Models Built With Water


A couple of years ago I wrote a post using the famous quote by statistician George Box: All Models Are Wrong; Some Are Useful. In that post, I discussed paper and plastic airplanes, but mostly I talked about modeling in computers, and especially what I call the "digital illusion." The digital illusion is the idea that signals in digital chips are ones and zeros, with timing, and not analog vol... » read more

Choosing Between Static and Dynamic Shapes


That title might be a touch misleading. We’re not here to talk about why to convert shapes between static and dynamic. Rather, I want to talk about why you should NOT be doing this. Every design has some conductor shapes in it (or at least a very large percentage of them). What style to use is a choice that will impact performance through your entire flow; let the shape’s purpose guide you.... » read more

Easier Bond Finger Solder Mask Openings


If you design wire bond packages, you’re familiar with the need for the bond fingers and rings on the package substrate layers to be exposed through the solder mask layer. If they aren’t, it becomes… rather difficult… to bond the wire to them, after all! We talked about general-purpose bounding shapes a few weeks ago in “A Boundless Bounty of Bounding Shapes”. Bond fingers have a... » read more

Demystifying Mirror Types


I’m not talking about carnival funhouse mirrors, but rather the different options for mirroring symbols, vias, and bond fingers in your IC Package layout. The Allegro Package Designer Plus and SiP Layout tools have two distinct styles of mirroring which are used in different places. Often, I get questions about what, exactly, those differences are. And even more, why the styles are used for d... » read more

Moore And More


For more than 50 years, the semiconductor industry has enjoyed the benefits of Moore's Law — or so it seemed. In reality, there were three laws rolled up into one: Each process generation would have a higher clock speed at the same power. This was not discovered by Moore, but by Dennard, who also invented the DRAM. Process generations continue to get faster and lower power, but the power... » read more

Brains And Computers At The VLSI Design Conference


One of the industry’s biggest events, the VLSI Design Conference, took place in Bangalore last week. This conference does a round-robin of cities, and this was the 10th time in its 33-year history that Bangalore was hosting it (the last time was in 2015). This year’s conference attracted over 1,800 technologist and leaders over five days – a huge turnout for this growing industry. Inci... » read more

System-in-Package For Heterogeneous Designs


System integration is increasingly being done using 3D packaging technologies rather than integrating everything onto a huge SoC. One motivation is the ability to not just to split up a design in a single process, but to package die from different processes. Sometimes there are economic reasons. Several presentations at HOT CHIPS had a partition of the design into the processor itself, and a... » read more

Mary Jane Irwin Receives The Kaufman Award


Mary Jane Irwin just got back from a cruise around the Greek islands with her husband of 53 years to celebrate being the first woman to receive the Kaufman award. When I wrote my post The 2019 Kaufman Award Goes to Mary Jane Irwin about her receiving the awards last week, I mostly just used the boilerplate biographical information from the press release. But that's rather dry, so I called her u... » read more

Scan Compression Is No Longer About Compression


Scan compression was introduced in the year 2000 and has seen rapid adoption. Nearly every design’s test methodology today implements this technology, which inserts compression logic in the scan path between the scan I/Os and the internal chains. In this article, we take a critical look at the technology to understand how scan compression has matured. The road to scan compression Since th... » read more

IC Test: Doing It At The Right Place At The Right Time


In the real world, we are slaves to our environment. The decisions we make are dependent on the resources available at any given time. In school, I remember coming up with a binary decision diagram (BDD) variable-ordering algorithm that relied on partial BDDs. Was that the best algorithm to determine the variable ordering of a BDD for a design? Probably not. However, it was easy to do as a coll... » read more

← Older posts