Hi Adam,
I have a question regrading power supply for TS3A27518E. 3.3V is the power system. Is there any problem to supply switch with 3.3V while the logic level of the digital signal interface is 1.8V? In the datasheet, VI for digital input signal will support from 0-VCC. For our case, I need VCC = 3.3V for the 1.8V digital signals (JTAG, UART, SPI or MDIO) passing. if you need schematic to review, please let me know.