/O 17
I/O 18
I/O 19
I/O 20
I/O 21
I/O 22
I/O 23
I/O 24
I/O 25
I/O 26
I/O 27
I/O 28
I/O 29
I/O 30
I/O 31
Typical Operating Circuit
MAX7301
ISET
CHIP SELECT
CLOCK IN
DATA IN
DATA OUT
35
CS
33
SCLK
34
DIN
4
DOUT
31 P31
29 P30
27 P29
25 P28
24 P27
23 P26
22 P25
21
P24
P8 5
P9 7
P10 9
P11 11
P12 6
P13 8
P14 10
P15 12
P16 13
P17 14
P18 15
P19 16
P20 17
P21 18
P22 19
P23 20
Pin Configurations appear at end of data sheet.
SPI and QSPI are trademarks of Motorola, Inc.
MICROWIRE is a trademark of National Semiconductor Corp.
________________________________________________________________
Maxim Integrated Products
1
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
4-Wire-Interfaced, 2.5V to 5.5V, 20-Port and
28-Port I/O Expander
MAX7301
ABSOLUTE MAXIMUM RATINGS
Voltage (with respect to GND)
V+ .............................................................................-0.3V to +6V
All Other pins................................................-0.3V to (V+ + 0.3V)
P4–P31 Current ................................................................±30mA
GND Current .....................................................................800mA
Continuous Power Dissipation (T
A
= +70°C)
28-Pin PDIP (derate 20.8mW/°C above +70°C).........1667mW
28-Pin SSOP (derate 9.5mW/°C above +70°C) ...........762mW
36-Pin SSOP (derate 11.8mW/°C above +70°C) .........941mW
40-Pin QFN (derate 23.25mW/°C above +70°C) .......1860mW
Operating Temperature Range
(T
MIN
, T
MAX
) ..................................................-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.
ELECTRICAL CHARACTERISTICS
(Typical Operating Circuit, V+ = 2.5V to 5.5V, T
A
= T
MIN
to T
MAX
, unless otherwise noted.) (Note 1)
PARAMETER
Operating Supply Voltage
Shutdown Supply Current
SYMBOL
V+
I
SHDN
All digital inputs at V+
or GND
All ports programmed
as outputs high, no
load, all other inputs
at V+ or GND
All ports programmed
as outputs low, no
load, all other inputs
at V+ or GND
All ports programmed
as inputs without
pullup, ports, and all
other inputs at V+ or
GND
T
A
= +25°C
T
A
= -40°C to +85°C
T
A
= T
MIN
to T
MAX
T
A
= +25°C
T
A
= -40°C to +85°C
T
A
= T
MIN
to T
MAX
T
A
= +25°C
T
A
= -40°C to +85°C
T
A
= T
MIN
to T
MAX
T
A
= +25°C
T
A
= -40°C to +85°C
T
A
= T
MIN
to T
MAX
110
170
180
Operating Supply Current
(Output High)
I
GPOH
CONDITIONS
MIN
2.5
5.5
TYP
MAX
5.5
8
10
11
230
250
270
210
230
240
135
140
145
µA
µA
µA
µA
UNITS
V
Operating Supply Current
(Output Low)
I
GPOL
Operating Supply Current
(Input)
I
GPI
INPUTS AND OUTPUTS
Logic High Input Voltage
Port Inputs
Logic Low Input Voltage
Port Inputs
Input Leakage Current
GPIO Input Internal Pullup to V+
Hysteresis Voltage GPIO Inputs
V
IH
V
IL
I
IH
, I
IL
I
PU
∆V
I
GPIO outputs, I
SOURCE
= 2mA,
T
A
= -40°C to +85°C
GPIO outputs, I
SOURCE
= 1mA,
T
A
= T
MIN
to T
MAX
(Note 2)
V+ -
0.7
V
V+ -
0.7
GPIO inputs without pullup,
VPORT = V+ to GND
V+ = 2.5V
V+ = 5.5V
-100
12
80
±1
19
120
0.3
0.7
✕
V+
0.3
✕
V+
+100
30
180
V
V
nA
µA
V
Output High Voltage
V
OH
2
_______________________________________________________________________________________
4-Wire-Interfaced, 2.5V to 5.5V, 20-Port and
28-Port I/O Expander
ELECTRICAL CHARACTERISTICS (continued)
(Typical Operating Circuit, V+ = 2.5V to 5.5V, T
