TMUX1209: For UART to Slave

Hey Daviel,

The parameters you'll be interested in for UART applications will be mainly the On-capacitance, Bandwidth, voltage range, and of course the configuration.

A digital signal is passing through so minimized added capacitance will allow for a more robust signal passthrough to limit any data corruption. UART is peer to peer so the load capacitance shouldn't be too high anyways but it's always a good measure to minimize the capacitance in case your setup does have a larger load.

This goes hand in hand with the BW, since typically minimizing the capacitance will increase bandwidth. While the bandwidth is important, most our devices have more than enough bandwidth to handle UART signal rates. Typically we recommend to have 1.5 - 3 times the bit rate as the bandwidth. I haven't heard of much successful UART communication in the Mbs and even our lowest BW muxes can support up to 15-20MHz (UART is a serial communication where 1bps = 1Hz). So in essence this isn't much of an interested when looking for a UART mux from TI's portfolio.

You'll also want to check the voltage range of the signal being passed through the mux and make sure the mux can handle it. shifting sometimes is done between these UARTs and RS232s, where the RS232 voltage may be higher than the UART. Which is fine as long as the actual signal passing through the mux can be handled by the mux. 

Lastly, the configuration matters. Typically UART is a 2 wire peer to peer interface. There is 4 wire options though. but assuming you have 2 wire and 3 slaves you'll want a 2 channel device with atleast 3:1 configuration. So the TMUX1209 would be a good fit here, assuming you're working with a 5V UART system. 

Thanks,
Rami