8-channel I²C-bus multiplexer with reset

The NCA9547-Q100 is an octal bidirectional translating multiplexer controlled by the I²C-bus. The SCL/SDA upstream pair fans out to eight downstream pairs, or channels. Only one SCn/SDn channel can be selected at a time, determined by the contents of the programmable control register. The device powers up with Channel 0 connected, allowing immediate communication between the controller and downstream devices (targets) on that channel.

An active LOW reset input allows the NCA9547-Q100 to recover from a situation where one of the downstream I²C-buses is stuck in a LOW state. Pulling the RESET pin LOW resets the I²C-bus state machine causing all the channels to be deselected, except Channel 0 so that the controller can regain control of the bus.

The pass gates of the multiplexers are constructed such that the VCC pin can be used to limit the maximum high voltage which will be passed by the NCA9547-Q100. This 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 pull-up resistors pull the bus up to the desired voltage level for each channel. All I/O pins are 6 V tolerant.

This product has been qualified to the Automotive Electronics Council (AEC) standard Q100 (Grade 1) and is suitable for use in automotive applications.