High speed, high stability and low power sensing amplifier for MTJ/CMOS hybrid logic circuits

Densely embedding Magnetic Tunnel Junctions (MTJ) in CMOS logic circuits is considered as one potentially powerful solution to bring non volatility, instant on/off and low standby power in today's programmable logic circuits, in order to overcome major drawbacks while preserving high operation speed. A critical issue in this process is the integration of MTJ electric signal to CMOS electronics, in particular the requirement of "zero" read/write error for logic applications. In this paper, we propose a new sense amplifier circuit, called Pre-Charge Sense Amplifier (PCSA). This circuit, comprising 7 CMOS transistors at minimum size, is able to read the magnetic configuration of a pair of magnetic tunnel junctions with opposite configurations at high speed (about 200 ps), with very low power and error rate compared to previously proposed solutions. Simulations using a ST Microelectronics 90 nm design kit and a compact model of MTJ demonstrate the performances of PCSA.