Six-input lookup table circuit with 62% fewer transistors using nonvolatile logic-in-memory architecture with series/parallel-connected magnetic tunnel junctions

Abstract

A compact 6-input lookup table (LUT) circuit using nonvolatile logic-in-memory (LIM) architecture with series/parallel-connected magnetic tunnel junction (MTJ) devices is proposed for a standby-power-free field-programmable gate array. Series/parallel connections of MTJ devices make it possible not only to reduce the effect of resistance variation, but also to enhance the programmability of resistance values, which achieves a sufficient sensing margin even when process variation is serious in the recent nanometer-scaled VLSI. Moreover, the additional MTJ devices do not increase the effective chip area because the configuration circuit using MTJ devices is simplified and these devices are stacked over the CMOS plane. As a result, the transistor counts of the proposed circuit are reduced by 62% in comparison with those of a conventional nonvolatile LUT circuit where CMOS-only-based volatile static random access memory cell circuits are replaced by MTJ-based nonvolatile ones.

Silicon spintronics: Progress and challenges

“…Several MTJ/MOS hybrid logic-in memory circuits have so far been proposed [167]. A six-input lookup table circuit using non-volatile logic in memory architecture is a standby-power free field-programmable array which also allows to reduce the transistor count by 62% [168].…”

Challenge of Nonvolatile Logic LSI Using MTJ-Based Logic-in-Memory Architecture

“…operation of the multi-input LUT circuit, we insert "redundant" MTJ devices to adjust the operating point of the LUT circuit. Figure 8 shows a design example of the multi-input nonvolatile LUT circuit, where both twice number of MTJs and three additional MTJs are inserted into the LUT-selection tree and the LUTreference tree, respectively [7,8]. Figure 9 summarizes the comparison of multiinput LUT circuits.…”

“…3b, it would be possible to improve the performance of the nonvolatile logic LSI. In the following description, some concrete design examples using MTJ-based nonvolatile NV-LIM architecture such as nonvolatile field programmable gate array (FPGA) [6][7][8][9][10][11][12][13][14], nonvolatile ternary content-addressable memory (TCAM) [15][16][17][18][19][20][21][22], and nonvolatile randomaccess logic-LSI unit (MCU) [23,24] are demonstrated and their usefulness is discussed. Power : greatly reduced, Delay : shorter Field programmable gate array (FPGA) is a key device to quickly realize prototyping systems, where their specification and function are directly programmable by users, while power consumption as well as hardware cost is a serious problem in expanding application fields of FPGAs, especially in the field of mobile and portable applications [25].…”

Design of Look up Table for Emerging Non Volatile Memories in FRAM

“…In this application average power consumption is a critical design concern.SRAM-based fieldprogrammable gate arrays (FPGAs) have been widely used during the last decades. However, the volatility of SRAM has limited FPGAs in applications where high security and instant power-on are required [3,9]. The problem can be solved by introducing nonvolatile memory (NVM) as the configuration bit.…”