Alternatively, here's a I've used for basic functionality (no Ron variation):
Hi everyone,
Looking for / Sharing a working SPICE model for CD4051 (8:1 analog multiplexer) cd4051 spice model
* Simple CD4051 behavioral model (8:1 mux) .SUBCKT CD4051 COM A0 A2 A1 INH VEE VSS VDD * Add logic decoding + analog switch here .ENDS But this lacks analog accuracy. Alternatively, here's a I've used for basic functionality