A
= T
MIN
to T
MAX
, unless otherwise noted.) (Note 1)
PARAMETER
Port Sink Current
Output Short-Circuit Current
Input High-Voltage SCLK, DIN,
CS
Input Low-Voltage SCLK, DIN,
CS
Input Leakage Current SCLK,
DIN,
CS
Output High-Voltage DOUT
Output Low-Voltage DOUT
SYMBOL
I
OL
I
OLSC
V
IH
V
IL
I
IH
, I
IL
V
OH
V
OL
I
SOURCE
= 1.6mA
I
SINK
= 1.6mA
-50
V+ -
0.5
0.4
V
PORT
= 0.6V
Port configured output low, shorted to V+
V+
≤
3.3V
V+ > 3.3V
CONDITIONS
MIN
2
2.75
1.6
2
0.6
+50
TYP
10
11
MAX
18
20
UNITS
mA
mA
V
V
nA
V
V
MAX7301
TIMING CHARACTERISTICS (Figure 3)
(V+ = 2.5V to 5.5V, T
A
= T
MIN
to T
MAX
, unless otherwise noted.) (Note 1)
PARAMETER
CLK Clock Period
CLK Pulse Width High
CLK Pulse Width Low
CS
Fall to SCLK Rise Setup Time
CLK Rise to
CS
Rise Hold Time
DIN Setup Time
DIN Hold Time
Output Data Propagation Delay
Minimum
CS
Pulse High
SYMBOL
t
CP
t
CH
t
CL
t
CSS
t
CSH
t
DS
t
DH
t
DO
t
CSW
C
LOAD
= 25pF
19
CONDITIONS
MIN
38.4
19
19
9.5
0
9.5
0
21
TYP
MAX
UNITS
ns
ns
ns
ns
ns
ns
ns
ns
ns
Note 1:
All parameters tested at T
A
= +25°C. Specifications over temperature are guaranteed by design.
Note 2:
Guaranteed by design.
_______________________________________________________________________________________
3
4-Wire-Interfaced, 2.5V to 5.5V, 20-Port and
28-Port I/O Expander
MAX7301
__________________________________________Typical Operating Characteristics
(T
A
= +25°C, unless otherwise noted.)
OPERATING SUPPLY CURRENT
vs. TEMPERATURE
MAX7301 toc01
SHUTDOWN SUPPLY CURRENT
vs. TEMPERATURE
MAX7301 toc02
OPERATING SUPPLY CURRENT
vs. V+ (OUTPUTS UNLOADED)
MAX7301 toc03
0.40
0.36
0.32
SUPPLY CURRENT (mA)
0.28
0.24
0.20
0.16
0.12
0.08
0.04
0
-40.0
-12.5
15.0
42.5
70.0
97.5
ALL PORTS INPUT HIGH
ALL PORTS
OUTPUT (1)
ALL PORTS
OUTPUT (0)
V+ = 2.5V TO 5.5V
NO LOAD
8
1
V+ = 5.5V
6
SUPPLY CURRRENT (mA)
7
SUPPLY CURRENT (µA)
ALL PORTS OUTPUT (1)
ALL PORTS OUTPUT (0)
5
V+ = 3.3V
4
V+ = 2.5V
ALL PORTS INPUT
(PULLUPS DISABLED)
0.1
-40.0
-12.5
15.0
42.5
70.0
97.5
125.0
2.0
2.5
3.0
3.5
4.0
4.5
5.0
5.5
TEMPERATURE (°C)
V+ (V)
3
125.0
TEMPERATURE (°C)
GPO SINK CURRENT vs. TEMPERATURE
(OUTPUT = 0)
MAX7301 toc04
GPO SOURCE CURRENT vs. TEMPERATURE
(OUTPUT = 1)
V
PORT
= 1.4
8
PORT SOURCE CURRENT (mA)
7
6
5
4
3
2
V+ = 5.5V
V+ = 3.3V
V+ = 2.5V
MAX7301 toc05
18
V+ = 2.5V TO 5.5V, V
PORT
= 0.6V
16
PORT SINK CURRENT (mA)
14
12
10
8
6
4
2
-40.0
-12.5
15.0
42.5
70.0
97.5
9
125.0
-40.0
-12.5
15.0
42.5
70.0
97.5
125.0
TEMPERATURE (°C)
TEMPERATURE (°C)
GPI PULLUP CURRENT
vs. TEMPERATURE
MAX7301 toc06
GPO SHORT-CIRCUIT CURRENT
vs. TEMPERATURE
MAX7301 toc07
1000
100
PULLUP CURRENT (µA)
PORT CURRENT (mA)
V+ = 5.5V
GPO = 0, PORT
SHORTED TO V+
10
100
V+ = 3.3V
V+ = 2.5V
GPO = 1, PORT
SHORTED TO GND
10
-40.0
-12.5
15.0
42.5
70.0
97.5
125.0
TEMPERATURE (°C)
1
-40.0
-12.5
15.0
42.5
70.0
97.5
125.0
TEMPERATURE (°C)
4
_______________________________________________________________________________________
4-Wire-Interfaced, 2.5V to 5.5V, 20-Port and
28-Port I/O Expander
Pin Description
PIN
SSOP
1
2, 3
4
—
SSOP
DIP
1
2, 3
4
5–24
NAME
QFN
36
37, 38, 39
40
—
1–10,
12–19,
21–30
32
33
34
35
PAD
ISET
GND
DOUT
P12–P31
Bias Current Setting. Connect I
SET
to GND through a resistor (R
ISET
) value of
39kΩ to 120kΩ.
