March 10 kicked off an exciting few days for the Apple semiconductor watcher. First came the rumors of a major shrink of the A5, followed by evidence of no shrink and then pictures of a redesigned die 50-percent smaller than the previous generation. All of this was happening within the humble Apple TV, or should I say Apple's semiconductor test bed.
Very briefly, chatter around a new submission to the FCC for the Apple TV appeared around the start of 2013. On March 10, MacRumors posted an article detailing changes to the A5 processor in the Apple TV. Without providing evidence, the article claimed a die size of 6 x 6 mm, compared with the 8.2 x 8.7 mm of the spring 2012 A5_2 "shrink," which is fabbed with a 32-nm Samsung process. Initial speculation was that this new A5 represented the long-rumored move to TSMC's 28-nm process.
Within a day of publication of the MacRumors article, some bloggers concluded that the 28-nm TSMC process was here, despite the absence of a die cross-section. As I pointed out in a tweet at the time, the approximately 50-percent reduction in die area would actually have required a greater change in process geometry than going from 32 to 28 nm. The whole story really needed some reverse engineering.
Chipworks entered the fray on March 12. Along with some board-level information, their initial posting provided a top metal-level die photo and a cross section. It was the latter that confirmed the "A5_3" was in fact fabricated with a Samsung 32-nm process. So a shrink was no longer in the cards.