One astonishing part of the iPad announcement was the adoption of the brand-new A4 microprocessor. But how is the A4 system-on-a-chip (SoC), trumpeted as the next-gen model designed by Apple itself, different from the microprocessors used in the iPhone series? We took an iPad apart to see just what makes it tick.
Steve Jobs told the eager crowd that the iPad runs on a chip developed by Apple Inc. of the US itself. He said the new chip, called the A4, was the best chip the firm has ever worked on. The site was the iPad press conference called by Apple in San Francisco, California in late January 2010.
Jobs revealed that the A4 runs at 1GHz, and single-chips the processor, graphics, input/output (I/O) and memory controller. Official Apple press releases also described the A4 as a next-generation SoC designed in-house, and stressed that it was a key component of the iPad.
Apple's announcement of the A4 drew attention from the industry and the media, with technical people in both fields expressing diverse opinions. Some suggested that it was developed using technology from fabless semiconductor manufacturer P. A. Semi, Inc. of the US, which Apple acquired in April 2008, while others thought it must be an upgrade of the iPhone processor because it could run iPhone apps.
Nikkei Electronics was also very interested in the A4, and we wondered just what "developed by Apple" might really mean. We have taken apart iPhones in the past, and each time we found a processor boasting the Apple logo on the package, but the general opinion in the industry is that these processors are all actually manufactured by Samsung Electronics Co., Ltd. of Korea. Matching model numbers have not been found elsewhere, suggesting that the chips are custom designs ordered by Apple from Samsung. But how are they different from the A4, if at all?
The top of the processor package tells us nothing, and even an X-ray of the wiring pattern on the inside would be meaningless. We decided to remove the A4 from the board, strip off the package, and take a close look at the die itself. The first step was to find engineers to help us analyze the A4.
We received our first offer of help for analysis in March 2010, about one month before the iPad was put on sale in the US. We obtained an iPad, took it apart and investigated the board in details, then took it to the offices of our new partner to begin analysis of the A4.
Nikkei Electronics |
Nikkei Monozukuri |
Nikkei Automotive Technology |
|---|---|---|
 |
 |
 |
| The magazine for electronics designers and managers. | Design You Won't Regret - How to Reduce the Risk of Accidents | The comprehensive automotive technology magazine. |
Copyright © 1995-2010 Nikkei Business Publications, Inc. All rights reserved.
All editorial content and graphics on this Web site may not be reproduced in whole or in part without the express permission of the copyright owner.
