Ultra-Efficient Nonvolatile Approximate Full-Adder with Spin-Hall-Assisted MTJ Cells for In-Memory Computing Applications

Approximate computing aims to reduce the power consumption and design complexity of digital systems with the cost of a tolerable error. In this project, two ultra-efficient magnetic approximate full adders are presented for computing-in-memory applications. The proposed ultra-efficient full adder blocks are coupled with a memory cell based on Magnetic Tunnel Junction (MTJ) to allow for non-volatility. Therefore, they can be power-gated when required. Both the proposed full adders have simple designs and are energy efficient. Instead of introducing dedicated write-driver and read circuits, the restorer latch inverters are utilized to contribute to the read and write operations, which results in a lower complexity. The peripheral circuitries are designed based on the Gate All-Around Carbon NanoTube Field-Effect Transistor (GAA-CNTFET).