I would recommend either the ADG712 or the ADG812 as an alternative to the FST3125MX. They are both 4 x SPST switches with the ADG812 having the lowest Ron and the ADG712 with a larger signal bandwidth.
Is it OK to tie NC pin (pin #4) to ground for ADG811YRUZ and ADG812YRUZ? Is there an internal bond?
Thank you for considering my question.
In the Absolute Maximum Ratings (Table 3) of the data sheet, it shows that the maximum continuous current that S or D can handle is 30mA at 25C. At 70C, the maximum continuous current would be less again.
So the answer would be that you would…