MAXIM MAX7300 User Manual

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General Description

The MAX7300 compact, serial-interfaced, I/O expan­sion 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 as either 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 MAX7300 is controlled through an I2C™-compatible
2-wire serial interface, and uses four-level logic to allow
16 I2C addresses from only two select pins.

The MAX7300AAX and MAX7300AGL have 28 ports
and are available in 36-pin SSOP and 40-pin QFN pack­ages, respectively. The MAX7300AAI and MAX7300ANI
have 20 ports and are available in 28-pin SSOP and 28­pin DIP packages, respectively.

Applications

White Goods Industrial Controllers

Automotive System Monitoring

Features

♦ 400kbps I2C-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

MAX7300

2-Wire-Interfaced, 2.5V to 5.5V, 20-Port or

28-Port I/O Expander

________________________________________________________________ Maxim Integrated Products 1

19-2413; Rev 1; 2/03

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.

Ordering Information

I2C is a trademark of Philips Corp.

P5

P4

P7
P8

P6

P10

P9

P12
P13

P11

P15

P14

P17
P18

P16

P20

P19

I/O 5

I/O 4

I/O 7
I/O 8

I/O 6

I/O 10

I/O 9

I/O 12
I/O 13

I/O 11

I/O 15

I/O 14

I/O 17
I/O 18

I/O 16

I/O 20

I/O 19

I/O 21
I/O 22

I/O 23

P22
P23

P21

36

2

3

4

33

35

34

29
27

31

24

25

22
21

23

V+

GND

GND

AD0

AD1

SCL

P30
P29

P31

P27

P28

P25
P24

P26

32
30

26

5
7
9

28

6
8

11

10
12

14
15

13

17

16

19
20

18

SDA

MAX7300AAX

3V

DATA

CLOCK

I/O 24
I/O 25

I/O 27

I/O 26

I/O 29
I/O 30

I/O 28

I/O 31

47nF

39kΩ

1

ISET

Typical Operating Circuit

Pin Configurations

Pin Configurations continued at end of data sheet.

PART TEMP RANGE PIN-PACKAGE

MAX7300ANI -40°C to +125°C 28 DIP

MAX7300AAI -40°C to +125°C 28 SSOP

MAX7300AAX -40°C to +125°C 36 SSOP

MAX7300AGL -40°C to +125°C 40 QFN

TOP VIEW

ISET

1

GND

2

GND

3

AD0

4

P12

5

P13

6

P14

7

P15

8

P16

9

P17

10

P18

11

P19

12

P20

13

P21

14

MAX7300

SSOP/DIP

28

27

26

25

24

23

22

21

20

19

18

17

16

15

V+

AD1

SCL

SDA

P31

P30

P29

P28

P27

P26

P25

P24

P23

P22

MAX7300

2-Wire-Interfaced, 2.5V to 5.5V, 20-Port or
28-Port I/O Expander

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

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

Voltage (with respect to GND)

V+ .............................................................................-0.3V to +6V

SCL, SDA, AD0, AD1................................................-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 aboveT

A

= +70°C)..1860mW

Operating Temperature Range

(T

MIN

to 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

ELECTRICAL CHARACTERISTICS

(Typical Operating Circuit, V+ = 2.5V to 5.5V, TA= T

MIN

to T

MAX

, unless otherwise noted.) (Note 1)

