Article,
Design and Analysis of Power and Variability Aware Digital Summing Circuit
International Journal on Communication, 2 (2): 9 (July 2011)
Abstract
Due to aggressive scaling and process imperfection
in sub-45 nm technology node Vt (threshold voltage) shift is
more pronounced causing large variations in circuit response.
Therefore, this paper presents the analyses of various popular
1-bit digital summing circuits in light of PVT (process, voltage
and temperature) variations to verify their functionality and
robustness. The investigation is carried with ±3ó process
parameters and ±10% VDD (supply voltage) variation by applying
Gaussian distribution and Monte Carlo analysis at 22 nm
technology node on HSPICE environment. Design guidelines
are derived to select the most suitable topology for the design
features required. Transmission Gate (TG)-based digital
summing circuit is found to be the most robust against PVT
variations. Hence, a TG-based digital summing circuit is
implemented using carbon nanotube field effect transistor
(CNFET). This implementation offers tighter spread in
propagation delay (3×), power dissipation (1.14×) and EDP
(energy delay product) (1.1×) at nominal voltage of VDD = 0.95V
compared to MOSFET-based (TG – topology) digital summing
circuit implying its robustness against PVT variations.
