19-2438; Rev 4; 5/04
4-Wire-Interfaced, 2.5V to 5.5V, 20-Port and
28-Port I/O Expander
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 individually 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.
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
Ordering Information
PART
TEMP RANGE
PIN-PACKAGE
For a 2-wire interfaced version, refer to the MAX7300
data sheet.
MAX7301ANI
-40°C to +125°C
28 DIP
MAX7301AAI
-40°C to +125°C
28 SSOP
For a pin-compatible port expander with additional
24mA constant-current LED drive capability, refer to the
MAX6957 data sheet.
MAX7301AAX
-40°C to +125°C
36 SSOP
MAX7301AGL
-40°C to +125°C
40 QFN
Applications
White Goods
Typical Operating Circuit
Automotive
Gaming Machines
3V
System Monitoring
47nF
3 GND
2 GND
39kΩ
CHIP SELECT
CLOCK IN
DATA IN
DATA OUT
Pin Configurations appear at end of data sheet.
SPI and QSPI are trademarks of Motorola, Inc.
P4 32
P5 30
P6 28
P7 26
36 V+
Industrial Controllers
1
MAX7301
ISET
35
CS
33
SCLK
34
DIN
4
DOUT
P8 5
P9 7
P10 9
P11 11
P12 6
P13 8
P14 10
P15 12
31 P31
29 P30
27 P29
25 P28
24 P27
P16 13
P17 14
P18 15
P19 16
P20 17
23 P26
22 P25
21
P24
P21 18
P22 19
P23 20
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
MICROWIRE is a trademark of National Semiconductor Corp.
________________________________________________________________ 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
MAX7301
General Description
MAX7301
4-Wire-Interfaced, 2.5V to 5.5V, 20-Port and
28-Port I/O Expander
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 (TA = +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
(TMIN, TMAX) ..................................................-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, TA = TMIN to TMAX, unless otherwise noted.) (Note 1)
PARAMETER
SYMBOL
Operating Supply Voltage
V+
Shutdown Supply Current
ISHDN
Operating Supply Current
(Output High)
Operating Supply Current
(Output Low)
Operating Supply Current
(Input)
IGPOH
IGPOL
IGPI
CONDITIONS
MIN
TYP
2.5
All digital inputs at V+
or GND
TA = +25°C
5.5
MAX
UNITS
5.5
V
8
TA = -40°C to +85°C
10
TA = TMIN to TMAX
11
All ports programmed
as outputs high, no
load, all other inputs
at V+ or GND
TA = +25°C
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
TA = +25°C
180
TA = -40°C to +85°C
230
250
TA = TMIN to TMAX
µA
µA
270
170
210
TA = -40°C to +85°C
230
TA = TMIN to TMAX
240
TA = +25°C
110
µA
135
TA = -40°C to +85°C
140
TA = TMIN to TMAX
145
µA
INPUTS AND OUTPUTS
Logic High Input Voltage
Port Inputs
VIH
Logic Low Input Voltage
Port Inputs
VIL
Input Leakage Current
GPIO Input Internal Pullup to V+
IPU
Hysteresis Voltage GPIO Inputs
∆VI
Output High Voltage
2
IIH, IIL
VOH
0.7 ✕
V+
GPIO inputs without pullup,
VPORT = V+ to GND
-100
V
±1
0.3 ✕
V+
V
+100
nA
V+ = 2.5V
12
19
30
V+ = 5.5V
80
120
180
0.3
GPIO outputs, ISOURCE = 2mA,
TA = -40°C to +85°C
V+ 0.7
GPIO outputs, ISOURCE = 1mA,
TA = TMIN to TMAX (Note 2)
V+ 0.7
µA
V
V
_______________________________________________________________________________________
4-Wire-Interfaced, 2.5V to 5.5V, 20-Port and
28-Port I/O Expander
(Typical Operating Circuit, V+ = 2.5V to 5.5V, TA = TMIN to TMAX, unless otherwise noted.) (Note 1)
PARAMETER
Port Sink Current
SYMBOL
IOL
Output Short-Circuit Current
IOLSC
Input High-Voltage SCLK, DIN,
CS
VIH
Input Low-Voltage SCLK, DIN,
CS
VIL
Input Leakage Current SCLK,
DIN, CS
IIH, IIL
CONDITIONS
MIN
TYP
MAX
2
10
18
mA
Port configured output low, shorted to V+
2.75
11
20
mA
V+ ≤ 3.3V
1.6
V+ > 3.3V
2
VPORT = 0.6V
V
-50
Output High-Voltage DOUT
VOH
ISOURCE = 1.6mA
Output Low-Voltage DOUT
VOL
ISINK = 1.6mA
UNITS
0.6
V
+50
nA
V+ 0.5
V
0.4
V
MAX
UNITS
TIMING CHARACTERISTICS (Figure 3)
(V+ = 2.5V to 5.5V, TA = TMIN to TMAX, unless otherwise noted.) (Note 1)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
CLK Clock Period
tCP
38.4
ns
CLK Pulse Width High
tCH
19
ns
CLK Pulse Width Low
tCL
19
ns
CS Fall to SCLK Rise Setup Time
tCSS
9.5
ns
CLK Rise to CS Rise Hold Time
ns
tCSH
0
DIN Setup Time
tDS
9.5
ns
DIN Hold Time
tDH
0
ns
Output Data Propagation Delay
Minimum CS Pulse High
tDO
tCSW
CLOAD = 25pF
21
19
ns
ns
Note 1: All parameters tested at TA = +25°C. Specifications over temperature are guaranteed by design.
