Issue link: https://iconnect007.uberflip.com/i/952929
14 DESIGN007 MAGAZINE I MARCH 2018 facturability." We talked about that, putting things one side of the board or the other. DFX, or "design for excellence." Your tool is directly addressing cost. Chitwood: Yes, directly from a decap BOM point of view and indirectly from a stackup and DC point of view. Dack: Speaking of which, let's cap it off with a discussion about DC. DC is huge. Chitwood: To my knowledge, the Cadence Sig- rity PowerDC™ technology was the first tool to combine electrical and thermal into one co-simulation environment, with literally one button-push where you get an electrical result and a thermal result, all within one GUI. That, as you can imagine, has been tremendously popular. For example, how many amps can be put through a specific via? How many vias are needed to move ten amps from one layer to another layer? Sigrity technology was the pio- neer in this application. Dack: That's power-related and therefore ther- mal-related? Chitwood: Yes, power and thermal are very much interrelated. I joke that you never want to see an email with the word "fire" in it. I've seen customers have some creative ways of describing such a situation to their manage- ment. They may say that they've had, for instance, an "exothermal event." Another good one is "light charring" of a PCB. But my per- sonal favorite is "projectile vias." Dack: I haven't heard of that. We used to talk about, "It's OK if it gets warm, and it's OK if it gets hot, but it fails when it lets the smoke out." Chitwood: Agreed! We had a customer come to us specifically for this thermal capability because they had a cascade failure that melted vias out of their board. They thought they had sufficient number vias, but analysis showed the vias were not placed correctly. Dack: Circuit board materials aren't typically manufactured or designed to handle heat. Heat is the enemy of circuit boards. Z-axis thermal expansion is just not good for vias anyway, regardless of whether they go projectile or not. Chitwood: Let's remember that the "FR" in FR-4 stands for fire-retardant, not fireproof! Dack: Anything else you'd like to mention that we've missed? Chitwood: Cadence has recently released new