In the paper, "Device noise simulation of Delta Sigma Modulators",

It says that an ideal S/H is used to close the loop for noise simulation.

I tried to use the model in "Simulating switched-capacitor filters with SpectreRF ".

The model, however, is a self-clocked model.

Thus, I couldn't use it for closing the loop which requires an externally clocked S/H.

Does anyone know where I can get an appropriate S/H  model for closing the differential loop?

Thank you in advance.