MAXIM MAX7325 User Manual

General Description

The MAX7325 2-wire serial-interfaced peripheral features
16 I/O ports. Ports are divided into eight push-pull out­puts and eight I/Os with selectable internal pullups and
transition detection. Eight ports are push-pull outputs
and eight I/Os may be used as a logic input or an open­drain output. Ports are overvoltage protected to +6V.

All I/O ports configured as inputs are continuously mon­itored for state changes (transition detection). State
changes are indicated by the INT output. The interrupt
is latched, allowing detection of transient changes.
When the MAX7325 is subsequently accessed through
the serial interface, any pending interrupt is cleared.
The open-drain outputs are rated to sink 20mA, and are
capable of driving LEDs. The RST input clears the serial
interface, terminating any I

2

C communication to or from

the MAX7325.

The MAX7325 uses two address inputs with four-level
logic to allow 16 I2C 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 four ports.

The MAX7325 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 MAX7325 is available in 24-pin QSOP and TQFN
packages and is specified over the -40°C to +125°C
automotive temperature range.

Applications

Cell Phones Notebooks
SAN/NAS Satellite Radio
Servers Automotive

Features

♦ 400kHz I2C Serial Interface
♦ +1.71V to +5.5V Operation
♦ 8 Push-Pull Outputs
♦ 8 Open-Drain I/O Ports, Rated to 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 Change on Inputs
♦ AD0 and AD2 Inputs Select from 16 Slave

Addresses

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

MAX7325

I2C Port Expander with 8 Push-Pull

and 8 Open-Drain I/Os

________________________________________________________________ Maxim Integrated Products 1

19-3807; Rev 0; 9/06

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

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

Selector Guide

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

Pin Configurations

Pin Configurations continued at end of data sheet.

TOP VIEW

SCL

SDA

V+

INT

RST

AD2

AD0

O15

O14

18 17 16 15 14 13

19

20

21

22

23

24

MAX7325

EXPOSED PADDLE

+

12 3456

P0

P1

TQFN (4mm x 4mm)

P2

P3

O13

O12

P4

O11

P5

12

O10

11

O9

10

O8

GND

9

P7

8

P6

7

PART TEMP RANGE PIN-PACKAGE

MAX7325AEG+ -40°C to +125°C 24 QSOP E24-1

MAX7325ATG+ -40°C to +125°C

24 TQFN-EP*
(4mm x 4mm)

PKG

CODE

T2444-3

PART INPUTS

MAX7324 8 Yes — 8

MAX7325 Up to 8 — Up to 8 8

MAX7326 4 Yes — 12

MAX7327 Up to 4 — Up to 4 12

INTERRUPT

MASK

OPEN­DRAIN

OUTPUTS

PUSH-PULL

OUTPUTS

MAX7325

I2C Port Expander with 8 Push-Pull
and 8 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, P0–P7 ...................-0.3V to +6V

O8–O15 ........................................................-0.3V to (V+ + 0.3V)

O8–O15 Output Current ...................................................±25mA

P0–P7 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

V

Power-On-Reset Voltage V

POR

V+ falling 1.6 V

Standby Current
(Interface Idle)

I

STB

SCL and SDA and other
digital inputs at V+

TA = -40°C to
+125°C

0.6 1.9 µA

Supply Current
(Interface Running)

I+

f

SCL

= 400kHz; other

digital inputs at V+

TA = -40°C to
+125°C

23 55 µA

V+ < 1.8V

Input High-Voltage

SDA, SCL, AD0, AD2, RST, P0–P7

V

IH

V+ ≥ 1.8V

V

V+ < 1.8V

Input Low-Voltage

SDA, SCL, AD0, AD2, RST, P0–P7

V

IL

V+ ≥ 1.8V

V

Input Leakage Current

SDA, SCL, AD0, AD2, RST, P0–P7

IIH, I

IL

SDA, SCL, AD0, AD2, RST, P0–P7 at V+ or
GND, internal pullup disabled

+0.2 µA

Input Capacitance

SDA, SCL, AD0, AD2, RST, P0–P7

10 pF

V+ = +1.71V, I

SINK

= 5mA (QSOP) 90 180

V+ = +1.71V, I

SINK

= 5mA (TQFN) 90 230

V+ = +2.5V, I

SINK

= 10mA (QSOP)

210

V+ = +2.5V, I

SINK

= 10mA (TQFN)

260

V+ = +3.3V, I

SINK

= 15mA (QSOP)

230

V+ = +3.3V, I

SINK

= 15mA (TQFN)

280

V+ = +5V, I

SINK

= 20mA (QSOP)

250

Output Low Voltage
O8–O15, P0–P7

V

OL

V+ = +5V, I

SINK

= 20mA (TQFN)

300

mV

V+ = +1.71V, I

SOURCE

= 2mA

V+ = +2.5V, I

SOURCE

= 5mA

V+ = +3.3V, I

SOURCE

= 5mA

Output High Voltage
O8–O15

V

OH

V+ = +5V, I

SOURCE

= 10mA

mV

Output Low-Voltage SDA

I

SINK

= 6mA 250 mV

Output Low-Voltage INT

I

SINK

= 5mA

250 mV

Port Input Pullup Resistor R

PU

25 40 55 kΩ

1.71 5.50

V

OLSDA

V

OLINT

0.8 x V+

0.7 x V+

-0.2

V + - 250 V + - 30

V + - 360 V + - 70

V + - 260 V + - 100

V + - 360 V + - 120

0.2 x V+

0.3 x V+

110

110

130

130

140

140

130

MAX7325

I2C Port Expander with 8 Push-Pull

and 8 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)

