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Inside Apple's iPad 2 A5: fast LPDDR2 RAM, costs 66% more than Tegra 2

The new A5 processor used by iPad 2 incorporates Samsung's new 46nm Low Power DDR2 memory, uses a variable clock speed and costs about $25, a significant premium over NVIDIA's competing Tegra 2.

According to research performed by UBM TechInsights, Apple's larger A5 (12.1mmx10.1mm, compared to the 7.3mmx7.3mm A4) costs about $25 to build, making it $10 more expensive than similar dual core chips such as the Tegra 2 used by the Motorola Xoom.

Even so, the firm estimates the iPad 2 total Bill Of Materials costs about $270, compared to its BOM estimate of the Xoom, which weighs in at $288 (both numbers compare 32GB 3G versions).

Cheaper by the million dozen

"To help with their margins," UBM engineer and technical marketing manager Allan Yogasingam told AppleInsider, "this basically guarantees the A5 will be in most next generation Apple products like the iPhone 5 and the iPod Touch. It will help bring the costs down to the $15 range of their competition - especially if they have a plan in place to ramp up production through another fab like TSMC."

Yogasingam noted that despite rumors that Apple may be working with TSMC to build A5 chips, "the A5 in our possession is definitely manufactured by Samsung using their 45nm process."

"Our first inclination that this could be a Samsung manufactured processor was the similarity in word mark between this font and the font in the Apple A4," the Yogasingam stated (below, A4 wordmark is in the inset image.)

The A5 up close, really close

UBM TechInsights also said it "used optical die and SEM cross-section images to analyze features such as die edge seal, metal 1 pitch, logic and SRAM transistor gate measurements. These features were then compared to other manufacturers in our database, including other Samsung 45nm parts," indicating that the A5, like the previous generation Apple A4 processor, was built using Samsung’s 45nm process.

Apple A5 die full die photo

Yogasingam provided a full scale die photo of the Apple A5 Processor (above). A side view image of the A5 processor reveals the package-on-package of the processor and low-power DDR2 DRAM (below).

Apple A5 die pop

A SEM (Scanning Electron Microscopy) cross-section image showing the SRAM transistors in the Apple A5 processor (below).

Apple A5 die xsection

Evolution of Apple's APL chips

Apple has used a series of Applications Processors in its iPhone, iPod touch and iPad models since 2007. Initial versions of the chips were designated as 8900B series, while later versions were labeled in an APL series. Only last year did Apple begin naming its processor as "the A4," a step similar to the company's previous branding of third, fourth, and fifth generations of PowerPC chips the G3, G4 and G5.

A5 evolution

In addition to much faster graphics based on the dual core SGX543MP2 graphics technology licensed from Imagination Technologies, the A5 also boasts dual processing cores based on ARM Cortex A9, with a dynamically set clock speed.

Dynamic clock, faster RAM

"While the A4 clock speed was steady at 1 GHz," Yogasingam said, "the A5 clock speed varies depending on the application being run. This would indicate an advanced power management circuitry controlling the clock speeds of the cores—something new for the A5 and may explain the use of a different power management IC from Dialog Semiconductor."

Also notable in the A5 is the use of fast new Low Power DDR2 DRAM memory. "What is also interesting is that teardowns performed at two UBM TechInsights locations (in Austin and Ottawa) revealed two different LPDDR2 DRAM from two different manufacturers (Samsung and Elpida). The Samsung K4P2G324EC LPDDR2 die is the first time we’ve seen Samsung’s new 46nm LPDDR2 memory. This also tells us that Apple is fully prepared to package multiple LPDDR2 offerings."

Apple A5