A 3T1R Nonvolatile TCAM Using MLC ReRAM for Frequent-Off Instant-On Filters in IoT and Big-Data Processing

Existing nonvolatile ternary content-addressablememory (nvTCAM) suffers from limited word-length (WDL), large write-energy (EW) and search-energy (ES), and large cell area (A). This paper develops a 3T1R nvTCAM cell using a single multiple-level cell (MLC)-resistive RAM (ReRAM) device to achieve longWDL, lower EW and ES, and reduced cell area. Two peripheral control schemes were developed, dual-replica-row selftimed and invalid-entry power consumption suppression (IEPCS), for the suppression of dc current in 3T1R nvTCAM cells in order to reduce ES. Two versions of the IEPCS scheme were developed (basic and charge-recycle-controlled) to alter the tradeoff between area overhead and power consumption in the updating of invalid-bits. A 128 b × 64 b 3T1R nvTCAM macro was fabricated using back-end-of-line ReRAM under 90-nm CMOS process. The fabricated MLC-based 3T1R nvTCAM macro achieved sub-1-ns search-delay and sub-6-ns wake-up time with supply voltage of 1 V and WDL = 64 b.