Capacitively Driven Global Interconnect With Energy-Efficient Receiver Based on Magneto-Electric Switching

We model a capacitively driven, low-swing, global interconnect circuit based on a receiver that utilizes magnetization switching induced by the magneto-electric (ME) effect. Capacitively driven wire was recently shown to be effective in improving the performance of global interconnects. Such techniques can reduce the signal swing in the interconnect with the use of a capacitive divider network, which does not require an additional voltage supply. However, the large reduction in signal swing makes it necessary to use differential signaling and amplification for successful regeneration at the receiver, which add wire area and require static power. The ME effect has been shown to reverse the magnetization of a nanomagnet by applying a low voltage to an adjacent multiferroic oxide. Here, we propose a receiver based on the ME effect that uses the low voltage at the receiving end of the global wire to switch a nanomagnet. The nanomagnet is also used as the free layer of a magnetic tunnel junction (MTJ), the resistance of which is tuned through the ME effect. This change in MTJ resistance is converted to full-swing binary signals with simple digital components. This process allows capacitive, low-swing interconnection without differential signaling or amplification, which leads to significant energy efficiency. Our simulation results indicate that for 5-10 mm long global wires in IBM 45 nm technology, the capacitive ME design consumes one third the energy of a full-swing complementary metal-oxide semiconductor (CMOS) design and one half the energy of a differential amplifier low-swing capacitive CMOS design.