Datasheet

PCA9538A All information provided in this document is subject to legal disclaimers. © NXP B.V. 2012. All rights reserved.
Product data sheet Rev. 1 — 28 September 2012 11 of 37
NXP Semiconductors
PCA9538A
Low-voltage 8-bit I
2
C-bus I/O port with interrupt and reset
8. Application design-in information
Device address is 1110 000x for this example.
P0, P2, P3 configured as outputs.
P1, P4, P5 configured as inputs.
P6, P7 are not used and need 100 k pull-up resistors to protect them from floating or the internal pull-up or pull-down
selected.
(1) Resistors are required for inputs (on P port) that may float. If a driver to an input will never let the input float, a resistor is not
needed. Outputs (in the P port) do not need pull-up resistors.
Fig 11. Typical application
PCA9538A
P0
P1
SCL
SDA
V
DD
(3.3 V)
MASTER
CONTROLLER
SCL
SDA
INT
P2
V
DD
V
DD
V
SS
INT
10 kΩ
SUB-SYSTEM 1
(e.g., temp sensor)
P3
INT
SUB-SYSTEM 2
(e.g., counter)
RESET
controlled
switch
(e.g., CBT device)
A
B
enable
V
SS
002aah420
10 kΩ10 kΩ 2 kΩ
100 kΩ
(× 3)
(1)
RESET RESET
10 kΩ
P4
P5
P6
P7
A1
A0
SUB-SYSTEM 3
(e.g., alarm system)
ALARM
V
DD