SN3257-Q1: Does this device support a daisy-chain topology?

Yes, this is possible.

2× TMUX1309 would be cheaper. What frequency do you need?

Hi Leo,

The short answer is yes - this is a possible configuration of the device.

The long answer is that it depends on the SPI frequency that you are running at. Putting multiplexers in parallel like this is going to increase the effective capacitance of the switch block which could degrade bandwidth; however it may not be an issue depending on what frequency you are trying to achieve with this SPI implementation. 

Please let me know the frequency you are working at and  I will verify if this is okay or not.

Best,

Parker Dodson

thanks Parker Dodson，the frequency of spi is 10Mhz

thanks，10MHz