The Electron-Ion Collider (EIC), to be constructed at Brookhaven National Laboratory (BNL), is a roughly 10 year project to design and construct a facility to collide high energy polarized electron beams with polarized proton and heavy ion beams at center of mass energies from 20 GeV to 140 GeV and luminosity up to 1034 cm-2s-1. The project is a partnership between BNL and the Thomas Jefferson National Accelerator Facility (Jefferson Lab, JLAB). The EIC Common Platform is an effort to design and implement a flexible, high-performance electronics platform for required Low Level Radio Frequency (LLRF), Timing, Machine Protection, Instrumentation, Power Supply, and general-purpose Accelerator Controls systems. The fundamental architecture of the Common Platform, centered on a Xilinx Zynq UltraScale+ MPSoC-based carrier board and a variety of function specific daughtercards, is an evolution of the LLRF Platform in use at the BNL Collider-Accelerator Department since 2009. The preliminary architectural design of the Common Platform and its application for LLRF controls is described.