MAXIM MAX7327 User Manual

General Description

The MAX7327, a 2-wire serial-interfaced peripheral,
features 12 push-pull outputs and four configurable
open-drain I/O ports with selectable internal pullups
and transition detection. Ports are overvoltage protect­ed to +6V, independent of supply voltage.

The four I/O ports configured as inputs are continuously
monitored for state changes (transition detection). State
changes are indicated by the open-drain, +6V-tolerant
INT output. The interrupt is latched, detecting transient
changes. When the MAX7327 is subsequently accessed
through the serial interface, any pending interrupt is
cleared. The 12 push-pull and the four open-drain out­puts are rated to sink 20mA, and are capable of driving
LEDs. The RST input clears the serial interface, terminat­ing any I2C communication to or from the MAX7327.

The MAX7327 uses two address inputs with four-level
logic to allow 16 I

2

C slave addresses. The slave
address also determines the power-up logic state for
the I/O ports, and enables or disables internal 40kΩ
pullups in groups of two ports.

The MAX7327 is one device in a family of pin-compatible
port expanders with a choice of input ports, open-drain
I/O ports, and push-pull output ports (see Table 1).

The MAX7327 is available in the 24-pin QSOP and
TQFN packages, and is specified over the -40°C to
+125°C automotive temperature range.

Applications

Features

♦ 400kHz I2C Serial Interface
♦ +1.71V to +5.5V Operating Voltage
♦ 12 Push-Pull Output Ports, Rated at 20mA Sink

Current

♦ 4 Open-Drain I/O Ports, Rated at 20mA Sink Current
♦ I/O Ports are Overvoltage Protected to +6V
♦ Selectable I/O Port Power-Up Default Logic States
♦ Transient Changes are Latched, Allowing Detection

Between Read Operations

♦ INT Output Alerts Changes on Inputs
♦ AD0 and AD2 Inputs Select from 16 Slave

Addresses

♦ Low 0.6µA (typ) Standby Current
♦ -40°C to +125°C Temperature Range

MAX7327

I2C Port Expander with 12 Push-Pull

Outputs and 4 Open-Drain I/Os

________________________________________________________________ Maxim Integrated Products 1

19-3805; Rev 0; 8/06

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.

EVALUATION KIT

AVAILABLE

Ordering Information

PART

TEMP RANGE

PIN-PACKAGE

PKG

CODE

MAX7327AEG+

24 QSOP

E24-1

MAX7327ATG+

24 TQFN - E P **
( 4m m x 4m m )

T2444-3

MAX7327AATG+

24 TQFN - E P **

T243A3-1

Typical Application Circuit and Functional Diagram appear
at end of data sheet.

Selector Guide

PART

INTERRUPT

MASK

OPEN­DRAIN

PUSH-PULL

OUTPUTS

MAX7324

8 Yes — 8

MAX7325

—

8

MAX7326

4 Yes — 12

MAX7327

—

12

Cell Phones

SAN/NAS

Servers

Notebooks

Satellite Radio

Automotive

+Denotes lead-free package.
**EP = Exposed pad.

TQFN (4mm x 4mm)

TOP VIEW

MAX7327

19

20

21

22

12 345 6

18 17 16 15 14 13

23

24

12

11

10

9

8

7

SCL

V+

SDA

INT

AD2

O0+O1

P2

P3

P4

P5

AD0

O15

O13

O12

O11

RST

O10

O8

O9

GND

O6

O7

O14

EXPOSED PADDLE

Pin Configurations

Pin Configurations continued at end of data sheet.

-40°C to +125°C

-40°C to +125°C

-40°C to +125°C
( 3.5m m x 3.5m m )

INPUTS

OUTPUTS

Up to 8

Up to 4

Up to 8

Up to 4

MAX7327

I2C Port Expander with 12 Push-Pull
Outputs and 4 Open-Drain I/Os

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.

(All voltages referenced to GND.)

