• JSTS:Journal of Semiconductor Technology and Science
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• v.15 no.1
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• pp.77-84
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• 2015

This paper presents the design of a low-power, low area 256-radix 16-bit crossbar switch employing a 2D Hyper-X network topology. The Hyper-X crossbar switch realizes the high radix of 256 by hierarchically combining a set of 4-radix sub-switches and applies three modifications to the basic Hyper-X topology in order to mitigate the adverse scaling of power consumption and propagation delay with the increasing radix. For instance, by restricting the directions in which signals can be routed, by restricting the ports to which signals can be connected, and by replacing the column-wise routes with diagonal routes, the fanout of each circuit node can be substantially reduced from 256 to 4~8. The proposed 256-radix, 16-bit crossbar switch is designed in a 65 nm CMOS and occupies the total area of $0.93{\times}1.25mm^2$. The simulated worst-case delay and power dissipation are 641 ps and 13.01 W when operating at a 1.2 V supply and 1 GHz frequency. In comparison with the state-of-the-art designs, the proposed crossbar switch design achieves the best energy-delay efficiency of $2.203cycle/ns{\cdot}fJ{\cdot}{\lambda}2$.