A 4Gb/s/ch 356fJ/b 10mm equalized on-chip interconnect with nonlinear charge-injecting transmit filter and transimpedance receiver in 90nm CMOS

This paper presents a transceiver for fast and energy-efficient global on-chip communication, consisting of a nonlinear charge-injecting (CI) 3-tap transmit filter (TX) and a sampling receiver (RX) with transimpedance pre-amplifier (TIA). Recently, pre-emphasis techniques have demonstrated significantly better energy-efficiency than repeater interconnects. To further improve energy-efficiency over pre-emphasis techniques that require analog subtraction, our TX selects a pattern-dependent current to inject into the wire, performing feed-forward equalization (FFE) while mitigating the nonlinearity of the driver. This 3-tap charge-injecting (CI) FFE enables stronger equalization than the capacitively driven TX or edge-detection pre-emphasis, achieving data-rate of 4 Gb/s over a 1 cm on-chip wire. The TIA at RX improves bandwidth, signal amplitude, and reduces bias power, breaking the trade-offs in conventional resistor termination, and mitigates equalized signal degradation due to impedance changes in dynamic current sensing.Massachusetts Institute of Technology. Center for Integrated Circuits and SystemsIntel CorporationSemiconductor Research CorporationNational Semiconductor Corporation. Trusted Foundry Service