A 5-Gb/s adaptive CTLE with eye-monitoring for multi-drop bus applications

On-chip data processing capabilities have increased very rapidly over the last decades creating off-chip bandwidth a strong limiting factor. Limitations of this off-chip communication originate from interconnect, vias and connectors leading to reflections over chip-to-chip interconnect and leads to intersymbol interference. These variations dynamically change based on interconnect length, number of vias and connectors, needing adaptive equalization. This scenario becomes worse and unpredictable in a multi-drop bus environment, leading to complete eye closure. In this work, we propose a 5 Gb/s adaptive continuous time linear equalizer (CTLE) with eye-monitoring in a multi-drop bus environment. The coefficients of CTLE are adjusted to compensate the channel nonlinearities based on the feedback received from the eye-monitoring device. Adaptive CTLE is designed in 1.8V, 0.18μm CMOS technology for 5 Gb/s data transmission over a 7.5 inch FR4 PCB trace. The power consumed by adaptive CTLE is 18mW for a bit error rate of 10^-12.