Statistical Analysis and Comparison of 2T and 3T1D e-DRAM Minimum Energy Operation

Abstract

Abstract-Bio-medical wearable devices restricted to their smallcapacity embedded-battery require energy-efficiency of the highest order. However, minimum-energy point (MEP) at sub-threshold voltages is unattainable with SRAM memory, which fails to hold below 0.3V because of its vanishing noise margins. This paper examines minimum-energy operation of 2T and 3T1D e-DRAM gain cells as an alternative to SRAM at 32nm technology node with different design points: up-sizing transistors, using high-Vth transistors, read/write wordline assists and temperature. First, the e-DRAM cells are evaluated without considering any process variations. The design-space is explored by creating a kriging meta-model to reduce the number of simulations. A full-factorial statistical analysis of e-DRAM cells is performed in presence of threshold voltage variations and the effect of upsizing on mean MEP is reported. Finally, it is shown that the product of the read and write lengths provides a knob for trade-off between energy-efficiency and reliable MEP energy operation.

Low-Power Single Bitline Load Sense Amplifier for DRAM

“…Power consumption is a major issue in low-power and portable devices. New types of DRAM, like 2T and 3T1D, have been analyzed and compared, the results show that the minimum-energy point can be reduced by increasing the length of write transistor/boosting write word-line/using high-threshold voltage write transistor methods [12]. Furthermore, the power management mechanism and downscaling method are useful to reduce the energy consumption of DRAM.…”