In modern DRAM design, IR-drop has emerged as a critical factor leading to operation failures, primarily due to reduced metal resources and increased supply current demands. Consequently, estimating and addressing IR-drop throughout the DRAM design process has become a crucial sign-off consideration. The proposed comprehensive methodology for the power delivery network (PDN) includes accurate and efficient estimation at two key stages: early in the design process (Early PDN) and during post-physical design sign-off validation (Iterative PDN). The Early PDN approach employs simplified modeling to achieve reasonable accuracy, serving as a guideline for the initial PDN design. Subsequently, the Iterative PDN method provides a fast yet detailed analysis of the entire DRAM, including the PDN, ensuring it is suitable for final sign-off. By applying this methodology, PDN behavior can be effectively predicted and optimized, ensuring robustness. This enhances the reliability and performance of DRAM designs.