Supply Voltage V+....................................................-0.3V to +6V

SCL, SDA, AD0, AD2, RST, INT, P2–P5 ..................-0.3V to +6V

O0, O1, O6–O15 .............................................-0.3V to V

+

+ 0.3V

O0, O1, O6–O15 Output Current .....................................±25mA

P2–P5 Sink Current ............................................................25mA

SDA Sink Current ...............................................................10mA

INT Sink Current .................................................................10mA

Total V+ Current .................................................................50mA

Total GND Current ...........................................................100mA

Continuous Power Dissipation (T

A

= +70°C)

24-Pin QSOP (derate 9.5mW/°C over +70°C)...........761.9mW

24-Pin TQFN (derate 20.8mW/°C over +70°C) .......1666.7mW

Operating Temperature Range .........................-40°C to +125°C

Junction Temperature......................................................+150°C

Storage Temperature Range .............................-65°C to +150°C

Lead Temperature (soldering, 10s) .................................+300°C

DC ELECTRICAL CHARACTERISTICS

(V+ = +1.71V to +5.5V, TA= -40°C to +125°C, unless otherwise noted. Typical values are at V+ = +3.3V, TA= +25°C.) (Note 1)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Operating Supply Voltage V+ TA = -40°C to +125°C 1.71 5.50 V

Power-On Reset Voltage V

Standby Current
(Interface Idle)

Supply Current
(Interface Running)

Input High-Voltage
SDA, SCL, AD0, AD2, RST, P2–P5

Input Low-Voltage
SDA, SCL, AD0, AD2, RST, P2–P5

Input Leakage Current
SDA, SCL, AD0, AD2, RST, P2–P5

Input Capacitance
SDA, SCL, AD0, AD2, RST, P2–P5

Output Low Voltage
O8–O15, P0, P7

Output High Voltage
O0, O1, O6–O15, P2–P5

Output Low-Voltage SDA V
Output Low-Voltage INT V

Port Input Pullup Resistor R

I

POR

I

STB

V

V

IH

V

V

OLSDAISINK

OLINTISINK

V+ falling 1.6 V

SCL and SDA and other
digital inputs at V+

f

= 400kHz; other

I+

OL

OH

PU

SCL

digital inputs at V+

V+ < 1.8V 0.8 x V+

IH

V+ ≥ 1.8 V 0.7 x V+

V+ < 1.8V 0.2 x V+

IL

V+ ≥ 1.8 V 0.3 x V+
SDA, SCL, AD0, AD2, RST, P0–P7 at V+

, I

IL

or GND, internal pullup disabled

V+ = 1.71V, I

V+ = 1.71V, I

V+ = 2.5V, I

V+ = 2.5V, I

V+ = 3.3V, I

V+ = 3.3V, I

V+ = 5V, I

V+ = 5V, I

V+ = +1.71V, I

V+ = +2.5V, I

V+ = +3.3V, I

V+ = +5V, I

SINK

SINK

= 6mA 250 mV

= 5mA 130 250 mV

TA = -40°C to
+125°C

TA = -40°C to
+125°C

-0.2 +0.2 µA

= 5mA (QSOP) 90 180

SINK

= 5mA (TQFN) 90 230

SINK

= 10mA (QSOP) 110 210

SINK

= 10mA (TQFN) 110 260

SINK

= 15mA (QSOP) 130 230

SINK

= 15mA (TQFN) 130 280

SINK

= 20mA (QSOP) 140 250

= 20mA (TQFN) 140 300

= 2mA V+ - 250 V+ - 30

SOURCE

= 5mA V+ - 360 V+ - 70

SOURCE

= 5mA V+ - 260 V+ - 100

SOURCE

= 10mA V+ - 360 V+ - 120

SOURCE

0.6 1.9 µA

23 55 µA

10 pF

25 40 55 kΩ

V

V

mV

mV

MAX7327

I2C Port Expander with 12 Push-Pull

Outputs and 4 Open-Drain I/Os

_______________________________________________________________________________________ 3

PORT AND INTERRUPT INT TIMING CHARACTERISTICS

(V+ = +1.71V to +5.5V, TA= -40°C to +125°C, unless otherwise noted. Typical values are at V+ = +3.3V, TA= +25°C.) (Note 1)

TIMING CHARACTERISTICS

(V+ = +1.71V to +5.5V, TA= -40°C to +125°C, unless otherwise noted. Typical values are at V+ = +3.3V, TA= +25°C.) (Note 1)

Note 1: All parameters tested at TA= +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. tRand tFmeasured between 0.3 x V+ and 0.7 x V+ with I

SINK

≤ 6mA.