PARAMETER

CONDITIONS

UNITS

Port Output Data Valid t

PPV

CL ≤ 100pF 4 µs

Port Input Setup Time t

PSU

CL ≤ 100pF 0 µs

Port Input Hold Time t

PH

CL ≤ 100pF 4 µs

INT Input Data Valid Time t

IV

CL ≤ 100pF 4 µs

INT Reset Delay Time from STOP

t

IP

CL ≤ 100pF 4 µs

INT Reset Delay Time from
Acknowledge

t

IR

CL ≤ 100pF 4 µs

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)

PARAMETER

CONDITIONS MIN

UNITS

Serial-Clock Frequency f

SCL

400 kHz

Bus Free Time Between a STOP
and a START Condition

t

BUF

1.3 µs

Hold Time (Repeated) START
Condition

0.6 µs

Repeated START Condition
Setup Time

0.6 µs

STOP Condition Setup Time

0.6 µs

Data Hold Time

(Note 2) 0.9 µs

Data Setup Time

100 ns

SCL Clock Low Period t

LOW

1.3 µs

SCL Clock High Period t

HIGH

0.7 µs

Rise Time of Both SDA and SCL
Signals, Receiving

t

R

(Notes 3, 4)

20 +

300 ns

Fall Time of Both SDA and SCL
Signals, Receiving

t

F

(Notes 3, 4)

20 +

300 ns

Fall Time of SDA Transmitting t

F,TX

(Notes 3, 4)

20 +

250 ns

Pulse Width of Spike Suppressed

t

SP

(Note 5)

ns

Capacitive Load for Each Bus
Line

C

b

(Note 3) 400 pF

RST Pulse Width t

W

500 ns

RST Rising to START Condition
Setup Time

t

RST

1µs

Note 1: All parameters are 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. I

SINK

≤ 6mA. tRand tFmeasured between 0.3 x V+ and 0.7 x V+.

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

SYMBOL

SYMBOL

t

HD, STA

t

SU, STA

t

SU, STO

t

HD, DAT

t

SU, DAT

MIN TYP MAX

TYP MAX

0.1C

b

0.1C

b

0.1C

b

50

MAX7325

I2C Port Expander with 8 Push-Pull
and 8 Open-Drain I/Os

4 _______________________________________________________________________________________

Typical Operating Characteristics

(TA = +25°C, unless otherwise noted.)

STANDBY CURRENT

vs. TEMPERATURE

TEMPERATURE (°C)

STANDBY CURRENT (µA)

MAX7325 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)

MAX7325 toc02

-40-25-105 203550658095110125

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)

MAX7325 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

OUTPUT VOLTAGE HIGH

vs. TEMPERATURE

TEMPERATURE (°C)

OUTPUT VOLTAGE HIGH (V)

MAX7325 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

NAME FUNCTION

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

3, 21

AD2, AD0

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).

4–11 1–8 P0–P7 Open-Drain I/O Ports

12 9 GND Ground

13–20 10–17 O8–O15 Output Ports. O8–O15 are push-pull outputs rated at 20mA.

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 ceramic capacitor of at least 0.047µF.

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

24, 18

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 MAX7319,
MAX7321, MAX7322, or MAX7323.

Functional Overview

The MAX7325 is a general-purpose port expander oper­ating from a +1.71V to +5.5V supply with eight push-pull
outputs and eight open-drain I/O ports. Each open-drain
output is rated to sink 20mA, and the entire device is
rated to sink 100mA into all ports combined. The outputs
drive loads connected to supplies up to +5.5V.

The MAX7325 is set to two of 32 I

2

C slave addresses
(see Tables 2 and 3) using the address select inputs
AD0 and AD2, and is accessed over an I2C serial inter­face up to 400kHz. The eight outputs and eight I/Os
have different slave addresses. The eight push-pull out­puts have the 101xxxx addresses and the eight inputs
have addresses with 110xxxx. The RST input clears the
serial interface in case of a bus lockup, terminating any
serial transaction to or from the MAX7325.

Configure any port as a logic input by setting the port
output logic-high (logic-high for an open-drain output is
high impedance). When the MAX7325 is read through
the serial interface, the actual logic levels at the ports
are read back.

MAX7325

I2C Port Expander with 8 Push-Pull

and 8 Open-Drain I/Os

_______________________________________________________________________________________ 5

PART

I2C

SLAVE

INPUTS

INPUT

INTERRUPT

MASK

OPEN­DRAIN

PUSH-

PULL

CONFIGURATION

16-PORT EXPANDERS

MAX7324

8 Yes — 8

8 input and 8 push-pull output versions:

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

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.

MAX7325

and

— Up to 8 8

8 I/O and 8 push-pull output versions:
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.

Table 1. MAX7319–MAX7329 Family Comparison

ADDRESS

OUTPUTS

OUTPUTS

101xxxx

110xxxx

Up to 8

MAX7325

I2C Port Expander with 8 Push-Pull
and 8 Open-Drain I/Os

6 _______________________________________________________________________________________

PART

I2C

SLAVE

INPUTS

INPUT

INTERRUPT

MASK

OPEN­DRAIN

PUSH-

PULL

CONFIGURATION

MAX7326

4 Yes — 12

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

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.

MAX7327

and

— Up to 4 12

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.

8-PORT EXPANDERS

MAX7319

8 Yes — —

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

MAX7320

—— — 8

Output-only versions:
8 push-pull outputs with selectable power-up default
levels.

MAX7321

— Up to 8 —

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

MAX7322

4 Yes — 4

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.

Table 1. MAX7319–MAX7329 Family Comparison (continued)

ADDRESS

101xxxx

110xxxx

Up to 4

OUTPUTS

OUTPUTS

110xxxx

101xxxx

110xxxx Up to 8

110xxxx