Operating Supply Voltage V+ 2.5 5.5 V

Operating Supply Current I

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

I

SHDN

GPOH

All digital inputs at
V+ or GND

All ports programmed
as outputs high, no
load, all other inputs
at V+ or GND

TA = +25°C 5.5 8

TA = -40°C to +85°C10Shutdown Supply Current

to T

T

MIN

TA = +25°C 180 240

TA = -40°C to +85°C 260

to T

T

MIN

MAX

MAX

11

280

µA

µA

All ports programmed

Operating Supply Current I

Operating Supply Current I

INPUTS AND OUTPUTS

Logic High Input Voltage
Port Inputs

Logic Low Input Voltage
Port Inputs

Input Leakage Current IIH, I

GPIO Input Internal Pullup to V+ I

Hysteresis Voltage GPIO Inputs ∆V

GPOL

GPI

V

V

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

IH

IL

GPIO inputs without pullup,

IL

PU

I

= V+ to GND

V

PORT

V+ = 2.5V 12 19 30

V+ = 5.5V 80 120 180

TA = +25°C 170 210

TA = -40°C to +85°C 230

T

to T

MIN

MAX

TA = +25°C 110 135

TA = -40°C to +85°C 140

to T

T

MIN

MAX

0.7 x
V+

-100 ±1 +100 nA

0.3 V

240

145

0.3 x
V+

µA

µA

V

V

µA

MAX7300

2-Wire-Interfaced, 2.5V to 5.5V, 20-Port or

28-Port I/O Expander

_______________________________________________________________________________________ 3

ELECTRICAL CHARACTERISTICS (continued)

(Typical Operating Circuit, V+ = 2.5V to 5.5V, TA= T

MIN

to T

MAX

, unless otherwise noted.) (Note 1)

TIMING CHARACTERISTICS (Figure 2)

(V+ = 2.5V to 5.5V, TA= T

MIN

to T

MAX

, unless otherwise noted.) (Note 1)

Output High Voltage V

Port Sink Current I

Output Short-Circuit Current I

Input High-Voltage SDA, SCL,
AD0, AD1

Input Low-Voltage SDA, SCL,
AD0, AD1

Input Leakage Current SDA, SCL IIH, I

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

OH

OL

OLSC

V

IH

V

IL

IL

Input Capacitance (Note 2) 10 pF

Output Low-Voltage SDA V

OL

GPIO outputs, I
T

= -40°C to +85°C

A

GPIO outputs, I

= T

T

A

MIN

V

= 0.6V 2 10 18 mA

PORT

= 2mA,

SOURCE

= 1mA,

SOURCE

to T

MAX

(Note 2)

V+ -

0.7

V+ -

0.7

Port configured output low, shorted to V+ 2.75 11 20 mA

0.7 x
V+

0.3 x
V+

-50 +50 nA

I

= 6mA 0.4 V

SINK

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Serial Clock Frequency f

Bus Free Time Between a STOP
and a START Condition

Hold Time (Repeated) START
Condition

Repeated START Condition
Setup Time

STOP Condition Setup Time t

Data Hold Time t

Data Setup Time t

SCL Clock Low Period t

SCL Clock High Period t

Rise Time of Both SDA and SCL
Signals, Receiving

Fall Time of Both SDA and SCL
Signals, Receiving

Fall Time of SDA Transmitting t

Pulse Width of Spike Suppressed t

Capacitive Load for Each Bus
Line

SCL

t

BUF

t

HD, STA

t

SU, STA

SU, STO

HD, DAT

SU, DAT

LOW

HIGH

F,TX

C

(Note 3) 15 900 ns

(Notes 2, 4)

t

R

(Notes 2, 4)

t

F

(Notes 2, 5)

(Notes 2, 6) 0 50 ns

SP

(Note 2) 400 pF

b

400 kHz

1.3 µs

0.6 µs

0.6 µs

0.6 µs

100 ns

1.3 µs

0.7 µs

20 +

0.1C

20 +

0.1C

20 +

0.1C

b

b

b

300 ns

300 ns

250 ns

V

V

V

MAX7300

2-Wire-Interfaced, 2.5V to 5.5V, 20-Port or
28-Port I/O Expander

4 _______________________________________________________________________________________

__________________________________________Typical Operating Characteristics

(R

ISET

= 39kΩ, TA = +25°C, unless otherwise noted.)

TIMING CHARACTERISTICS (Figure 2) (continued)

(V+ = 2.5V to 5.5V, TA= T

MIN

to T

MAX

, unless otherwise noted.) (Note 1)

Note 1: All parameters tested at T

A

= +25°C. Specifications over temperature are guaranteed by design.

