When working with AMS simulators, simulation speed can vary significantly depending on whether you use the .dc or .step commands in your simulation script. Understanding the distinction between these two commands is key to optimizing your simulation workflow.
.dc and .step Work.dc Command:.dc command performs a single simulation run across all model parameter values. This means the simulator evaluates all parameter variations in one continuous process, without restarting or reinitializing the design. This streamlined approach is generally faster because it avoids repetitive setup tasks..step Command:.step command executes a separate simulation run for each parameter value. For every new parameter step, the simulator must reinitialize and elaborate the design. This process of elaboration involves preparing and configuring the entire model for simulation, which can significantly increase the overall simulation time.Elaboration is a crucial but time-intensive process in AMS simulations, particularly when using VHDL-AMS models in your design. Each simulation run under the .step command requires full elaboration of the design to accommodate the specific parameter values. As a result, a DC sweep must use the .step command when VHDL-AMS models are involved, leading to slower simulations compared to using .dc.
.dc command for faster simulations when all parameter values can be handled in a single run..step command is required, even though it is slower.By understanding these differences, you can make informed decisions about which command to use based on your simulation needs and the models in your design.