Issue link: https://iconnect007.uberflip.com/i/1511130
52 DESIGN007 MAGAZINE I NOVEMBER 2023 Electromagnetic energy propagates at about half the speed of light within the dielectric of a multilayer PCB. is speed is inversely proportional to the square root of the dielectric constant (Dk) of the material. e lower the Dk, the faster the propagation of the wave. In the past, we ignored the board- level delay as it was relatively instantaneous compared to the slow rise time of the signal Just a Matter of Time waveform. But now that we have entered the realm of Gigabit/s design, an unaccounted 10 ps of delay can mean the difference between success and absolute failure of a high-speed design. Also, the trend is toward lower core voltages, which conser ves power. However, reducing the core voltage also reduces the noise margin and impacts the system timing budget. Beyond Design by Barry Olney, IN-CIRCUIT DESIGN PTY LTD / AUSTRALIA