Investigations on the use of negative-resistance terminations for multi-drop bus channels

This paper investigates the potential benefits of using termination circuits with negative effective resistance for multi-drop bus channels, whose applications include high-speed, high-capacity memory interfaces. Signals propagating through multi-drop channels can experience reflections at the split junctions, significantly degrading the signal integrity and limiting the maximum data rates. Rather than passively matching the impedances at those junctions with resistors that lowers the signal swing arriving at each receiver, a negative-resistance circuit that actively restores both the desired impedance and the signal swing is proposed. Measurement results demonstrate its feasibility and suggest that the active circuits distributed along the channel can also compensate the channel losses.