A Statistical Approach for Signal and Power Integrity Co-Design in High-Speed Interconnects Considering Non-Linear Power/Ground Noise and Bit-Patterns.

Abstract

In this article, a novel statistical approach is proposed and applied to co-design signal and power integrity (SI/PI) in high-speed interconnects considering the non-linear power/ground noise generated by parallel buffers and bit-patterns. With increased data rates and decreased operating voltages, the allowed noise margin in high-speed interconnects is continuously reduced, and this trend requires SI/PI co-design. Specifically, non-linear power/ground noise associated with simultaneous switching circuits sharing a power delivery network (PDN) and bit-patterns must be carefully considered during the interconnects' design and analysis phase. In many cases, conventional electromagnetic (EM) and transient circuit simulators require heavy computational resources or even fail to deliver an accurate result. The proposed statistical method estimates the statistical eye-diagram in the high-speed interconnect considering power/ground noise and bit-patterns such as data bus inversion (DBI) coding. The accuracy and computational efficiency of the proposed method are validated by comparing the result with HSPICE transient simulation result. The proposed method is also compared with conventional statistical methods, such as peak distortion analysis (PDA) and statistical channel simulation in the transient simulator. Lastly, the proposed method is applied to the SI/PI co-design and co-analysis in the high bandwidth memory (HBM) interposer channel. Impacts of decoupling capacitors on hierarchical PDN impedance, statistical eye-diagram of the HBM channel, and bit error rate (BER) Bathtub curves are summarized. Finally, the BER eye-diagram is derived from the estimated statistical eye-diagram for timing and voltage analysis. The impacts of hierarchical PDN design and bit-patterns on SI/PI are discussed.