TCA9534_16 Datasheet, PDF (23/38 Pages) Texas Instruments – Low Voltage 8-Bit I2C and SMBUS Low-Power I/O Expander with Interrupt Output and Configuration Registers

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9 Application and Implementation
TCA9534
SCPS197B – SEPTEMBER 2014 – REVISED NOVEMBER 2016
NOTE
Information in the following applications sections is not part of the TI component
specification, and TI does not warrant its accuracy or completeness. TI’s customers are
responsible for determining suitability of components for their purposes. Customers should
validate and test their design implementation to confirm system functionality.
9.1 Application Information
Figure 33 shows an application in which the TCA9534 can be used.
IO Expanders such as the TCA9534 are commonly used to obtain more general purpose I/Os. There are many
common uses for these additionial I/Os:
• Inputs from other ICs, such as interrupt signals from sensors
• Inputs from physical buttons (for detecting button presses)
• Outputs to control RESET or ENABLE signals on other ICs
• Outputs for controlling LEDs for visual feedback to a user
9.2 Typical Application
V_CC
V_CC
10 kΩ⁽¹⁾ 10 kΩ⁽¹⁾ 10 kΩ
SDA
Master
Controller
SCL
INT
GND
16
VCC
15
SDA
14
SCL
13 _INT
2 kΩ
4
P0
5
P1
P2 ⁶
7
P3
TCA9534
9
P4
10
P5
3
A2
2
A1
1 _A0
P6 11
P7 12
100 kΩ
(x 3)
Subsystem 1
(e.g., temperature sensor)
INT
RESET
Subsystem 2
(e.g., counter)
A
ENABLE
B
Controlled Device
(e.g., CBT device)
GND
8
ALARM
Subsystem 3
(e.g., alarm system)
V_CC
The SCL and SDA pins must be tied directly to VCC because if SCL and SDA are tied to an auxiliary power supply
that could be powered on while VCC is powered off, then the supply current, ICC, will increase as a result.
Device address is configured as 0100000 for this example.
P0, P2, and P3 are configured as outputs.
P1, P4, and P5 are configured as inputs.
P6 and P7 are not used and must be configured as outputs.
Figure 33. Application Schematic
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