Note 2: Guaranteed by design.
_______________________________________________________________________________________
3
MAX7301
ELECTRICAL CHARACTERISTICS (continued)
__________________________________________Typical Operating Characteristics
(TA = +25°C, unless otherwise noted.)
OPERATING SUPPLY CURRENT
vs. TEMPERATURE
ALL PORTS
OUTPUT (0)
ALL PORTS
OUTPUT (1)
0.24
0.20
0.16
0.12
0.08
1
V+ = 5.5V
6
5
MAX7301 toc03
7
SUPPLY CURRENT (µA)
0.32
0.28
8
SUPPLY CURRRENT (mA)
V+ = 2.5V TO 5.5V
NO LOAD
MAX7301 toc02
V+ = 2.5V
V+ = 3.3V
ALL PORTS OUTPUT (1)
ALL PORTS OUTPUT (0)
4
ALL PORTS INPUT
(PULLUPS DISABLED)
ALL PORTS INPUT HIGH
0.04
0
0.1
3
-40.0
-12.5
15.0
42.5
70.0
97.5
125.0
-40.0
-12.5
TEMPERATURE (°C)
15.0
42.5
70.0
3.0
3.5
16
14
12
10
8
6
9
VPORT = 1.4
8
PORT SOURCE CURRENT (mA)
V+ = 2.5V TO 5.5V, VPORT = 0.6V
4.0
V+ (V)
GPO SOURCE CURRENT vs. TEMPERATURE
(OUTPUT = 1)
MAX7301 toc04
18
V+ = 5.5V
7
V+ = 3.3V
6
V+ = 2.5V
5
4
3
4
2
2
-40.0
-12.5
15.0
42.5
70.0
97.5
125.0
-40.0
-12.5
15.0
42.5
70.0
97.5
TEMPERATURE (°C)
TEMPERATURE (°C)
GPI PULLUP CURRENT
vs. TEMPERATURE
GPO SHORT-CIRCUIT CURRENT
vs. TEMPERATURE
100
MAX7301 toc06
1000
PORT CURRENT (mA)
V+ = 5.5V
100
V+ = 3.3V
V+ = 2.5V
125.0
MAX7301 toc07
PORT SINK CURRENT (mA)
2.5
TEMPERATURE (°C)
GPO SINK CURRENT vs. TEMPERATURE
(OUTPUT = 0)
PULLUP CURRENT (µA)
2.0
125.0
97.5
MAX7301 toc05
0.36
OPERATING SUPPLY CURRENT
vs. V+ (OUTPUTS UNLOADED)
SHUTDOWN SUPPLY CURRENT
vs. TEMPERATURE
MAX7301 toc01
0.40
SUPPLY CURRENT (mA)
MAX7301
4-Wire-Interfaced, 2.5V to 5.5V, 20-Port and
28-Port I/O Expander
GPO = 0, PORT
SHORTED TO V+
10
GPO = 1, PORT
SHORTED TO GND
10
1
-40.0
-12.5
15.0
42.5
70.0
TEMPERATURE (°C)
4
97.5
125.0
-40.0
-12.5
15.0
42.5
70.0
97.5
TEMPERATURE (°C)
_______________________________________________________________________________________
125.0
4.5
5.0
5.5
4-Wire-Interfaced, 2.5V to 5.5V, 20-Port and
28-Port I/O Expander
PIN
NAME
SSOP
SSOP
DIP
QFN
1
1
36
2, 3
2, 3
4
4
—
FUNCTION
ISET
Bias Current Setting. Connect ISET to GND through a resistor (RISET) value of
39kΩ to 120kΩ.
37, 38, 39
GND
Ground
40
DOUT
4-Wire Interface Serial Data Output Port
5–24
—
P12–P31
I/O Ports. P12 to P31 can be configured as push-pull outputs, CMOS logic
inputs, or CMOS logic inputs with weak pullup resistor.
5–32
—
1–10,
12–19,
21–30
P4–P31
I/O Ports. P4 to P31 can be configured as push-pull outputs, CMOS logic
inputs, or CMOS logic inputs with weak pullup resistor.
33
25
32
SCLK
4-Wire Interface Serial Clock Input Port
34
26
33
DIN
4-Wire Interface Serial Data Input Port
35
27
34
CS
4-Wire Interface Chip-Select Input, Active Low
36
28
35
V+
Positive Supply Voltage. Bypass V+ to GND with a minimum 0.047µF capacitor.
—
—
PAD
Exposed
Pad
Exposed Pad on Package Underside. Connect to GND.
