A 22-nm 32-Mb Embedded STT-MRAM Macro Achieving 5.9-ns Random Read Access and 7.4-MB/s Write Throughput at up to 150 °C

• Published in: IEEE journal of solid-state circuits Vol. 59; no. 4; pp. 1283 - 1292
• Main Authors: Shimoi, Takahiro, Matsubara, Ken, Saito, Tomoya, Ogawa, Tomoya, Taito, Yasuhiko, Kaneda, Yoshinobu, Izuna, Masayuki, Takeda, Koichi, Mitani, Hidenori, Ito, Takashi, Kono, Takashi
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.04.2024; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Clamps; Electric potential; Embedded STT-MRAM (eMRAM); fast random read operation; high write throughput; high-end microcontroller unit (MCU); Magnetic tunneling; Magnetoresistivity; one-time programmable (OTP); Random access memory; Security; Sense amplifiers; spin transfer torque-MRAM (STT-MRAM); Throughput; Timing; Transistors; Voltage
• ISSN: 0018-9200; 1558-173X
• DOI: 10.1109/JSSC.2023.3314822

This article presents a high-precision sense amplifier technique, a fast write scheme, and a one-time-programmable (OTP) memory cell read technique applied to a 22-nm 32-Mb embedded STT-MRAM (eMRAM) macro for high-end microcontroller units (MCUs). A boosted cross-coupled sense amplifier (BCC-SA) achieves 5.1- and 5.9-ns random read access at 125 °C and 150 °C, respectively. A variable parallel bit write (VPBW) with a fast voltage setup (VPBW-FVS) scheme and write voltage always on (WVAO) mode enable 7.4-MB/s write throughput and 73% write energy reduction. A stabilization of operating conditions with variable current (SOC-VC) technique allows a sense amplifier to be shared with both embedded magnetoresistive random access memory (MRAM)-based OTP and MRAM cell read modes.