Apple A4 system-on-chip architecture observed by infrared imaging through the backside of an intact die.

Detail of ARM Cortex-A8 block from Apple A4 obtained by backside infrared imaging technology.

Apple’s A4 dissected, discussed…and tantalizing….

The Apple A4 discussion kicked off in earnest when Steve Jobs introduced the iPad on January 27. In an infamous series of slides tracing the roots of Apple back to the two Steves in his garage, Jobs introduced the Apple A4 processor that powers the iPad, operating at a clock frequency of 1GHz.

The first question was whether the A4 could be the first offspring spawned by Apple’s April 2008 acquisition of PA Semi. However, it seemed there was not enough time for a brand new design. Jon Stokes provided an interesting early insight into the CPU-GPU combination and the potential role of PA Semi.