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 writing 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 nonexistent, 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
MAX7301
Pin Description
MAX7301
4-Wire-Interfaced, 2.5V to 5.5V, 20-Port and
28-Port I/O Expander
Table 1. Port Configuration Map
ADDRESS
CODE (HEX)
REGISTER
Port Configuration for P7, P6, P5, P4
REGISTER DATA
D7
0x09
D6
D5
P7
D4
D3
P6
D2
P5
D1
D0
P4
Port Configuration for P11, P10, P9, P8
0x0A
P11
P10
P9
P8
Port Configuration for P15, P14, P13, P12
0x0B
P15
P14
P13
P12
Port Configuration for P19, P18, P17, P16
0x0C
P19
P18
P17
P16
Port Configuration for P23, P22, P21, P20
0x0D
P23
P22
P21
P20
Port Configuration for P27, P26, P25, P24
0x0E
P27
P26
P25
P24
Port Configuration for P31, P30, P29, P28
0x0F
P31
P30
P29
P28
Table 2. Port Configuration Matrix
MODE
PORT
REGISTER
(0x20–0x5F)
(0xA0–0xDF)
FUNCTION
ADDRESS
CODE (HEX)
PIN BEHAVIOR
DO NOT USE THIS SETTING
Output
GPIO Output
Input
GPIO Input
Without Pullup
Input
GPIO Input with Pullup
UPPER
LOWER
0x09 to 0x0F
0
0
0x09 to 0x0F
0
1
Register bit = 0
Active-low logic output
Register bit = 1
Active-high logic output
Register bit =
input logic level
Schmitt logic input
0x09 to 0x0F
1
0
Schmitt logic input with pullup
0x09 to 0x0F
1
1
Serial Interface
The MAX7301 communicates through an SPI-compatible 4-wire serial interface. The interface has three
inputs, Clock (SCLK), Chip Select (CS), and Data In
(DIN), and one output, Data Out (DOUT). CS must be
low to clock data into or out of the device, and DIN
must be stable when sampled on the rising edge of
SCLK. DOUT provides a copy of the bit that was input
15.5 clocks earlier, or upon a query it outputs internal
register data, and is stable on the rising edge of SCLK.
Note that the SPI protocol expects DOUT to be high
impedance when the MAX7301 is not being
accessed; DOUT on the MAX7301 is never high
impedance. See www.maxim-ic.com/an 1879 for
ways to convert DOUT to tri-state, if required.
SCLK and DIN may be used to transmit data to other
peripherals, so the MAX7301 ignores all activity on
SCLK and DIN except between the fall and subsequent
rise of CS.
Control and Operation Using the
4-Wire Interface
Controlling the MAX7301 requires sending a 16-bit
word. The first byte, D15 through D8, is the command
6
PORT
CONFIGURATION
BIT PAIR
address (Table 3), and the second byte, D7 through
D0, is the data byte (Table 4 through Table 8).
Connecting Multiple MAX7301s
to the 4-Wire Bus
Multiple MAX7301s may be daisy-chained by connecting the DOUT of one device to the DIN of the next, and
driving SCLK and CS lines in parallel (Figure 3). Data at
DIN propagates through the internal shift registers and
appears at DOUT 15.5 clock cycles later, clocked out
on the falling edge of SCLK. When sending commands
to multiple MAX7301s, all devices are accessed at the
same time. An access requires (16 ✕ n) clock cycles,
where n is the number of MAX7301s connected together. To update just one device in a daisy-chain, the user
can send the No-Op command (0x00) to the others.
Writing Device Registers
The MAX7301 contains a 16-bit shift register into which
DIN data are clocked on the rising edge of SCLK, when
CS is low. When CS is high, transitions on SCLK have
no effect. When CS goes high, the 16 bits in the Shift
register are parallel loaded into a 16-bit latch. The 16
bits in the latch are then decoded and executed.
_______________________________________________________________________________________
4-Wire-Interfaced, 2.5V to 5.5V, 20-Port and
28-Port I/O Expander
MAX7301
PORT REGISTERS
CONFIGURATION
MASK REGISTER
CONFIGURATION
REGISTERS
PORT CHANGE
DETECTOR
GPIO
P4 TO P31
DATA
R/W
CE
8
R/W
GPIO DATA
8
COMMAND
REGISTER DECODE
8
8
DATA BYTE
COMMAND BYTE
CS
D0
D1
D2
D3
D4
D5
D6
D7
D8
D9
D10
D11
D12
D13
D14
D15
DIN
D0
D1
D2
D3
D4
D5
D6
D7
D8
D9
D10
D11
D12
D13
D14
D15
DOUT
SCLK
Figure 1. MAX7301 Functional Diagram
The MAX7301 is written to using the following
sequence:
1) Take SCLK low.
2) Take CS low. This enables the internal 16-bit shift
register.
3) Clock 16 bits of data into DIN—D15 first, D0 last—
observing the setup and hold times (bit D15 is low,
indicating a write command).
4) Take CS high (either while SCLK is still high after
clocking in the last data bit, or after taking SCLK
low).
5) Take SCLK low (if not already low).