Note 2: Guaranteed by design.
Note 3: 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 4: C

b

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

Note 5: I

SINK

≤ 6mA. Cb= total capacitance of one bus line in pF. tRand tFmeasured between 0.3V+ and 0.7V+.

Note 6: Input filters on the SDA and SCL inputs suppress noise spikes less than 50ns.

OPERATING SUPPLY CURRENT

vs. TEMPERATURE

0.40

V+ = 2.5V TO 5.5V

0.36

NO LOAD

0.32

0.28

ALL PORTS
OUTPUT (1)

0.24

0.20

0.16

0.12

SUPPLY CURRENT (mA)

0.08

0.04

0

-40.0 125.0
TEMPERATURE (°C)

ALL PORTS
OUTPUT (0)

ALL PORTS INPUT HIGH

MAX7300 toc01

SUPPLY CURRENT (µA)

97.570.042.515.0-12.5

SHUTDOWN SUPPLY CURRENT

vs. TEMPERATURE

8

7

V+ = 3.3V

6

5

4

3

-40.0 125.0

V+ = 5.5V

V+ = 2.5V

97.570.042.515.0-12.5

TEMPERATURE (°C)

1

MAX7300 toc02

SUPPLY CURRENT ( mA)

0.1

OPERATING SUPPLY CURRENT vs. V+

(OUTPUTS UNLOADED)

ALL PORTS OUTPUT (1)

ALL PORTS OUTPUT (0)

ALL PORTS INPUT

(PULLUPS DISABLED)

2.0 5.5
V+ (V)

5.04.54.03.53.02.5

MAX7300 toc03

MAX7300

2-Wire-Interfaced, 2.5V to 5.5V, 20-Port or

28-Port I/O Expander

_______________________________________________________________________________________ 5

Typical Operating Characteristics (continued)

(R

ISET

= 39kΩ, TA = +25°C, unless otherwise noted.)

GPO SINK CURRENT vs. TEMPERATURE

18

V+ = 2.5V TO 5.5V, V

16

14

12

10

8

PORT SINK CURRENT (mA)

6

4

2

-40.0 125.0

GPI PULLUP CURRENT

1000

100

PULLUP CURRENT (µA)

10

-40.0 125.0

(OUTPUT = 0)

= 0.6V

PORT

TEMPERATURE (°C)

vs. TEMPERATURE

V+ = 5.5V

V+ = 3.3V

V+ = 2.5V

TEMPERATURE (°C)

GPO SOURCE CURRENT vs. TEMPERATURE

9

V

PORT

MAX7300 toc04

97.570.0-12.5 15.0 42.5

MAX7300 toc06

97.570.042.515.0-12.5

8

7

6

5

4

PORT SOURCE CURRENT (mA)

3

2

-40.0 125.0

100

10

PORT CURRENT (mA)

SHORTED TO GND

1

-40.0 125.0

(OUTPUT = 1)

= 1.4V

V+ = 5.5V

V+ = 3.3V

V+ = 2.5V

97.570.042.515.0-12.5

TEMPERATURE (°C)

GPO SHORT-CIRCUIT CURRENT

vs. TEMPERATURE

GPO = 0, PORT

SHORTED TO V+

GPO = 1, PORT

97.570.042.515.0-12.5

TEMPERATURE (°C)

MAX7300 toc05

MAX7300 toc07

MAX7300

2-Wire-Interfaced, 2.5V to 5.5V, 20-Port or
28-Port I/O Expander

6 _______________________________________________________________________________________

Detailed Description

The MAX7300 general-purpose input/output (GPIO)
peripheral provides up to 28 I/O ports, P4 to P31, con­trolled through an I2C-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 MAX7300 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 to P30) to be monitored in any maskable combina­tion for changes in their logic status. A detected transi­tion is flagged through a status register bit, as well as an
interrupt pin (port P31), if desired.

The port configuration registers individually set the 28
ports, P4 to P31, as GPIO. A pair of bits in registers
0x09 through 0x0F sets each port’s configuration
(Tables 1 and 2).