Note 5: Input filters on the SDA and SCL inputs suppress noise spikes less than 50ns.

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Port Output Data Valid t

Port Input Setup Time t

Port Input Hold Time t

INT Input Data Valid Time t
INT Reset Delay Time from STOP t

INT Reset Delay Time from

Acknowledge

PPV

PSU

PH

t

CL ≤ 100pF 4 µs

CL ≤ 100pF 0 µs

CL ≤ 100pF 4 µs

CL ≤ 100pF 4 µs

IV

CL ≤ 100pF 4 µs

IP

CL ≤ 100pF 4 µs

IR

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

RST Pulse Width t

RST Rising to START Condition

Setup Time

t

HD, STA

t

SU, STA

SU, STO

HD, DAT

SU, DAT

SCL

t

BUF

LOW

HIGH

t

R

t

F

F,TX

SP

C

b

W

t

RST

1.3 µs

0.6 µs

0.6 µs

0.6 µs

(Note 2) 0.9 µs

100 ns

1.3 µs

0.7 µs

(Notes 3, 4)

(Notes 3, 4)

(Notes 3, 4)

(Note 5) 50 ns

(Note 3) 400 pF

500 ns

20 +

0.1C

20 +

0.1C

20 +

0.1C

1µs

400 kHz

300 ns

b

300 ns

b

250 ns

b

MAX7327

I2C Port Expander with 12 Push-Pull
Outputs and 4 Open-Drain I/Os

4 _______________________________________________________________________________________

Typical Operating Characteristics

(TA = +25°C, unless otherwise noted.)

STANDBY CURRENT

vs. TEMPERATURE

TEMPERATURE (°C)

STANDBY CURRENT (μA)

MAX7327 toc01

-40 -25 -10 5 20 35 50 65 80 95 110 125

0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

2.0

V+ = +3.3V

V+ = +5.0V

V+ = +2.5V

V+ = +1.71V

f

SCL

= 0kHz

SUPPLY CURRENT
vs. TEMPERATURE

TEMPERATURE (°C)

SUPPLY CURRENT (μA)

MAX7327 toc02

-40 -25 -10 5 20 35 50 65 80 95 110 125

0

10

20

30

40

50

60

V+ = +3.3V

V+ = +5.0V

V+ = +2.5V

V+ = +1.71V

f

SCL

= 400kHz

OUTPUT VOLTAGE LOW

vs. TEMPERATURE

TEMPERATURE (°C)

OUTPUT VOLTAGE LOW (V)

MAX7327 toc03

-40 -25 -10 5 20 35 50 65 80 95 110 125

0

0.05

0.10

0.15

0.20

0.25

V+ = +3.3V
I

SINK

= 15mA

V+ = +5.0V
I

SINK

= 20mA

V+ = +2.5V
I

SINK

= 10mA

V+ = +1.71V
I

SINK

= 5mA

V+ = +1.62V
I

SINK

= 4mA

OUTPUT VOLTAGE HIGH

vs. TEMPERATURE

TEMPERATURE (°C)

OUTPUT VOLTAGE HIGH (V)

MAX7327 toc04

-40 -25 -10 5 20 35 50 65 80 95 110 125

0

1

2

3

4

5

6

V+ = +3.3V
I

SOURCE

= 5mA

V+ = +5.0V
I

SOURCE

= 10mA

V+ = +2.5V I

SOURCE

= 5mA

V+ = +1.71V I

SOURCE

= 2mA

Pin Description

PIN

QSOP TQFN

122 INT Active-Low Interrupt Output. INT is an open-drain output.
223 RST Active-Low Reset Input. Drive RST low to clear the 2-wire interface.

3, 21 24, 18 AD2, AD0

4, 5, 10,

11, 13–20

6–9 3–6 P2–P5 P2–P5 Open-Drain I/Os

12 9 GND Ground

22 19 SCL I2C-Compatible Serial Clock Input

23 20 SDA I2C-Compatible Serial Data I/O

24 21 V+ Positive Supply Voltage. Bypass V+ to GND with a 0.047µF ceramic capacitor.

— EP EP Exposed Pad. Connect exposed pad to GND.

1, 2, 7, 8,

10–17

NAME 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 Tables 2 and 3).