Figure 4 shows a write operation when 16 bits are
transmitted.
It is acceptable to clock more than 16 bits into the
MAX7301 between taking CS low and taking CS high
again. In this case, only the last 16 bits clocked into the
MAX7301 are retained.
Reading Device Registers
Any register data within the MAX7301 may be read by
sending a logic high to bit D15. The sequence is:
1) Take SCLK low.
2) Take CS low (this enables the internal 16-bit Shift
register).
3) Clock 16 bits of data into DIN—D15 first to D0 last.
D15 is high, indicating a read command and bits
D14 through D8 containing the address of the register to be read. Bits D7–D0 contain dummy data,
which is discarded.
4) Take CS high (either while SCLK is still high after
clocking in the last data bit, or after taking SCLK
low), positions D7 through D0 in the Shift register
are now loaded with the register data addressed by
bits D1 through D8.
5) Take SCLK low (if not already low).
6) Issue another read or write command (which can
be a No-Op), and examine the bit stream at DOUT;
the second 8 bits are the contents of the register
addressed by bits D1 through D8 in step 3.
_______________________________________________________________________________________
7
MAX7301
4-Wire-Interfaced, 2.5V to 5.5V, 20-Port and
28-Port I/O Expander
CS
tCSS
tCH
tCSH
tCSH
tCL
SCLK
tDS
tDH
DIN
tDO
DOUT
Figure 2. 4-Wire Interface
Initial Power-Up
On initial power-up, all control registers are reset, and
the MAX7301 enters shutdown mode (Table 4).
Transition (Port Data Change) Detection
Port transition detection allows any combination of the
seven ports P24–P30 to be continuously monitored for
changes in their logic status (Figure 5). A detected
change is flagged on port P31, which is used as an
active-high interrupt output (INT). Note that the
MAX7301 does not identify which specific port(s)
caused the interrupt, but provides an alert that one or
more port levels have changed.
The mask register contains 7 mask bits that select
which of the seven ports, P24–P30 are to be monitored
(Table 8). Set the appropriate mask bit to enable that
port for transition detect. Clear the mask bit if transitions
on that port are to be ignored. Transition detection
works regardless of whether the port being monitored is
set to input or output, but generally it is not particularly
useful to enable transition detection for outputs.
Port P31 must be configured as an output in order to
work as the interrupt output INT when transition detection is used. Port P31 is set as output by writing bit D7
= 0 and bit D6 = 1 to the port configuration register
(Table 1).
To use transition detection, first set up the mask register and configure port P31 as an output, as described
above. Then enable transition detection by setting the
M bit in the configuration register (Table 7). Whenever
8
the configuration register is written with the M bit set,
the MAX7301 updates an internal 7-bit snapshot register, which holds the comparison copy of the logic states
of ports P24 through P30. The update action occurs
regardless of the previous state of the M bit, so that it is
not necessary to clear the M bit and then set it again to
update the snapshot register.
When the configuration register is written with the M bit
set, transition detection is enabled and remains
enabled until either the configuration register is written
with the M bit clear, or a transition is detected. The INT
output port P31 goes low, if it was not already low.
Once transition detection is enabled, the MAX7301
continuously compares the snapshot register against
the changing states of P24 through P31. If a change on
any of the monitored ports is detected, even for a short
time (like a pulse), INT output port P31 is latched high.
The INT output is not cleared if more changes occur or
if the data pattern returns to its original snapshot condition. The only way to clear INT is to access (read or
write) the transition detection mask register (Table 8).
Transition detection is a one-shot event. When INT has
been cleared after responding to a transition event,
transition detection is automatically disabled, even
though the M bit in the configuration register remains
set (unless cleared by the user). Reenable transition
detection by writing the configuration register with the
M bit set, to take a new snapshot of the seven ports
P24 to P30.
_______________________________________________________________________________________
4-Wire-Interfaced, 2.5V to 5.5V, 20-Port and
28-Port I/O Expander
MAX7301
MICROCONTROLLER
SERIAL DATA INPUT
SERIAL CS OUTPUT
SERIAL CLOCK OUTPUT
CS
CS
SCLK MAX7301
SCLK
DIN
SERIAL DATA OUTPUT
DOUT
CS
MAX7301
SCLK
DIN
DOUT
DIN
MAX7301
DOUT
Figure 3. Daisy-Chain Arrangement for Controlling Multiple MAX7301s
CS
SCLK
DIN
D15
=0
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
DOUT
D1
D0
D15 = 0
.
Figure 4. Transmission of a16-Bit Write to the MAX7301
External Component RISET
The MAX7301 uses an external resistor, RISET, to set
internal biasing. Use a resistor value of 39kΩ.
Applications Information
Low-Voltage Operation
The MAX7301 operates down to 2V supply voltage
(although the sourcing and sinking currents are not
guaranteed), providing that the MAX7301 is powered
up initially to at least 2.5V to trigger the device’s internal
reset, and also that the serial interface is constrained to
10Mbps.
