Verilog-AMS-PAM

Abstract

Current Verilog-AMS system level modeling does not capture the physical design (layout) information of the target design as it is meant to be fast behavioral simulation only. Thus, the results of behavioral simulation can be very inaccurate. In this paper a paradigm shift of the current trend is presented that integrates layout level information (with full parasitics) in Verilog-AMS through polynomial metamodels such that system-level simulation of a mixed-signal circuit/system is realistic and as accurate as the true parasitic netlist simulation. As a specific case study, a voltage-controlled oscillator (VCO) Verilog-AMS behavioral model and design flow are proposed to assist fast PLL design exploration. Based on a quadratic polynomial metamodel, the PLL simulation achieves approximately a 10X speedup compared to the layout extracted, parasitic netlist. The simulations using this behavioral model attain high accuracy. The observed error for the simulated lock time and average power consumption are 0.7% and 3%, respectively. This behavioral metamodel approach bridges the gap between layout accurate but fast simulation and design space exploration.