Variation-tolerant Non-volatile Ternary Content Addressable Memory with Magnetic Tunnel Junction

Abstract

A magnetic tunnel junction (MTJ) based ternary content addressable memory (TCAM) is proposed which provides non-volatility. A unit cell of the TCAM has two MTJ's and 4.875 transistors, which allows the realization of TCAM in a small area. The equivalent resistance of parallel connected multiple unit cells is compared with the equivalent resistance of parallel connected multiple reference resistance, which provides the averaging effect of the variations of device characteristics. This averaging effect renders the proposed TCAM to be variation-tolerant. Using 65-nm CMOS model parameters, the operation of the proposed TCAM has been evaluated including the Monte-Carlo simulated variations of the device characteristics, the supply voltage variation, and the temperature variation. With the tunneling magnetoresistance ratio (TMR) of 1.5 and all the variations being included, the error probability of the search operation is found to be smaller than 0.033-%.