MAX7301ATL+ Datasheet MAX7301ATL+T, MAX7301AAI+, MAX7301ATL+ | P4-P6

MAX7301

4-Wire-Interfaced, 2.5V to 5.5V, 20-Port and

28-Port I/O Expander

4 _______________________________________________________________________________________

OPERATING SUPPLY CURRENT

vs. TEMPERATURE

MAX7301 toc01

TEMPERATURE (°C)

SUPPLY CURRENT (mA)

97.570.042.515.0-12.5

0.04

0.08

0.12

0.16

0.20

0.24

0.28

0.32

0.36

0.40

-40.0 125.0

V+ = 2.5V TO 5.5V

NO LOAD

ALL PORTS

OUTPUT (1)

ALL PORTS

OUTPUT (0)

ALL PORTS INPUT HIGH

SHUTDOWN SUPPLY CURRENT

vs. TEMPERATURE

MAX7301 toc02

TEMPERATURE (°C)

SUPPLY CURRENT (µA)

97.570.042.515.0-12.5

-40.0 125.0

V+ = 5.5V

V+ = 3.3V

V+ = 2.5V

OPERATING SUPPLY CURRENT

vs. V+ (OUTPUTS UNLOADED)

MAX7301 toc03

V+ (V)

SUPPLY CURRRENT (mA)

5.04.54.03.53.02.5

1.0

0.1

2.0 5.5

ALL PORTS OUTPUT (1)

ALL PORTS OUTPUT (0)

ALL PORTS INPUT

(PULLUPS DISABLED)

GPO SINK CURRENT vs. TEMPERATURE

(OUTPUT = 0)

MAX7301 toc04

TEMPERATURE (°C)

PORT SINK CURRENT (mA)

97.570.0-12.5 15.0 42.5

-40.0 125.0

V+ = 2.5V TO 5.5V, V

PORT

= 0.6V

GPO SHORT-CIRCUIT CURRENT

vs. TEMPERATURE

MAX7301 toc07

TEMPERATURE (°C)

PORT CURRENT (mA)

97.570.042.515.0-12.5

100

-40.0 125.0

GPO = 0, PORT

SHORTED TO V+

GPO = 1, PORT

SHORTED TO GND

GPO SOURCE CURRENT vs. TEMPERATURE

(OUTPUT = 1)

MAX7301 toc05

TEMPERATURE (°C)

PORT SOURCE CURRENT (mA)

97.570.042.515.0-12.5

-40.0 125.0

PORT

= 1.4

V+ = 5.5V

V+ = 3.3V

V+ = 2.5V

GPI PULLUP CURRENT

vs. TEMPERATURE

MAX7301 toc06

TEMPERATURE (°C)

PULLUP CURRENT (µA)

97.570.042.515.0-12.5

100

1000

-40.0 125.0

V+ = 5.5V

V+ = 3.3V

V+ = 2.5V

__________________________________________Typical Operating Characteristics

= +25°C, unless otherwise noted.)

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 and 40-pin MAX7301ATL

have 28 ports, P4 to P31. The 28-pin MAX7301AAI is

offered in 20 ports, 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.

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).

MAX7301

4-Wire-Interfaced, 2.5V to 5.5V, 20-Port and

28-Port I/O Expander

_______________________________________________________________________________________ 5

36 SSOP

28 SSOP

TQFN

NAME FUNCTION

1136 ISET

Bias Current Setting. Connect I

SET

to GND through a resistor (R

ISET

) value of

39kΩ to 120kΩ.

2, 3 2, 3

37, 38, 39

GND Ground

4440 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.

——

11, 20, 31

N.C. No Connection. Not internally connected.

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

——PAD

Exposed

Pad

Exposed Pad on Package Underside. Connect to GND.

Pin Description

MAX7301

Serial Interface

The MAX7301 communicates through an SPI-compati-

ble 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

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

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 connect-

ing 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 togeth-

er. 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

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

6 _______________________________________________________________________________________

Table 1. Port Configuration Map

ADDRESS

CODE (HEX)

D7 D6 D5 D4 D3 D2 D1

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

Table 2. Port Configuration Matrix

PORT

CONFIGURATION

BIT PAIR

MODE

FUNCTION

PORT

(0x20–0x5F)

(0xA0–0xDF)

PIN BEHAVIOR

ADDRESS

CODE

(

HEX

)

UPPER

LOWER

DO NOT USE THIS SETTING

0x09 to 0x0F

Active-low logic output

Output

GPIO Output

Active-high logic output

0x09 to 0x0F

Input

GPIO Input

Without Pullup

Schmitt logic input

0x09 to 0x0F

Input

GPIO Input with Pullup

input logic level

Schmitt logic input with pullup

0x09 to 0x0F

P1-P3 P4-P6 P7-P9 P10-P12 P13-P15 P16-P17

MAX7301ATL+

Mfr. #:

Buy MAX7301ATL+

Manufacturer:

Maxim Integrated

Description:

Interface - I/O Expanders 2.5-5.5V 20/28 Port I/O Expander

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New from this manufacturer.

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MAX7301ATL+

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