We present an equivalent circuit model for a silicon microring modulator (MRM), aiming to accurately describe its behavior in high-speed modulation. The model consists of two parts: the first part accounts for electrical parasitics arising from PN phase shifters and pads, while the second part represents the RLC circuit responsible for capturing optical dynamics of MRMs. Model parameters were derived through curve fitting, utilizing Si MRM characterization data. At data rates of 80Gb/s and 106Gb/s, simulated eye diagrams align perfectly with measured eye diagrams. The equivalent circuit model can be effectively used for electronics and photonics co-design. © 2023 SPIE.