Multilevel sense amplifier sensing for phase change memory

Abstract

In recent years, there has been a very rapid advancement in the area of phase-changing materials, due to which there has been a substantial improvement in Phase-change memories (PCM) and its technology. Due to scaling limitations in flash memories, PCM seems to be the most promising alternative among the various emerging Non-Volatile Memories (NVM). Their ability to store more than two levels of data can be exploited to store multiple bits within a single PCM cell. In this work, we have defined a sensing scheme for reading the data stored in the PCM cell, which has the capability of storing 2bits/cell. This sensing architecture has the capability of sensing both the bits in one read cycle, also called parallel sensing. The access time of the proposed scheme is 12.04 nS with a targeted nominal current offset of 1uA. The area of the circuit is 327um2, and the average power per reading is 106uW