We are considering using the TMUX1109 for multiplexing various digital interface signals including I2C, SPI bus, I2S digital audio, SWD (for programming ARM microcontroller) and UART at 1.8V supply. Is this multiplexer compatible with these digital interfaces? The I2C bus will require pull-up resistors, while SWD will have pull-up and pull-down resistors.
Hi Alula,
The TMUX1109 should be able to support any protocol that utilizes two wire communication (I2C, SWD,UART), and as long as the I/O signals comply with the typical 135 MHz BW limitation. The TMUX1109 also supports 1.8V supply voltage, and supports bidirectional signal pathing.
From TMUX1109 Datasheet:
I say for two wire communication protocols because I feel it would be difficult to time a 4-wire protocol (such as SPI) for a 4:1, 2 channel mux such as the TMUX1109.
Here is my example:
For communication protocol that uses 3 or more wires (I2S digital audio, SPI), I would suggest TMUX1574. This product is a 2:1 (SPDT), 4 channel analog switch which has sufficient I/O BW (2 GHz), your 1.8V supply voltage requirement, and bidirectional signal pathing.
Using this switch will simplify the above example I just gave to this:
Now you won’t have to mess with address bits as much to switch between signals. This example would use more wires however.
In terms of pull-up/pull-down resistors, this should be able to work on the outputs of both TMUX1109 and TMUX1574. You might need an external switch to turn off/on the PU/PD resistor when switching between different communication protocols.
Regards,
Tyler
