Dynamic Time-Domain Sensing Scheme for Spin-Orbit Torque MRAM

While spin-orbit torque magnetic random access memory (SOT-MRAM) have shown huge potential for building next-generation embedded memory due to their attractive characteristics, the read reliability remains one of the critical concerns precluding its further application. In this article, we propose a dynamic time-domain sensing (DTDS) scheme for SOT-MRAM, in which the conversion threshold voltage of voltage-to-time converter (VTC) can be dynamically changed according to the data stored in SOT-MRAM, so as to lengthen the time difference of the VTC output signals. The proposed DTDS scheme can achieve a significant improvement in sensing margin of time-domain, thereby increasing the read reliability and reducing bit error rate (BER). Applying it to a 128 <tex-math notation="LaTeX">×</tex-math> 128 SOT-MRAM using 28 nm CMOS technology, an average read BER of 2.84 <tex-math notation="LaTeX">×</tex-math> 10 <tex-math notation="LaTeX">⁻¹⁰</tex-math> is achieved, which is greatly reduced compared to the conventional time-domain sensing scheme.