Crosstalk analysis and repeater insertion in crosstalk aware coupled VLSI interconnects

Abstract

Purpose

To analyze factors affecting crosstalk and to study the effect of repeater insertion on crosstalk, power dissipation and propagation delay.

Design/methodology/approach

Crosstalk is effected by transition time of the signal; length of interconnect; distance between interconnects; size of driver and receiver; pattern of input; direction of flow of signal; and clock skew. This work is based on simulating interconnects with parameters obtained from 0.13 μm process. The types of noise addressed are overshoot; undershoot and oscillatory noise. Further, to study the effect of repeater insertion on crosstalk, repeaters are inserted in one line, i.e. line A only. Uniform repeaters varying in number from 1 to 60 are each of size W_n=3.9 μm and W_p=7.8 μm. Both lines A and B are terminated by a capacitive load of 5 fF. A crosstalk noise effect is measured for line A loaded with repeaters. The number of repeater is varied for four different cases of stimulations to both lines viz. input to line A, i.e. V_A switching from low to high; input to line B, i.e. V_B switching from low to high; input to line A i.e V_A switching from low to high; input to line B, i.e. V_B switching from high to low; V_A switching from high to low and V_B at static low; V_A switching from high to low and V_B at static high.

Findings

This paper shows the prominent factors such as edge rate, length and pattern of inputs affecting the noise. It is observed that presence of inductive effects can seriously hamper the functioning of the chip. This paper further reveals that repeater insertion not only reduces the propagation delay but also crosstalk levels for coupled lines. Repeaters can be efficiently utilized for reduction of propagation delay and crosstalk noise at a trade of marginal increase in power dissipation. The power‐delay‐crosstalk‐product (PDCP) criterion is introduced as an efficient technique to insert repeater in coupled interconnects. Based on PDCP a reduction in crosstalk of about 60 times and delay of 4.2 percent is achieved at trade of 13.2 percent increase in power dissipation in comparison to PDP.

Originality/value

The PDCP criterion is introduced as an efficient technique to insert repeater in coupled interconnects. Instead of PDP criterion, PDCP criterion is best suited for determination of optimum number of repeaters for overall minimization of delay, power and crosstalk.

Citation

Kaushik, B.K., Sarkar, S., Agarwal, R.P. and Joshi, R.C. (2006), "Crosstalk analysis and repeater insertion in crosstalk aware coupled VLSI interconnects", Microelectronics International, Vol. 23 No. 3, pp. 55-63. https://doi.org/10.1108/13565360610680776