SPI Routing Considerations
The MAX7301’s SPI interface is guaranteed to operate
at 26Mbps on a 2.5V supply, and on a 5V supply typically operates at 50Mbps. This means that transmission
line issues should be considered when the interface
connections are longer than 100mm, particularly with
higher supply voltages. Ringing manifests itself as
communication issues, often intermittent, typically due
to double clocking due to ringing at the SCLK input. Fit
a 1kΩ to 10kΩ parallel termination resistor to either
GND or V+ at the DIN, SCLK, and CS input to damp
ringing for moderately long interface runs. Use lineimpedance matching terminations when making connections between boards.
PC Board Layout Considerations
For the QFN version, connect the underside exposed
pad to GND. Ensure that all the MAX7301 GND connections are used. A ground plane is not necessary, but
may be useful to reduce supply impedance if the
MAX7301 outputs are to be heavily loaded. Keep the
track length from the ISET pin to the RISET resistor as
short as possible, and take the GND end of the resistor
either to the ground plane or directly to the ground pins.
Power-Supply Considerations
The MAX7301 operates with power-supply voltages of
2.5V to 5.5V. Bypass the power supply to GND with a
0.047µF capacitor as close to the device as possible.
Add a 1µF capacitor if the MAX7301 is far away from
the board’s input bulk decoupling capacitor.
Chip Information
TRANSISTOR COUNT: 30,316
PROCESS: CMOS
_______________________________________________________________________________________
9
MAX7301
4-Wire-Interfaced, 2.5V to 5.5V, 20-Port and
28-Port I/O Expander
Table 3. Register Address Map
COMMAND ADDRESS
D15
D14
D13
D12
D11
D10
D9
D8
HEX
CODE
No-Op
R/W
0
0
0
0
0
0
0
0x00
Configuration
R/W
0
0
0
0
1
0
0
0x04
Transition Detect Mask
R/W
0
0
0
0
1
1
0
0x06
Factory Reserved. Do not write to this.
R/W
0
0
0
0
1
1
1
0x07
Port Configuration P7, P6, P5, P4
R/W
0
0
0
1
0
0
1
0x09
Port Configuration P11, P10, P9, P8
R/W
0
0
0
1
0
1
0
0x0A
Port Configuration P15, P14, P13, P12
R/W
0
0
0
1
0
1
1
0x0B
Port Configuration P19, P18, P17, P16
R/W
0
0
0
1
1
0
0
0x0C
Port Configuration P23, P22, P21, P20
R/W
0
0
0
1
1
0
1
0x0D
Port Configuration P27, P26, P25, P24
R/W
0
0
0
1
1
1
0
0x0E
Port Configuration P31, P30, P29, P28
R/W
0
0
0
1
1
1
1
0x0F
Port 0 only (virtual port, no action)
R/W
0
1
0
0
0
0
0
0x20
Port 1 only (virtual port, no action)
R/W
0
1
0
0
0
0
1
0x21
Port 2 only (virtual port, no action)
R/W
0
1
0
0
0
1
0
0x22
Port 3 only (virtual port, no action)
R/W
0
1
0
0
0
1
1
0x23
Port 4 only (data bit D0. D7–D1 read as 0)
R/W
0
1
0
0
1
0
0
0x24
Port 5 only (data bit D0. D7–D1 read as 0)
R/W
0
1
0
0
1
0
1
0x25
Port 6 only (data bit D0. D7–D1 read as 0)
R/W
0
1
0
0
1
1
0
0x26
Port 7 only (data bit D0. D7–D1 read as 0)
R/W
0
1
0
0
1
1
1
0x27
Port 8 only (data bit D0. D7–D1 read as 0)
R/W
0
1
0
1
0
0
0
0x28
Port 9 only (data bit D0. D7–D1 read as 0)
R/W
0
1
0
1
0
0
1
0x29
Port 10 only (data bit D0. D7–D1 read as 0)
R/W
0
1
0
1
0
1
0
0x2A
Port 11 only (data bit D0. D7–D1 read as 0)
R/W
0
1
0
1
0
1
1
0x2B
Port 12 only (data bit D0. D7–D1 read as 0)
R/W
0
1
0
1
1
0
0
0x2C
Port 13 only (data bit D0. D7–D1 read as 0)
R/W
0
1
0
1
1
0
1
0x2D
Port 14 only (data bit D0. D7–D1 read as 0)
R/W
0
1
0
1
1
1
0
0x2E
