Presentation on theme: "By Jonathan Coup. Crosstalk is the transfer of energy between adjacent conductors due to either capacitive or inductive coupling. In order for crosstalk."— Presentation transcript:
By Jonathan Coup
Crosstalk is the transfer of energy between adjacent conductors due to either capacitive or inductive coupling. In order for crosstalk to occur, there must be an active and passive line in close proximity to each other. Clock and periodic signals are usually the aggressor
Crosstalk has become a more crucial factor in performance due to: ◦ As speed increases so does the edge rate of the signal, more energy at higher frequencies, therefore increased crosstalk ◦ As bandwidth requirements increase and I/O pins on a board increases, the pressure to reduce number of power and ground signals on chip. As a result crosstalk management for these I/O signals becomes a challenge due to minimal ground pin access. ◦ Smaller form factor and lower design costs are forcing tighter spacing between signal traces so then crosstalk between them increases.
The loops inserts a notch in the frequency response of the crosstalk transfer function. The notch frequency and the level of attenuation depends on the perimeter of the loop and distance between loop and victim line
This technique has no negative affects on the signal trace unlike other filter and shielding techniques in use today The smaller the perimeter of the loop the higher in frequency the notch will occur. Here is an example of the frequency response for a single loop.
For additional reduction, more than one open loop resonator can be placed
Uses nonlinear capacitors which have a voltage-dependent capacitance at each stage of the line. The capacitors mitigate the mutual inductance effect and reduce data-dependent signal fluctuation
Here is the depiction of how the non-linear caps are placed This shows the addition of grounded orthogonal grids to further decrease the affects of crosstalk
The yellow trace indicates the input square pulse with a 600 mV peak to peak amplitude. The green trace is the victim line being affected by crosstalk due to the aggressor with the peak to peak voltage listed in the figures. 3 GHz, 5 stage line.
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