Low power designs are very critical to mobile and IoT applications. M31 low power solution is comprehensive for low power designs. It includes the green memory, low VCC_MIN memory, low power cell library, low VCC_MIN PLL and low power interface IP like USB 2.0 and USB 1.1. M31 green memory provides low power modes including standby, nap, retention, and power shutdown modes. The dual rail architecture is also built in the green memory for dynamic frequency and voltage scaling. M31 low VCC_MIN memory supports low voltage operation to reduce leakage and dynamic power directly. To achieve low power SoC design, M31 low power cell library is the critical component. Not only low power optimized cells but also power management kit are included.