CAT9555
16-bit I2C and SMBus I/O Port with Interrupt
FEATURES
DESCRIPTION
■ 400kHz I2C bus compatible*
■ 2.3V to 5.5V operation
The CAT9555 is a CMOS device that provides 16-bit
parallel input/output port expansion for I2C and SMBus
compatible applications. These I/O expanders provide
a simple solution in applications where additional I/Os
are needed: sensors, power switches, LEDs,
pushbuttons, and fans.
■ Low stand-by current
■ 5V tolerant I/Os
■ 16 I/O pins that default to inputs at power-up
■ High drive capability
The CAT9555 consists of two 8-bit Configuration ports
(input or output), Input, Output and Polarity inversion
registers,andanI2C/SMBus-compatibleserialinterface.
■ Individual I/O configuration
■ Polarity inversion register
■ Active low interrupt output
■ Internal power-on reset
Any of the sixteen I/Os can be configured as an input or
outputbywritingtotheconfigurationregister.Thesystem
master can invert the CAT9555 input data by writing to
the active-high polarity inversion register.
■ No glitch on power-up
■ Noise filter on SDA/SCL inputs
■ Cascadable up to 8 devices
■ Industrial temperature range
The CAT9555 features an active low interrupt output
which indicates to the system master that an input state
has changed.
The three address input pins provide the device's
extended addressing capability and allow up to eight
devices to share the same bus. The fixed part of the I2C
slave address is the same as the CAT9554, allowing up
to eight of these devices in any combination to be
connected on the same bus.
■ RoHS-compliant 24-lead SOIC and TSSOP, and
24-pad TQFN (4 x 4 mm) packages
APPLICATIONS
■ White goods (dishwashers, washing machines)
■ Handheld devices (cell phones, PDAs, digital
cameras)
■ Data Communications (routers, hubs and
For Ordering Information details, see page 16.
servers)
BLOCK DIAGRAM
A0
A1
A2
I/O1.0
I/O1.1
I/O1.2
INPUT/
8-BIT
I/O1.3
I/O1.4
I/O1.5
I/O1.6
I/O1.7
OUTPUT
PORTS
WRITE pulse
READ pulse
2
I
C/SMBUS
CONTROL
I/O0.0
I/O0.1
I/O0.2
I/O0.3
I/O0.4
I/O0.5
I/O0.6
I/O0.7
SCL
INPUT
FILTER
INPUT/
OUTPUT
PORTS
8-BIT
SDA
WRITE pulse
READ pulse
V
CC
V
INT
POWER-ON
RESET
V
CC
LP FILTER
INT
~
NOTE: ALL I/Os ARE SET TO INPUTS AT RESET
2
* Catalyst Semiconductor is licensed by Philips Corporation to carry the I C Bus Protocol.
© 2007 by Catalyst Semiconductor, Inc.
Characteristics subject to change without notice
Doc. No. 8551, Rev. E
1