Datasheet

APPLICATION INFORMATION
P0
P1
P2
P3
P4
P5
P6
P7
(5 V)
SCL
SDA
GND
SCL
SDA
PCA9557
A2
A1
A0
GND
INT
ALARM
Controlled Switch
(e.g., CBT Device)
ENABLE
1.8 kΩ 1.8 kΩ
620 Ω
A
B
2 kΩ
10 kΩ
100 k ( 5)XΩ
RESET
V
CC
V
CC
V
CC
GND
RESET
RESET
Subsystem 1
2 kΩ
Subsystem 2
(e.g., Counter)
Subsystem 3
(e.g., Alarm System)
Master
Controller
PCA9557
SCPS133I – DECEMBER 2005 – REVISED JUNE 2008 .................................................................................................................................................... www.ti.com
Figure 14 shows an application in which the PCA9557 can be used.
A. Device address is configured as 0011100 for this example.
B. P1, P4, and P5 are configured as inputs.
C. P0, P2, and P3 are configured as outputs.
D. P6 and P7 are not used and must be configured as outputs.
Figure 14. Typical Application
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