A 64 kb differential single-port 12T SRAM design with a bit-interleaving scheme for low-voltage operation in 32 nm SOI CMOS

Abstract

In this paper, a novel differential single-port 12T SRAM bitcell is presented. This bitcell uses a read buffer to eliminate read disturbance, improves the read stability and achieves read static noise margin equal to its hold static noise margin. Using a column-based select signal this bitcell provides a half-select free feature, facilitating a bit-interleaving structure to reduce multi-bit soft errors by conventional error correcting code techniques. By boosting the wordline and select signal voltage, this bitcell can read and write with no error at 300 mV while data can be held down to 250 mV in standby mode. Bitline leakage suppression in 12T bitcell allows more bitcells per bitline for high density SRAMs and provides faster read operation. This paper also introduces OpenRAM, an open-source memory compiler, that provides a platform for the generation, characterization, and verification of fabricable memory designs across various technologies, sizes, and configurations. Using OpenRAM, a 64 kb 12T SRAM macro is designed in IBM 32 nm SOI CMOS technology that operates down to 0.3 V with 50 MHz operating frequency while it functions at 0.9 V with 2.2 GHz operating frequency, as well.