A Highly Reliable, Dynamic Logic-Based Hybrid MTJ/CMOS Magnetic Full Adder for High-Performance and Low-Power Application

• Published in: IEEE transactions on magnetics 2022-05, Vol.58 (5), p.1-8
• Main Authors: Shukla, Pratiksha, Kumar, Pramod, Misra, Prasanna Kumar
• Format: Article
• Language: English
• Subjects: Adders; Adding circuits; Charge injection; Circuit reliability; clock feedthrough; Clocks; CMOS; Electric potential; Errors; high-performance; Logic gates; Magnetic anisotropy; magnetic full adder (MFA); magnetic tunnel junction (MTJ); Magnetic tunneling; Magnetism; Perpendicular magnetic anisotropy; Power consumption; Semiconductor devices; Transistors; Tunnel junctions; Voltage
• ISSN: 0018-9464; 1941-0069
• DOI: 10.1109/TMAG.2022.3159823

At deep sub-micrometer technology, CMOS circuits suffer from high leakage and have reliability issues due to process variation. Hybrid magnetic tunnel junction (MTJ)/CMOS circuits have been proposed to overcome these challenges. MTJs have zero standby power and are compatible with CMOS technology. In this article, a dynamic logic-based hybrid MTJ/CMOS magnetic full adder (MFA) has been proposed, which eliminates the error voltage appearing on output due to charge injection and clock feedthrough phenomenon, thereby enhancing the performance of MFA and making it more reliable. This effect is induced by the pMOS transistor, which is used as a switch to precharge the output nodes. The proposed MFA uses two dummy transistors, whose drain and source terminals are shorted to make them act as MOS capacitors, to absorb the error voltage introduced by the switch pMOS transistor due to charge injection and clock feedthrough, when turned OFF. Eliminating the error induced due to charge injection and clock feedthrough makes the amplification process faster and reduces the dynamic power consumption. Results are verified by performing transient and Monte Carlo simulations using cadence virtuoso with UMC 40 nm CMOS technology kit and compact model of perpendicular magnetic anisotropy (PMA) MTJ, which validates that the proposed MFA is highly reliable as it provides the error-free output and imparts better power-delay product (PDP) compared to previously proposed MFA.