Port 15 only (data bit D0. D7–D1 read as 0)
R/W
0
1
0
1
1
1
1
0x2F
Port 16 only (data bit D0. D7–D1 read as 0)
R/W
0
1
1
0
0
0
0
0x30
Port 17 only (data bit D0. D7–D1 read as 0)
R/W
0
1
1
0
0
0
1
0x31
Port 18 only (data bit D0. D7–D1 read as 0)
R/W
0
1
1
0
0
1
0
0x32
Port 19 only (data bit D0. D7–D1 read as 0)
R/W
0
1
1
0
0
1
1
0x33
Port 20 only (data bit D0. D7–D1 read as 0)
R/W
0
1
1
0
1
0
0
0x34
Port 21 only (data bit D0. D7–D1 read as 0)
R/W
0
1
1
0
1
0
1
0x35
Port 22 only (data bit D0. D7–D1 read as 0)
R/W
0
1
1
0
1
1
0
0x36
Port 23 only (data bit D0. D7–D1 read as 0)
R/W
0
1
1
0
1
1
1
0x37
Port 24 only (data bit D0. D7–D1 read as 0)
R/W
0
1
1
1
0
0
0
0x38
Port 25 only (data bit D0. D7–D1 read as 0)
R/W
0
1
1
1
0
0
1
0x39
REGISTER
10
______________________________________________________________________________________
4-Wire-Interfaced, 2.5V to 5.5V, 20-Port and
28-Port I/O Expander
COMMAND ADDRESS
D15
D14
D13
D12
D11
D10
D9
D8
HEX
CODE
Port 26 only (data bit D0. D7–D1 read as 0)
R/W
0
1
1
1
0
1
0
0x3A
Port 27 only (data bit D0. D7–D1 read as 0)
R/W
0
1
1
1
0
1
1
0x3B
Port 28 only (data bit D0. D7–D1 read as 0)
R/W
0
1
1
1
1
0
0
0x3C
Port 29 only (data bit D0. D7–D1 read as 0)
R/W
0
1
1
1
1
0
1
0x3D
Port 30 only (data bit D0. D7–D1 read as 0)
R/W
0
1
1
1
1
1
0
0x3E
Port 31 only (data bit D0. D7–D1 read as 0)
R/W
0
1
1
1
1
1
1
0x3F
4 ports 4–7 (data bits D0–D3. D4–D7 read as 0)
R/W
1
0
0
0
0
0
0
0x40
5 ports 4–8 (data bits D0–D4. D5–D7 read as 0)
R/W
1
0
0
0
0
0
1
0x41
6 ports 4–9 (data bits D0–D5. D6–D7 read as 0)
R/W
1
0
0
0
0
1
0
0x42
7 ports 4–10 (data bits D0–D6. D7 reads as 0)
R/W
1
0
0
0
0
1
1
0x43
8 ports 4–11 (data bits D0–D7)
R/W
1
0
0
0
1
0
0
0x44
8 ports 5–12 (data bits D0–D7)
R/W
1
0
0
0
1
0
1
0x45
8 ports 6–13 (data bits D0–D7)
R/W
1
0
0
0
1
1
0
0x46
8 ports 7–14 (data bits D0–D7)
R/W
1
0
0
0
1
1
1
0x47
8 ports 8–15 (data bits D0–D7)
R/W
1
0
0
1
0
0
0
0x48
8 ports 9–16 (data bits D0–D7)
R/W
1
0
0
1
0
0
1
0x49
8 ports 10–17 (data bits D0–D7)
R/W
1
0
0
1
0
1
0
0x4A
8 ports 11–18 (data bits D0–D7)
R/W
1
0
0
1
0
1
1
0x4B
8 ports 12–19 (data bits D0–D7)
R/W
1
0
0
1
1
0
0
0x4C
8 ports 13–20 (data bits D0–D7)
R/W
1
0
0
1
1
0
1
0x4D
8 ports 14–21 (data bits D0–D7)
R/W
1
0
0
1
1
1
0
0x4E
8 ports 15–22 (data bits D0–D7)
R/W
1
0
0
1
1
1
1
0x4F
8 ports 16–23 (data bits D0–D7)
R/W
1
0
1
0
0
0
0
0x50
8 ports 17–24 (data bits D0–D7)
R/W
1
0
1
0
0
0
1
0x51
8 ports 18–25 (data bits D0–D7)
R/W
1
0
1
0
0
1
0
0x52
8 ports 19–26 (data bits D0–D7)
R/W
1
0
1
0
0
1
1
0x53
8 ports 20–27 (data bits D0–D7)
R/W
1
0
1
0
1
0
0
0x54
8 ports 21–28 (data bits D0–D7)
R/W
1
0
1
0
1
0
1
0x55
8 ports 22–29 (data bits D0–D7)
R/W
1
0
1
0
1
1
0
0x56
8 ports 23–30 (data bits D0–D7)
R/W
1
0
1
0
1
1
1
0x57
8 ports 24–31 (data bits D0–D7)
R/W
1
0
1
1
0
0
0
0x58
7 ports 25–31 (data bits D0–D6. D7 reads as 0)
R/W
1
0
1
1
0
0
1
0x59
6 ports 26–31 (data bits D0–D5. D6–D7 read as 0)
R/W
1
0
1
1
0
1
0
0x5A
5 ports 27–31 (data bits D0–D4. D5–D7 read as 0)
R/W
1
0
1
1
0
1
1
0x5B
4 ports 28–31 (data bits D0–D3. D4–D7 read as 0)
R/W
1
0
1
1
1
0
0
0x5C
3 ports 29–31 (data bits D0–D2. D3–D7 read as 0)
R/W
1
0
1
1
1
0
1
0x5D
2 ports 30–31 (data bits D0–D1. D2–D7 read as 0)
R/W
1
0
1
1
1
1
0
0x5E
1 port 31 only (data bit D0. D1–D7 read as 0)
R/W
1
0
1
1
1
1
1
0x5F
REGISTER
Note: Unused bits read as 0.
