Want to get a better feel for how a precision SAR ADC performs in a signal chain design before you get your pcb design manufactured?  Tired of having to spend time and re-design effort to get your precision data acquisition design just right? Then give our new AD7960 SAR LTspice model a try and tell us about your experience in the comments. The models, two test benches and a user guide are attached to this blog in a zip file and may be downloaded below.

The pdf user guide contained in the zip file will lead you through the model, as well as demonstrate how to run the two example test benches and the results you should expect. Please note this is a BETA model. As this is still a work in progress, you may find some bugs but that’s what the comment section is for.

The first test bench simulates a full scale input step to the ADC and driver circuit, similar to what you might see if you were multiplexing many channels into one ADC. The simulation results are shown along with wave forms of the input settling below.

The second test bench shows the AC performance of the ADC and drive circuit and how to perform an FFT in LTspice. The input to the driver circuit and ADC in this case is a 14.6Khz differential sine wave and we perform 1024 conversions in order to do a 1024 point FFT. The FFT result is shown below.

Feel free to give the model and test benches a try as well as make changes to simulate different scenarios e.g. different driver amplifiers, RC combinations etc. As stated above the model is a BETA model. We welcome any and all feedback regarding what you like, don’t like or what you would like to see added. Please comment below this blog to share your thoughts on our new LTspice model for the AD7960 Precision SAR ADC.