The 36-pin MAX7300AAX and 40-pin MAX7300AGL
have 28 ports, P4 to P31. The 28-pin MAX7300ANI and
MAX7300AAI have 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 MAX7300 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 to P7,
P1 to P8, or P31 to P38 (P32 to P38 are nonexistent, so
the instructions to these bits are ignored).

Shutdown

When the MAX7300 is in shutdown mode, all ports are
forced to inputs, 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 MAX7300 is taken out of shutdown.
The MAX7300 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 8).

Pin Description

PIN

SSOP/DIP SSOP

1 1 36 ISET

2, 3 2, 3

4 4 40 AD0

QFN

37, 38, 39

NAME FUNCTION

GND Ground

5–24 ——P12–P31

— 5–32

25 33

26 34

27 35 34 AD1

28 36 35 V+

1–10, 12–19,

21–30

32

33

P4–P31

SDA I2C-Compatible Serial Data I/O

SCL I2C-Compatible Serial Clock Input

Bias Current Setting. Connect ISET to GND through a resistor (R
value of 39kΩ to 120kΩ.

Address Input 0. Sets device slave address. Connect to either GND,
V+, SCL, SDA to give four logic combinations. See Table 3.

I/O P or ts. P 12 to P 31 can b e confi g ur ed as p ush- p ul l outp uts, C M O S ­l og i c i np uts, or C M O S - l og i c i np uts w i th w eak p ul l up r esi stor .

I/O P or ts. P4 to P31 can be configured as p ush- p ul l outputs, CMOS­logic inputs, or CMOS-logic inputs with weak pullup resistor.

Address Input 1. Sets device slave address. Connect to either GND,
V+, SCL, SDA to give four logic combinations. See Table 3.

Positive Supply Voltage. Bypass V+ to GND with minimum 0.047µF
capacitor.

ISET

)

MAX7300

2-Wire-Interfaced, 2.5V to 5.5V, 20-Port or

28-Port I/O Expander

_______________________________________________________________________________________ 7

Serial Interface

Serial Addressing

The MAX7300 operates as a slave that sends and
receives data through an I2C-compatible 2-wire 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). A master (typ­ically a microcontroller) initiates all data transfers to and
from the MAX7300, and generates the SCL clock that
synchronizes the data transfer (Figure 2).

The MAX7300 SDA line operates as both an input and
an open-drain output. A pullup resistor, typically 4.7kΩ,
is required on SDA. The MAX7300 SCL line operates
only as an input. A pullup resistor, typically 4.7kΩ, is
required on SCL if there are multiple masters on the 2­wire interface, or if the master in a single-master system
has an open-drain SCL output.

Each transmission consists of a START condition
(Figure 3) sent by a master, followed by the MAX7300
7-bit slave address plus R/W bit (Figure 6), a register
address byte, one or more data bytes, and finally a
STOP condition (Figure 3).

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, it 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 3).

Bit Transfer

One data bit is transferred during each clock pulse.
The data on SDA must remain stable while SCL is high
(Figure 4).

Acknowledge

The acknowledge bit is a clocked 9th bit, which the
recipient uses to handshake receipt of each byte of
data (Figure 5). Thus, 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 MAX7300, the
MAX7300 generates the acknowledge bit since the

Table 1. Port Configuration Map

Table 2. Port Configuration Matrix

(

)

REGISTER

Port Configuration for P7, P6, P5, P4 0x09 P7 P6 P5 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

ADDRESS

CODE (HEX)

D7 D6 D5 D4 D3 D2 D1 D0

MODE FUNCTION

DO NOT USE THIS SETTING 0x09 to 0x0F 0 0

Output GPIO Output

Input

Input GPIO Input with Pullup Reading Port Schmitt logic input with pullup 0x09 to 0x0F 1 1

GPIO Input

without Pullup

PORT

REGISTER

Written Low

Written High

Reading Port Schmitt logic output 0x09 to 0x0F 1 0

Active-low logic output

Active-high logic output

PIN BEHAVIOR

REGISTER DATA

PORT

ADDRESS

CODE

HEX

0x09 to 0x0F 0 1

CONFIGURATION

BIT PAIR

UPPER LOWER