O0, O1,

O6–O15

Output Ports. O0, O1, O6–O15 are push-pull outputs rated at 20mA.

Detailed Description

MAX7319–MAX7329 Family Comparison

The MAX7324–MAX7327 family consists of four pin­compatible, 16-port expanders that integrate the func­tions of the MAX7320 and one of either the MAX7319,
MAX7321, MAX7322, or MAX7323.

Functional Overview

The MAX7327 is a general-purpose port expander
operating from a +1.71V to +5.5V supply that provides
12 push-pull output ports with a 20mA sink, 10mA
source drive capability, and four open-drain I/O ports
with a 20mA sink capability. The four open-drain out­puts are overvoltage protected to +6V.

The MAX7327 is set to two of 32 I

2

C slave addresses
(see Tables 2 and 3) using address inputs AD2 and
AD0, and is accessed over an I2C serial interface up to
400kHz. Eight push-pull outputs use a different slave
address from the other four push-pull outputs and the
open-drain I/Os. The eight push-pull outputs, O8–O15,
use the 101xxxx addresses while the four outputs O0,
O1, O6, and O7 and the open-drain I/Os P2–P5 use
addresses with 110xxxx. The RST input clears the serial
interface in case of a bus lockup, terminating any serial
transaction to or from the MAX7327.

Any of the four open-drain ports can be configured as a
logic input by setting the port output logic-high (logic­high for an open-drain output is high impedance).
When the MAX7327 is read through the serial interface,
the actual logic levels at the ports are read back.

MAX7327

I2C Port Expander with 12 Push-Pull

Outputs and 4 Open-Drain I/Os

_______________________________________________________________________________________ 5

Table 1. MAX7319–MAX7329 Family Comparison

2

C

I

PART

16-PORT EXPANDERS

SLAVE

ADDRESS

INPUTS

INPUT

INTERRUPT

MASK

OPEN­DRAIN

OUTPUTS

PUSH-

PULL

OUTPUTS

CONFIGURATION

8 inputs and 8 push-pull outputs version:

8 input ports with programmable latching transition
detection interrupt and selectable pullups.

MAX7324 8 Yes — 8

101xxxx

and

110xxxx

MAX7325

Up to 8 — Up to 8 8

8 push-pull outputs with selectable default logic
levels.

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 if only for
a transient) since the ports were last read.
8 I/O and 8 push-pull outputs version:
8 open-drain I/O ports with latching transition
detection interrupt and selectable pullups.

8 push-pull outputs with selectable default logic
levels.

Open-drain outputs can level shift the logic-high
state to a higher or lower voltage than V+ using
external pullup resistors, but pullups draw current
when output is low. Any open-drain port can be used
as an input by setting the open-drain output to logic­high. Transition flags identify which open-drain port
inputs have changed (even if only for a transient)
since the ports were last read.

MAX7327

I2C Port Expander with 12 Push-Pull
Outputs and 4 Open-Drain I/Os

6 _______________________________________________________________________________________6 _______________________________________________________________________________________6 _______________________________________________________________________________________

Table 1. MAX7319–MAX7329 Family Comparison (continued)

2

PART

C

I

SLAVE

ADDRESS

INPUTS

INPUT

INTERRUPT

MASK

OPEN­DRAIN

OUTPUTS

PUSH-

PULL

OUTPUTS

CONFIGURATION

4 input-only, 12 push-pull output versions:
4 input ports with programmable latching transition
detection interrupt and selectable pullups.

MAX7326 4 Yes — 12

101xxxx

and

110xxxx

MAX7327

8-PORT EXPANDERS

MAX7319 110xxxx 8 Yes — —

Up to 4 — Up to 4 12

12 push-pull outputs with selectable default logic
levels.

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 if only for
a transient) since the ports were last read.
4 I/O, 12 push-pull output versions:
4 open-drain I/O ports with latching transition
detection interrupt and selectable pullups.

12 push-pull outputs with selectable default logic
levels.

Open-drain outputs can level shift the logic-high
state to a higher or lower voltage than V+ using
external pullup resistors, but pullups draw current
when output is low. Any open-drain port can be used
as an input by setting the open-drain output to logic­high. Transition flags identify which open-drain port
inputs have changed (even if only for a transient)
since the ports were last read.

