8-channel 1.65- to 5.5-V I2C/SMBus switch with reset & voltage translation | DGS | 24 | -40 to 85

The TCA9548A device has eight bidirectional

translating switches that can be controlled through the I2C 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 I2C target 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 controller 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 I2C/SMBus state machine. Asserting

RESET causes the same reset and initialization to occur

without powering down the part. This allows recovery if one of the downstream

I2C 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 1.8V, 2.5V or 3.3V parts can communicate with 5V

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 5V tolerant.