Abstract
The designs of resistive RAM (ReRAM) macros are limited by 1) a small sensing margin, limited read-VDDmin, and slow read access time (T AC ) caused by a high cell-resistance and small cell-resistance-ratio (R-ratio) and 2) poor power integrity and increased energy waste attributable to a large SET dc-current (I DC-SET ) resulting from the wide distribution of write (SET)-times (T SET ). This study proposes a swing-sample-and-couple (SSC) voltage-mode sense amplifier (VSA) to enable an approximately 1.8+ x greater sensing margin for lower VDDmin and a 1.7+x faster read speed across a wide VDD range, compared with conventional VSAs. A 4T self-boost-write-termination (SBWT) scheme is proposed to cut off the I DC-SET of devices with a rapid T SET . The SBWT scheme reduces 99+% of the I DC-SET with an area penalty below 0.5%. A fabricated 512 row 28 nm 1 Mb ReRAM macro achieved T AC =404 ns when VDD=0.27 V and confirmed the I DC-SET cutoff by the SBWT.