TCA9548APWR

The TCA9548A device has eight bidirectional
translating switches that can be controlled through
the I
2C bus. The SCL/SDA upstream pair fans out to
eight downstream pairs, or channels. Any individual
SCn/SDn channel or combination of channels can be
selected, determined by the contents of the
programmable control register. These downstream
channels can be used to resolve I
2C slave address
conflicts. For example, if eight identical digital
temperature sensors are needed in the application,
one sensor can be connected at each channel: 0-7.
The system master can reset the TCA9548A in the
event of a time-out or other improper operation by
asserting a low in the RESET input. Similarly, the
power-on reset deselects all channels and initializes
the I
2C/SMBus state machine. Asserting RESET
causes the same reset and initialization to occur
without powering down the part. This allows recovery
should one of the downstream I
2C buses get stuck in
a low state.
The pass gates of the switches are constructed so
that the VCC pin can be used to limit the maximum
high voltage, which is passed by the TCA9548A.
Limiting the maximum high voltage allows the use of
different bus voltages on each pair, so that 1.8-V, 2.5-
V or 3.3-V parts can communicate with 5-V parts,
without any additional protection. External pullup
resistors pull the bus up to the desired voltage level
for each channel. All I/O pins are 5-V tolerant.