Low-Active-Energy and Low-Standby-Power Sub-threshold ROM for IoT Edge Sensing Systems

Key design goals of the sub-threshold ROM for IoT sensing systems are reducing active energy and standby power. A conventional ROM used NAND bit-lines with a source-line scheme to conquer noise issues and a code-inversion scheme to improve performance. This work adopts OAI bit-lines to increase the I _on /I _off ratio for lowering the Vmin. It reduces energy and power consumption by removing source drivers and code-inversion circuitry. The proposed 256-Kb 90nm OAI-ROM operates at 0.22V and achieves 62% and 70% reduction in active energy and standby power, respectively, compared to the NAND-ROM.