Inductive coupling aware explicit cross-talk and delay formula for on-chip VLSI RLCG interconnects using difference model approach

Abstract

In this paper we have proposed a closed form delay and cross-talk noise formula for on-chip VLSI interconnect in the presence of inductive coupling. Inductive coupling effect has become an important issue in high frequency multi-layered VLSI interconnection systems. We first analytically derived the amount of crosstalk noise that would be induced on the quite victim line due to the transiting aggressor line. From that we have proposed an efficient model to estimate the on-chip interconnect delay in the presence of inductive coupling. We also have analytically shown the effect of inductive coupling onto the victim line. Onchip inductive effects are becoming predominant in deep submicron (DSM) interconnects due to increasing clock speeds, circuit complexity and decreasing interconnect lengths. Inductance causes noise in the signal waveforms, which can adversely affect the performance of the circuit and signal integrity. The traditional analysis of crosstalk in a transmission line begins with a lossless LC representation, yielding a wave equation governing the system response. This paper proposes a difference model approach to derive crosstalk in the transform domain. A closed form solution for crosstalk is obtained by incorporating initial conditions using difference modal approach for distributed RLCG Interconnects. An inefficient evaluation of the crosstalk could be at the origin of a malfunction of the circuit. Cross talk can be analyzed by computing the signal linkage between aggressor or attacker nets and victim nets. The attacker net carries a signal that couples to the victim net through the parasitic capacitance. To determine the effects that this cross talk will have on circuit operation, the resulting delays and logic levels for the victim nets must be computed. The comparison made between the results obtained by using our formula and that of SPICE, justifies the effectiveness of our approach. 978-1-4244-6589-7/10/$26.00