![]() Now with the simulation sketched up, I want some simulation results. This is obviously less flexible, but sufficient for this simple analysis. The length of the transmission line is set in a dialog box, where all unrouted nets are given the same length and impedance: In this process, I select the TYP models, as Altium, unfortunately, requires you to select the process corner when the IBIS file is imported – more on this annoyance later. Models from the IBIS file are loaded and attached under the schematic library symbol. In Altium you have to draw this with the actual schematic symbols and as a minimum connect power and ground with special net information parameter set symbols. Note: You can click all images to have them blown up in a more readable size.Īltium Designer is different. The sketch for the analysis is set up like this with the I/O driving a pulse into a transmission line (ideal 0.5ns, 50R) to the input. Sketch up the circuitĬadence calls their tool SigExplorer in OrCAD PCB SI (we are on version 16.5 here). Both questions need a quick and decent but not obsessively accurate answer. My initial thinking is: “This is a fast device, but is it fast enough to require a series termination resistor?” and “What would the ideal series termination resistor value be?”. And yes this is a very simple analysis – but also very similar to what you would do with the latest DDR memory device or whatever is hot for you right now.Ĭan’t remember a 74ALVC244? Here is an example datasheet from TI: This is Part I of that test.įor this test, I picked a simple analysis of one 74ALVC244 output (can be tri-stated, but I want to look at the output enabled case only) driving one of the inputs. So just how well does this cheap simulator in Altium Designer handle realistic simulations? I decided to do a few comparisons to test out the Altium Signal Integrity simulator. We are used to fairly expensive dedicated SI tools from the big players like Hyperlynx from Mentor and SigExplorer from Cadence. The price is right – you basically get the SI simulator for free as part of the schematic/layout/mechanical etc. How good is Altium for signal integrity? This is a question I get asked a lot.
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