______________________________________________________________________________________
11
MAX7301
Table 3. Register Address Map (continued)
MAX7301
4-Wire-Interfaced, 2.5V to 5.5V, 20-Port and
28-Port I/O Expander
GPIO INPUT
CONDITIONING
GPIO IN
GPIO/PORT
OUTPUT LATCH
GPIO/PORT OUT
P31
INT
OUTPUT LATCH
CLOCK PULSE AFTER EACH READ ACCESS TO MASK REGISTER
R
S
CONFIGURATION REGISTER M BIT = SET
GPIO INPUT
CONDITIONING
P30
GPIO IN
D
Q
GPIO/PORT OUT
MASK REGISTER BIT 6
GPIO/PORT OUTPUT LATCH
GPIO INPUT
CONDITIONING
P29
GPIO IN
D
Q
GPIO/PORT OUT
MASK REGISTER BIT 5
GPIO/PORT OUTPUT LATCH
GPIO INPUT
CONDITIONING
P28
GPIO IN
D
Q
GPIO/PORT OUT
MASK REGISTER BIT 4
GPIO/PORT OUTPUT LATCH
GPIO INPUT
CONDITIONING
P27
GPIO IN
D
Q
OR
MASK REGISTER BIT 3
GPIO/PORT OUT
GPIO/PORT OUTPUT LATCH
GPIO INPUT
CONDITIONING
P26
GPIO IN
D
Q
GPIO/PORT OUT
MASK REGISTER BIT 2
GPIO/PORT OUTPUT LATCH
GPIO INPUT
CONDITIONING
P25
GPIO IN
D
Q
GPIO/PORT OUT
MASK REGISTER BIT 1
GPIO/PORT OUTPUT LATCH
GPIO INPUT
CONDITIONING
P24
GPIO IN
D
GPIO/PORT OUT
GPIO/PORT OUTPUT LATCH
Q
MASK REGISTER LSB
CLOCK PULSE WHEN WRITING CONFIGURATION REGISTER WITH M BIT SET
Figure 5. Maskable GPIO Ports P24 Through P31
12
______________________________________________________________________________________
4-Wire-Interfaced, 2.5V to 5.5V, 20-Port and
28-Port I/O Expander
REGISTER
FUNCTION
POWER-UP CONDITION
ADDRESS
CODE (HEX)
Port Register
Bits 4 to 31
GPIO Output Low
Configuration
Register
REGISTER DATA
D7
D6
D5
D4
D3
D2
D1
D0
0x24 to
0x3F
X
X
X
X
X
X
X
0
Shutdown Enabled
Transition Detection Disabled
0x04
0
0
X
X
X
X
X
0
All Clear (Masked Off)
0x06
X
0
0
0
0
0
0
0
Port
Configuration
P7, P6, P5, P4: GPIO Inputs Without Pullup
0x09
1
0
1
0
1
0
1
0
Port
Configuration
P11, P10, P9, P8: GPIO Inputs Without Pullup
0x0A
1
0
1
0
1
0
1
0
Port
Configuration
P15, P14, P13, P12: GPIO Inputs Without
Pullup
0x0B
1
0
1
0
1
0
1
0
Port
Configuration
P19, P18, P17, P16: GPIO Inputs Without
Pullup
0x0C
1
0
1
0
1
0
1
0
Port
Configuration
P23, P22, P21, P20: GPIO Inputs Without
Pullup
0x0D
1
0
1
0
1
0
1
0
Port
Configuration
P27, P26, P25, P24: GPIO Inputs Without
Pullup
0x0E
1
0
1
0
1
0
1
0
Port
Configuration
P31, P30, P29, P28: GPIO Inputs Without
Pullup
0x0F
1
0
1
0
1
0
1
0
Input Mask
Register
X = unused bits; if read, zero results.
Table 5. Configuration Register Format
FUNCTION
ADDRESS CODE
(HEX)
Configuration Register
0x04
REGISTER DATA
D7
M
D6
0
D5
X
D4
X
D3
X
D2
X
D1
X
D0
S
Table 6. Shutdown Control (S Data Bit D0) Format
FUNCTION
ADDRESS CODE
(HEX)
Shutdown
Normal Operation
REGISTER DATA
0x04
D7
M
D6
0
D5
X
D4
X
D3
X
D2
X
D1
X
D0
0
0x04
M
0
X
X
X
X
X
1
______________________________________________________________________________________
13
MAX7301
Table 4. Power-Up Configuration
MAX7301
4-Wire-Interfaced, 2.5V to 5.5V, 20-Port and
28-Port I/O Expander
Table 7. Transition Detection Control (M Data Bit D7) Format
FUNCTION
ADDRESS CODE
(HEX)
Disabled
Enabled
REGISTER DATA
0x04
D7
0
D6
0
D5
X
D4
X
D3
X
D2
X
D1
X
D0
S
0x04
1
0
X
X
X
X
X
S
Table 8. Transition Detection Mask Register
FUNCTION
Mask
Register
14
REGISTER
ADDRESS
(HEX)
READ/
WRITE
REGISTER DATA
D7
D6
D5
D4
D3
D2
D1
D0
Read
0
Write
Unchanged
Port
30
mask
Port
29
mask
Port
28
mask
Port
27
mask
Port
26
mask
Port
25
mask
Port
24
mask
0x06
______________________________________________________________________________________
4-Wire-Interfaced, 2.5V to 5.5V, 20-Port and
28-Port I/O Expander
P12
6
31 P31
P9
7
P13
P10
N.C.
