Depending on your simulation environment, you can obtain the necessary .lib or .sub files from these reputable sources:
: Open the library file in LTspice, right-click the .SUBCKT CD4051 line, and select "Create Symbol" . This creates a functional component box with the correct pin mappings. cd4051 spice model link
: Sites like DatasheetArchive aggregate various older models, though these should be tested against the physical CD4051 datasheet to ensure the RONcap R sub cap O cap N end-sub (On-Resistance) matches your specific voltage range. How to Use a CD4051 Subcircuit in LTspice Depending on your simulation environment, you can obtain