Input-only versions:
8 input ports with programmable latching transition
detection interrupt and selectable pullups.

Output-only versions:

MAX7320 101xxxx — — — 8

MAX7321 110xxxx Up to 8 — Up to 8 —

MAX7322 110xxxx 4 Yes — 4

8 push-pull outputs with selectable power-up default
levels.

I/O versions:
8 open-drain I/O ports with latching transition
detection interrupt and selectable pullups.

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
levels.

MAX7327

I2C Port Expander with 12 Push-Pull

Outputs and 4 Open-Drain I/Os

_______________________________________________________________________________________ 7

The four open-drain ports offer latching transition
detection functionality when used as inputs. All input
ports are continuously monitored for changes. An input
change sets 1 of 4 flag bits that identify the changed
input(s). All flags are cleared upon a subsequent read
or write transaction to the MAX7327.

A latching interrupt output INT automatically flags data
changes on any of the I/O ports used as inputs through
an interrupt mask register. Data changes on any input
port forces INT to a logic-low. The interrupt output INT
is deasserted when the MAX7327 is next accessed
through the serial interface.

Internal pullup resistors to V+ are selected by the
address select inputs, AD0 and AD2. Pullups are enabled
on the input ports in groups of two (see Table 2). Use the
slave address selection to ensure that I/O ports used
as inputs are logic-high on power-up. I/O ports with
internal pullups enabled default to a logic-high output
state. I/O ports with internal pullups disabled default to
a logic-low output state.

Output port power-up logic levels are selected by the
address select inputs AD0 and AD2. Ports default to
logic-high or logic-low on power-up in groups of two
(see Tables 2 and 3).

Initial Power-Up

On power-up, the default states of the 12 push-pull out­put ports and the four open-drain I/O ports are set
according to the I2C slave address selection inputs,
AD0 and AD2 (see Tables 2 and 3). For I/O ports used
as inputs, ensure that the default states are logic-high;
therefore, the I/O ports power up in the high-imped­ance state. All I/O ports configured with pullups
enabled also have a logic-high default state. On power-

up, the transition detection logic is reset, and INT is
deasserted. The transition flags are cleared, indicating
no data changes.

Power-On Reset (POR)

The MAX7327 contains an integral POR circuit that
ensures all registers are reset to a known state on
power-up. When V+ rises above V

POR

(1.6V max), the
POR circuit releases the registers and 2-wire interface
for normal operation. When V+ drops to less than V

POR

,
the MAX7327 resets all register contents to the POR
defaults (Tables 2 and 3).

RST

Input

The active-low RST input operates as a hardware reset
that voids any I

2

C transaction involving the MAX7327,

forcing the MAX7327 into the I2C STOP condition. A
reset does not affect the interrupt output (INT).

Standby Mode

When the serial interface is idle, the MAX7327 automat­ically enters standby mode drawing minimal supply
current.

Slave Address, Power-Up Default Logic

Levels, and Input Pullup Selection

Address inputs AD0 and AD2 determine the MAX7327
slave address and select which inputs have pullup
resistors. Pullups are enabled on the input ports in
groups of two (see Table 2).

The MAX7327 slave address is determined on each I2C
transmission, regardless of whether the transmission is
actually addressing the MAX7327. The MAX7327 distin­guishes whether address inputs AD0 and AD2 are con­nected to SDA or SCL instead of fixed-logic levels V+
or GND during the transmission. The MAX7327 slave

Table 1. MAX7319–MAX7329 Family Comparison (continued)

2

I

C

PART

MAX7323 110xxxx Up to 4 — Up to 4 4

MAX7328
MAX7329

SLAVE

ADDRESS

0100xxx
0111xxx

INPUTS

Up to 8 — Up to 8 —

INPUT

INTERRUPT

MASK

OPEN­DRAIN

OUTPUTS

PUSH-

PULL

OUTPUTS

4 I/O, 4 output-only versions:
4 open-drain I/O ports with latching transition
detection interrupt and selectable pullups.
4 push-pull outputs with selectable power-up default
levels.

PCF8574-, PCF8574A-compatible versions:
8 open-drain I/O ports with nonlatching transition
detection interrupt and pullups on all ports.

CONFIGURATION