An ultra low voltage subthreshold standard cell based memories for IoT applications

In this paper, we have designed an ultra low voltage standard cell based memory (SCM) in the subthreshold domain. The SCM has been synthesized, placed and routed based on an ultra low voltage full custom standard cell library using 130 nm process technology, functional for subthreshold supply voltages as low as 140 mV, which is well below the supply voltages reported in the previous works of SCMs. This SCM has been designed based on the standard D-latch which holds data at a supply voltage as low as 170 mV. The designed SCM is functional for a temperature range of 27-50 °C applicable for implantable biomedical systems requiring small memory capacity. According to the simulations from the extracted netlist, the energy per bit access at Vdd=200 mV and 333 kHz frequency, suitable for many loT applications, is 1.54 fJ.