TCA9543A_15 Datasheet, PDF (17/32 Pages) Texas Instruments – TCA9543A Low Voltage 2-Channel I2C Bus Switch With Interrupt Logic And Reset

www.ti.com
10 Application and Implementation
TCA9543A
SCPS206A – MARCH 2014 – REVISED FEBRUARY 2015
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.
10.1 Application Information
Applications of the TCA9543A will contain an I²C (or SMBus) master device and up to two I²C slave devices. The
downstream channels are ideally used to resolve I²C slave address conflicts. For example, if two identical digital
temperature sensors are needed in the application, one sensor can be connected at each channel: 0 and 1.
When the temperature at a specific location needs to be read, the appropriate channel can be enabled and the
other channel switched off, the data can be retrieved, and the I²C master can move on and read the next
channel.
In an application where the I²C bus will contain many additional slave devices that do not result in I²C slave
address conflicts, these slave devices can be connected to any desired channel to distribute the total bus
capacitance across both channels. If both switches will be enabled simultaneously, additional design
requirements must be considered (See Design Requirements and Detailed Design Procedure).
10.2 Typical Application
A typical application of the TCA9543A will contain anywhere from 1 to 3 separate data pull-up voltages, V_DPUX ,
one for the master device (V_DPUM) and one for each of the selectable slave channels (V_DPU0 and V_DPU1). In the
event where the master device and both slave devices operate at the same voltage, then the pass voltage, V_pass
= V_DPUX. Once the maximum V_pass is known, V_cc can be selected easily using Figure 17. In an application where
voltage translation is necessary, additional design requirements must be considered (See Design Requirements).
Figure 16 shows an application in which the TCA9543A can be used.
V = 1.65 V to 5.5 V
DPUM
V = 3.3 V
CC
V = 1.65 V to 5.5 V
DPU0
SDA
SCL
I²C/SMBus
Master
13
SDA
12
SCL
11
INT
VCC
5
SD0
6
SC0
4
INT0
3
RESET _TCA9543A
Channel 0
V = 1.65 V to 5.5 V
DPU1
2
A1
1
A0
7
GND
9
SD1
10
SC1
8
INT1
Channel 1
Figure 16. Typical Application Schematic
10.2.1 Design Requirements
The pull-up resistors on the INT1-INT0 terminals in the application schematic are not required in all applications.
If the device generating the interrupt has an open-drain output structure or can be tri-stated, a pull-up resistor is
required. If the device generating the interrupt has a push-pull output structure and cannot be tri-stated, a pull-up
resistor is not required. The interrupt inputs should not be left floating in the application.
Copyright © 2014–2015, Texas Instruments Incorporated
Product Folder Links: TCA9543A
Submit Documentation Feedback
17