[Kindle 2 Teardown] Kindle Grows Out of Reference Design [Part 3]

May 14, 2009
Nikkei Electronics Teardown Squad
The back covers were taken off from the Kindle 2 (left) and the Kindle (right).
The back covers were taken off from the Kindle 2 (left) and the Kindle (right).
[Click to enlarge image]
The main board of the old model
The main board of the old model
[Click to enlarge image]
The main board of the new model
The main board of the new model
[Click to enlarge image]

Continued from [Kindle 2 Teardown] New Model More Difficult to Tear Down [Part 2].

We finally took off the back cover of the Kindle 2, sometime after removing the back cover of the Kindle.

"Oh, this is very tidy," said the engineer who participated in the teardown. "They completely revamped the design."

The exposed main boards of the new and old Kindles were clearly different from each other. While the old one was crammed with components, there was no double that the new one had much fewer parts and was well organized.

To analyze the main boards in detail, we removed them from the front covers of the chassis and looked at the back sides of the boards. The back side of the new Kindle's main board was mounted with no part. In contrast, many components, including Samsung Electronics Co Ltd's 256-Mbyte NAND flash memory, were found on the back of the old Kindle's main board, reinforcing the impression that the old model is complicated and the new model is simple.

The engineer started to analyze the difference between the two main boards, examining the components mounted on them.

"The old model adopted the reference design, without making any changes, that drives E Ink's electronic paper," he said. "They probably thought, 'we have to drive the device by all means.' As a result, the number of parts increased, and the design became complicated. On the other hand, looking at, for example, the microprocessor, the circuit architecture of the new model was designed from scratch. It's like they adopted a design concept used for a mobile phone."

In other words, the engineer pointed out that the new model grew out of the reference design and was designed to make the main board simpler.

The main boards of the new and old Kindles were mounted with the following components. The microprocessor used in the old Kindle was Intel Corp's "XScale 255" (Intel sold its unit selling products including the XScale 255 to Marvell Technology Group Ltd in June 2006), and the USB controller IC was the product of NXP Semiconductors. Also, the old model was equipped with two synchronous DRAMs manufactured by Infineon Technologies AG.

On the other hand, the microprocessor on the new Kindle's main board was Freescale Semiconductor Inc's "iMX31," which is intended for mobile phones, etc. Probably, the USB controller function was incorporated in this microprocessor. Both the 2-Gbyte NAND flash memory and two synchronous DRAMs were products of Samsung Electronics.

*Nikkei Electronics estimated the above information. As for the company names, we referred to the names printed on chips. So they might be different from the names currently used.

We moved on to examine the electric paper.

To be continued