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MAY 2022 I DESIGN007 MAGAZINE 29 • On-die terminations (ODT) can be used with some memory devices to match the transmission line and dampen the reflections. • Drivers do not have the same impedance as the transmission line (typically 10–35 Ω) so series terminations are used to balance the impedance, match the line, and minimize reflections. • e easiest way to reduce crosstalk from a nearby aggressor signal is by increasing the spacing between the signals. • Reducing the signal trace to reference plane dielectric thickness can also reduce crosstalk while not requiring additional space. • Plane pairs in multilayer PCBs are essen- tially unterminated transmission lines. • If the plane cavity is mismatched or unterminated, there will be standing waves—ringing. DESIGN007 Resources 1. Beyond Design columns by Barry Olney: "The Fundamental Rules of High-Speed PCB Design, Part 2;" "Stackup Configurations to Miti- gate Crosstalk;" "Controlled Impedance Design;" "Plane Cavity Resonance;" "Dampening Plane Resonance with Termination;" "Signal Integrity, Part 3." Errata: In the February 2021 issue of Design007 Magazine, the Beyond Design column, "Stackup Configurations to Mitigate Crosstalk," contained two errors in equations 1 & 2. The term Lm/Cto- tal should have been Lm/Ltotal. Please down- load the revised PDF to replace your library copy today. Barry Olney is managing direc- tor of In-Circuit Design Pty Ltd (iCD), Australia, a PCB design service bureau that specializes in board-level simulation. The company developed the iCD Design Integrity software incorporating the iCD Stackup, PDN, and CPW Planner. The soft- ware can be downloaded at To read past columns or contact Olney, click here. Dutch submersible manufacturer U-Boat Worx breaks the mould with the launch of the NEXUS series. U-Boat Worx is the market leader in private and commercial submersibles. The NEXUS series comprises two models fea- turing an ultra-large elliptical acrylic pressure hull with unrivalled passenger comfort. Seating up to eight passengers and one pilot, the NEXUS pro- vides 25% more interior space than competing models. The NEXUS subs are depth-rated to 200 meters (650 feet). Equipped with the latest lithium-ion battery tech- nology, the subs can operate for up to 18 hours and dive up to ten times a day. 80 guests can partici- pate in an unforgettable sub-sea adventure daily. The unique revolving seating arrangement fea- tured in the Cruise Subs has been replicated in the NEXUS. Passengers therefore always enjoy the best view, regardless of the direction the subma- rine is travelling. The NEXUS subs are designed as multi-directional, meaning they can manoeu- vre in any direction without compromise. This is a distinguishing capability only achieved in U-Boat Worx submersibles. Ten silent thrusters provide the power required for top performance and unmatched speed. The experience and knowledge gained from the development of the Cruise Subs has evolved the new features in the NEXUS series, including an XXL entrance hatch, the largest ever incorporated on a submersible of this size. The NEXUS is optimised for ship-based launch and recovery and can also be deployed from land and transported to dive sites. (Source: ACN Newswire) U-Boat Worx Launches 9-person Flagship Lithium-ion Battery Submersible NEXUS

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