CAT9554, CAT9554A
8-bit I²C and SMBus I/O Port with Interrupt
FEATURES
400kHz I²C bus compatible (1)
DESCRIPTION
The CAT9554 and CAT9554A are CMOS devices that
provide 8-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.
2.3V to 5.5V operation
Low stand-by current
5V tolerant I/Os
8 I/O pins that default to inputs at power-up
High drive capability
The CAT9554/9554A consist of an input port register,
an output port register, a configuration register, a
polarity inversion register and an I²C/SMBus-
compatible serial interface.
Individual I/O configuration
Polarity inversion register
Active low interrupt output
Internal power-on reset
Any of the eight I/Os can be configured as an input or
output by writing to the configuration register. The
system master can invert the CAT9554/9554A 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 CAT9554/9554A features an active low interrupt
output which indicates to the system master that an
input state has changed.
RoHS-compliant 16-lead SOIC and TSSOP, and
16-pad TQFN (4 x 4mm) packages
The device’s extended addressing capability allows up
to 8 devices to share the same bus. The CAT9554A is
identical to the CAT9554 except the fixed part of the
I²C slave address is different. This allows up to 16 of
devices (eight CAT9554 and eight CAT9554A) to be
connected on the same bus.
APPLICATIONS
White goods (dishwashers, washing machines)
Handheld devices (cell phones, PDAs, digital
cameras)
Data Communications (routers, hubs and
servers)
For Ordering Information details, see page 15.
BLOCK DIAGRAM (1)
A0
A1
I/O
I/O
0
1
A2
I/O
I/O
I/O
2
3
4
8-BIT
SCL
INPUT/
OUTPUT
PORTS
INPUT
FILTER
2
I C/SMBUS
SDA
CONTROL
WRITE pulse
READ pulse
I/O
5
I/O
6
I/O
7
V
CC
POWER-ON
RESET
V
CC
V
SS
INT
LP FILTER
Notes:
(1) All I/Os are set to inputs at RESET.
© 2008 SCILLC. All rights reserved
Characteristics subject to change without notice
1
Doc. No. MD-9002, Rev. F