TS3A44159: TS3A44159 IBIS model for cascading switches in SPI mux application

Patrick, 

If you look at Ti.com TS3A44159 product folder under the Tools and Software tab and then model menu bar you can see that there are not any models for this device.  What are you looking to simulate with device?  What are you connecting to this switch?  Maybe I can give you guidance on how the device will perform instead of using a simulation.   

There is a similar TMUX1574 device that does have IBIS and s-parameter models available. 

Thank you, 

Adam

Patrick,

What type of guidance would you like on the diagram?

It looks like you have a switch matrix to connect various parts of the system with cascaded switches. Each time a switch is cascaded there will be an additional set of on-state resistance and on-state capacitance in the signal path.

Any reason why you are using two different types of switches SN74CB3Q3257 and TS3A44159?

The new TMUX1574 device was specifically designed for SPI mux applications and has s-parameter models so you can see the effect of cascaded switches.

Thank you,
Adam

Patrick,

It looks like your worst case path is through 4x switches.  If you use the SN74CB3Q3257 with 8 ohm on-state resistance and 7pF on-state capacitance there will be at least 24 ohm resistance and 28pF capacitance in your signal chain due to the switches.  If you driver can support these loads at the frequency you want to operate including the PCB and receiver loads the SN74CB3Q3257 could work. 

The TS3A44159 has on state capacitance of 164pF which would have 656pF capacitance when you cascade 4x switches in series. I'm not sure you driver could handle this load but if it can you can use it.

We would always recommend using the newest TMUX1574 products because they will be on the best technology we can offer today. 

Thank you,

Adam