32 P4
31
5
32
P8
33
33 SCLK
34
4
35
DOUT
GND
ISET
V+
CS
DIN
SCLK
34 DIN
36
3
37
GND
GND
GND
35 CS
38
36 V+
2
DOUT
1
39
ISET
GND
40
TOP VIEW
P8
P12
1
30
2
29
P9
P13
P10
P14
3
28
4
27
30 P5
P11
P15
7
24
8
8
29 P30
P16
9
9
28 P6
P17
10
21 P24
P20 17
20 P23
P21 18
19 P22
25 SCLK
P12 5
24 P31
23
22
P27
P15 8
21 P28
21
P26
P16 9
20 P27
20
P19 16
26 DIN
DOUT 4
P13 6
P17 10
19 P26
P18 11
18 P25
P19 12
17 P24
P20 13
16 P23
P21 14
15 P22
19
22 P25
27 CS
GND 3
P25
N.C.
P18 15
18
23 P26
QFN
P24
P17 14
17
24 P27
16
P16 13
15
25 P28
14
P15 12
13
26 P7
12
P11 11
28 V+
P29
P7
P28
MAX7301
11
27 P29
25
P18
P19
P20
P21
P22
P23
P14 10
26
6
N.C.
MAX7301
5
P4
P31
P5
P30
P6
ISET 1
GND 2
P14 7
23 P30
MAX7301
22 P29
SSOP/DIP
SSOP
______________________________________________________________________________________
15
MAX7301
Pin Configurations
Package Information
2
SSOP.EPS
(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.)
1
INCHES
E
H
MILLIMETERS
DIM
MIN
MAX
MIN
MAX
A
0.068
0.078
1.73
1.99
A1
0.002
0.008
0.05
0.21
B
0.010
0.015
0.25
0.38
C
D
0.20
0.09
0.004 0.008
SEE VARIATIONS
E
0.205
e
0.212
0.0256 BSC
5.20
MILLIMETERS
INCHES
D
D
D
D
D
5.38
MIN
MAX
MIN
MAX
0.239
0.239
0.278
0.249
0.249
0.289
6.07
6.07
7.07
6.33
6.33
7.33
0.317
0.397
0.328
0.407
8.07
10.07
8.33
10.33
N
14L
16L
20L
24L
28L
0.65 BSC
H
0.301
0.311
7.65
7.90
L
0.025
0∞
0.037
8∞
0.63
0∞
0.95
8∞
N
A
C
B
e
L
A1
D
NOTES:
1. D&E DO NOT INCLUDE MOLD FLASH.
2. MOLD FLASH OR PROTRUSIONS NOT TO EXCEED .15 MM (.006").
3. CONTROLLING DIMENSION: MILLIMETERS.
4. MEETS JEDEC MO150.
5. LEADS TO BE COPLANAR WITHIN 0.10 MM.
PROPRIETARY INFORMATION
TITLE:
PACKAGE OUTLINE, SSOP, 5.3 MM
APPROVAL
DOCUMENT CONTROL NO.
21-0056
REV.
C
1
1
SSOP.EPS
MAX7301
4-Wire-Interfaced, 2.5V to 5.5V, 20-Port and
28-Port I/O Expander
36
E
DIM
A
A1
B
C
e
E
H
L
D
H
INCHES
MILLIMETERS
MAX
MIN
0.104
0.096
0.004
0.011
0.017
0.012
0.013
0.009
0.0315 BSC
0.299
0.291
0.398
0.414
0.040
0.020
0.598
0.612
MAX
MIN
2.65
2.44
0.29
0.10
0.44
0.30
0.23
0.32
0.80 BSC
7.40
7.60
10.11
10.51
0.51
15.20
1.02
15.55
1
TOP VIEW
D
A1
e
B
FRONT VIEW
A
C
0∞-8∞
L
SIDE VIEW
PROPRIETARY INFORMATION
TITLE:
PACKAGE OUTLINE, 36L SSOP, 0.80 MM PITCH
APPROVAL
DOCUMENT CONTROL NO.
21-0040
16
REV.
E
1
1
______________________________________________________________________________________
4-Wire-Interfaced, 2.5V to 5.5V, 20-Port and
28-Port I/O Expander
36L,40L, QFN.EPS
U
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.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 ____________________ 17
© 2004 Maxim Integrated Products
Printed USA
is a registered trademark of Maxim Integrated Products.
MAX7301
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.)
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