TS5A23166: What is the difference between TS5A23166DCUR and TS5A21366DCUR?

Hey Adam,

These devices are pretty similar but there are slight spec differences in CON and leakage specs. They also share the same pinout and the packages are the same as well. The biggest differentiation here will come in the logic levels. The TS5A23166 looks to be using some TTL logic compatible levels: 

While the TS5A21366 has the upgraded feature of being 1.8V logic compatible:

For more information on the VIH, VIL levels and 1.8V logic compatibility we have a couple good resources i'm linking below as well:

[FAQ] What are the VIH & VIL Levels of an Analog Switch / Multiplexer

Application Brief : 1.8 V Logic for Muxes and Signal Switches

Hope this helps!

Thanks,
Rami