Toshiba, Elpida making memories
helped Apple squeeze more storage in a tight space by delivering a 16 Gbyte NAND flash device that stacks four 32 Gbit die in a single package. The 32 Gbyte version of the phone is expected to pack eight of the dice in a similar package.
Choi said the Toshiba part was the first four-level stack of a 32 Gbit flash die he has seen to date. Intel and Micron released some of the first 32 Gbit parts in January using a 34 nm process. The 210-square mm Toshiba die was probably made in the company's 43nm process using its existing all-bit-line architecture announced about 18 months ago.
An Intel/Numonyx device new to the iPhone provides memory for the baseband processor. Choi said he believes it includes a 16 Mbyte NOR die and a 512 Mbit Elpida DRAM die, although he has yet to conduct detailed chip-level analysis on the part.
One of the biggest mysteries of the 3GS is the applications processor widely expected to be an upgraded version of the 90nm Samsung part in the first two generations of the iPhone. As with the earlier designs, the package markings on the chip do not correlate directly to anything in the Samsung product portfolio.
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The package bears both Apple and ARM logos along with numbering suggesting a Samsung memory multichip package, Choi said. He plans to conduct a detailed cross-section analysis of the chip, measuring transistor sizes and other key metrics.
Many observers speculated the part includes a 600 MHz ARM Cortex A8 and PowerVR SGX graphics core from Imagination Technologies in an SoC made in a 65nm process. Such a chip would be on par with the OMAP 3430 from Texas Instruments used in the Palm Pre.
"That's based on speculation and press releases," said Choi. "We haven't yet identified any functional blocks to determine what [the Samsung part] actually is," he added.
Indeed, even the markings on the die of the applications processor (pictured below) do not describe the heritage of the part.
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It's also possible the design is a custom ASIC built for Apple. The company has been working for more than a year to build up a strong internal semiconductor team to define proprietary silicon for its systems.
Carey said the apps processor includes two 128 Mbyte Elpida Mobile DDR SDRAMs in a stacked package-on-package. That gives the 3Gs processor 256 Mbytes of working memory, and another design win for Elpida in the high profile handset market. Elpida mobile SDRAM was also found in the Palm Pre.
"The use of a new Samsung apps processor and an Omnivision auto-focus 3 Megapixel camera certainly bumps the costs up, but these improvements along with a few incremental bells and whistles would seem to be offset by declines elsewhere in the system," said Carey.
Another surprise is the new handset apparently still uses the Infineon PMB8878 also known as the XGold 608 baseband processor in previous designs, according to Carey of Portelligent. Apple doubled to 7.2 Mbits/second the download speed supported on the iPhone 3GS, but that speed grade was apparently already supported on what is clearly the old Infineon chip based on die markings.
Some other findings from Portelligent included: the 3-axis compass chip (used in the new GPS feature of the phone) being manufactured by AKM Semiconductor, the audio codec coming from Cirrus Logic, and Dialog Semiconductor providing the power management unit for the application processor.
Infineon again found themselves a major IC design-in benefactor in the iPhone 3Gs; with their baseband processor, power management chip (the SMARTi Power 3i), and their UMTS transceiver (used in the original iPhone 3G) all finding themselves in this new iPhone.