What’s in the A5 processor powering Apple’s iPad 2?

Apple introduced the iPad 2 yesterday and revealed that there was a new processor inside, the A5, to power the iPad 2’s new features including the two cameras and the FaceTime video chat feature. The A5 processor is the successor to the A4 found in the original iPad and the latest incarnations of Apple’s iPhone. We don’t yet know much about Apple’s A5 processor, but there are some things we do know.

In the iPad 2 rollout, Apple gave a few specifications for the A5 including the use of two 1GHz ARM cores, up from the A4 processor’s single-core design. Apple also disclosed that the graphics capability had been greatly enhanced, with performance goosed by a factor of 9x. Some pundits had predicted that the graphics performance would quadruple, so their expectations were a bit low. Others are guessing that Apple stepped up from the Imagination Technologies PowerVR SGX535 GPU used in the A4 processor to the PowerVR SGX543 GPU, which employs four graphics-processing pipelines to render 35 million polygons/sec. Certainly, the PowerVR SGX543 GPU’s performance falls into the right range for Apple’s stated performance.

Equally important, the Apple A4 processor is a multichip design that employs PoP (package-on-package) assembly. According to Wikipedia, the iPad version of the A4 processor (http://en.wikipedia.org/wiki/Apple_A4) includes two 128Mbyte LPDDR SDRAM chips for a total of 256Mbytes of DRAM. Apple Insider reports that Kakeun Lee, a Korean semiconductor analyst, has used Twitter to speculate that the Apple A5 processor incorporates 512Mbytes of LPDDR2 DRAM, with a 1066 Mtransfer/sec transfer rates instead of the 800 Mtransfers/sec of the Apple A4. (For more info on LPDDR2, see my blog post on the Denali Memory Report “LPDDR2: The new mainstream memory for embedded and mobile applications?”)

Apple has not commented on the amount of RAM in the iPad 2—for now.

One really interesting aspect of the iPad 2 is that Apple is making a big deal about how thin the product is. “It’s thinner than an iPhone 4” exclaimed Steve Jobs at the introduction. The thin profile was partially achieved by redistributing the battery and electronics so that they are side by side, reducing the amount of physical layering in the product. Not said, but equally important is Apple’s use of PoP packaging for the A4 and A5 processors, which also helps reduce the volumetric requirements of the internal electronics.

Certainly, we can expect the inevitable teardowns to reveal more as soon as the iPad 2s become available.

About sleibson2

EDA360 Evangelist and Marketing Director at Cadence Design Systems (blog at https://eda360insider.wordpress.com/)
This entry was posted in Apps, ARM, EDA360, Silicon Realization, SoC Realization, System Realization and tagged , . Bookmark the permalink.

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