Jennifer Twist, Engineer
Jennifer has been tasked with building an embedded video communications system. She’s been using Arm7 LPC2138 processors in prior designs but needs quite a bit more horsepower for this project so she stepped up to the Arm11 i.MX31 from Freescale. She’s got a few software hotshots that already have experience with the platform so that isn’t a worry. The big deal for her is moving from a relatively easy 64 lead QFP to the much more serious 457 ball .5mm pitch BGA.
She’s used a few small 1mm pitch BGAs before, but never anything close to this. It wasn’t just the package that got to her. She just about said “no” after reading about the 500MHz core speed for the new chip. Fortunately though, the i.MX has a rather large frequency pre-multiplier allowing for a rather sedate 32KHz reference clock to generate the screaming 500MHz+ internal clock. Still, there will be plenty of video speed and other high frequency signals running around. It will be a challenge.
There are some pretty intimidating parts here. A year ago, Jennifer wouldn’t have seen this challenge as anything but fun. The company had three layout specialists with experience on all kinds of high-speed designs. Two of those guys were laid off this spring and the last guy is dedicated to higher priority projects. It would have been nice if she could have gotten some formal training with the layout half of the CAD package but it’s all on-the-job training at this point.