On-Package Continuous-Time Linear Equalizer using Embedded Passive Components

Multi-gigabit input/output (I/O) links on printed circuit boards (PCBs) suffer from high-frequency signal attenuation, necessitating equalization to restore the transmitted waveforms. Whereas active transmitter or receiver equalization circuits consume significant power, equalizers composed exclusively of passive devices can achieve good signal integrity with no active power dissipation. Recent advances in packaging technology allow passive devices to be integrated directly into the substrate, thereby freeing area in the die or on the motherboard that would otherwise have been needed for the equalizer. In this paper, we are reporting the first, experimental demonstration of continuous-time linear equalizers (CTLEs) using embedded passive components up to 10 gigabit per second (Gbps). We have designed, optimized and fabricated three different equalizers using embedded passives technology. These devices were employed to a equalize board-level interconnect suffering from frequency-dependent loss. We have then validated the performance of the CTLEs in the frequency and time domains.