[better] — Cd4051 Spice Model Link

These use controlled switches (voltage-controlled switches) and logic gates to simulate the CD4051. They simulate incredibly fast, prevent convergence errors, and accurately replicate the RONcap R sub cap O cap N end-sub (typically around depending on the supply voltage).

| Model Source | Simulator | File Link | Key Characteristics | Best For | | :--- | :--- | :--- | :--- | :--- | | | LTspice, Generic SPICE | SwitchAna.Lib | Community-created, includes CD4051, 4052, 4053. Includes CMOS transmission gate model. | Most analog simulations requiring accurate switch behavior. | | KiCad/ngspice Model | ngspice (KiCad, ngspice) | CD4051B._lib | User-created model for ngspice, tested with oscilloscope. | Mixed-signal simulations using open-source tools. | | Ideal Behavioral Switch | LTspice, ngspice, PSpice | N/A (built-in component) | Simple, fast, and functional. No model file needed. | Digital logic, control systems, keyboard matrix scanning. | | Custom Built Model | Any SPICE | N/A | Tailored to specific needs. | Niche or critical applications where other models fall short. |

Pin Pitfall: Unlike basic logic gates, the CD4051 features a VEEcap V sub cap E cap E end-sub pin (negative analog supply voltage) alongside VSScap V sub cap S cap S end-sub (digital ground) and VDDcap V sub cap D cap D end-sub

Before diving into simulation, it's helpful to briefly understand the device we're modeling. The CD4051 is a single-pole, 8-throw (SP8T) analog multiplexer/demultiplexer. It's part of the CD4000 series of CMOS logic. It allows you to route one of eight analog or digital input/output channels (I/O 0 through 7) to a common input/output pin (COM), using three binary address pins (A, B, and C). An INHIBIT (INH) pin is also available to disable all switches. cd4051 spice model link

) Inaccuracies: Generic SPICE switch models use fixed resistances. The real CD4051 RONcap R sub cap O cap N end-sub varies widely based on whether VDDcap V sub cap D cap D end-sub

: Right-click on the line of the subcircuit you want to use (e.g., the .SUBCKT 4051a line). From the context menu, select "Create Symbol". A dialog will appear asking, "Do you want to create a symbol for this?". Click "Yes". LTspice will automatically generate a basic rectangular symbol for the CD4051 with all its pins visible.

The search for a reliable, "universal" SPICE model link for the Includes CMOS transmission gate model

The absolute most reliable resource for a native .lib or .sub file for the 4000-series logic IC family is the LTspice Groups.io Technical Forum .

For many designers, the lack of a model is a dead end. But with the right resources, it’s merely a challenge to overcome. The key is knowing where to look and how to adapt community tools for your specific simulation needs.

: The on-resistance of the CD4051 varies significantly with supply. At RONcap R sub cap O cap N end-sub is typically hundreds of ohms, whereas at it drops to approximately | Mixed-signal simulations using open-source tools

Download cd4051.lib and cd4051.asy (symbol) from their zip archive.

Open the standard library file or create a dedicated CMOS.lib file, and paste the CD4051 subcircuit code at the bottom.