Ground
4-Wire Interface Serial Data Output Port
I/O Ports. P12 to P31 can be configured as push-pull outputs, CMOS logic
inputs, or CMOS logic inputs with weak pullup resistor.
I/O Ports. P4 to P31 can be configured as push-pull outputs, CMOS logic
inputs, or CMOS logic inputs with weak pullup resistor.
4-Wire Interface Serial Clock Input Port
4-Wire Interface Serial Data Input Port
4-Wire Interface Chip-Select Input, Active Low
Positive Supply Voltage. Bypass V+ to GND with a minimum 0.047µF capacitor.
Exposed Pad on Package Underside. Connect to GND.
FUNCTION
MAX7301
5–32
—
P4–P31
33
34
35
36
—
25
26
27
28
—
SCLK
DIN
CS
V+
Exposed
Pad
Detailed Description
The MAX7301 GPIO peripheral provides up to 28 I/O
ports, P4 to P31, controlled through an SPI-compatible
serial interface. The ports can be configured to any
combination of logic inputs and logic outputs, and
default to logic inputs on power-up.
Figure 1 is the MAX7301 functional diagram. Any I/O
port can be configured as a push-pull output (sinking
10mA, sourcing 4.5mA), or a Schmitt-trigger logic
input. Each input has an individually selectable internal
pullup resistor. Additionally, transition detection allows
seven ports (P24 through P30) to be monitored in any
maskable combination for changes in their logic status.
A detected transition is flagged through an interrupt pin
(port P31).
The port configuration registers set the 28 ports, P4 to
P31, individually as GPIO. A pair of bits in registers
0x09 through 0x0F sets each port’s configuration
(Tables 1 and 2).
The 36-pin MAX7301AAX has 28 ports, P4 to P31. The
28-pin MAX7301ANI and MAX7301AAI make only 20
ports available—P12 to P31. The eight unused ports
should be configured as outputs on power-up by writ-
ing 0x55 to registers 0x09 and 0x0A. If this is not done,
the eight unused ports remain as floating inputs and
quiescent supply current rises, although there is no
damage to the part.
Register Control of I/O Ports
Across Multiple Drivers
The MAX7301 offers 20 or 28 I/O ports, depending on
package choice.
Two addressing methods are available. Any single port
(bit) can be written (set/cleared) at once; or, any
sequence of eight ports can be written (set/cleared) in
any combination at once. There are no boundaries; it is
equally acceptable to write P0 through P7, P1 through
P8, or P31 through P38 (P32 through P38 are nonexis-
tent, so the instructions to these bits are ignored).
Shutdown
When the MAX7301 is in shutdown mode, all ports are
forced to inputs (which can be read), and the pullup
current sources are turned off. Data in the port and
control registers remain unaltered so port configuration
and output levels are restored when the MAX7301 is
taken out of shutdown. The display driver can still be
programmed while in shutdown mode. For minimum
supply current in shutdown mode, logic inputs should
be at GND or V+ potential. Shutdown mode is exited by
setting the S bit in the configuration register (Table 6).
5
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