We are used to the usual teardowns, that usually involve ripping a physical device apart, but iFixit has torn down the actual A7 silicon that we find in the Apple iPhone 5S. iFixit used an Ion Beam Etcher, which takes layers off of a semiconductor, analyzing just how it is made. iFixit worked with Chipworks on the A7 teardown, discovering quite a bit:
- First, a biggy: "We have confirmed through early analysis that the device is fabricated at Samsung's Foundry. We suspect we will see Samsung's 28 nm Hi K metal Gate (HKMG) being used."
- The distance between each of the chip's transistors is 114 nm, compared to the A6's 123 nm.
- That 9 nm difference - from a 28 nm process to a 32 nm process - means the same computational power can be squeezed into just 77 per cent of the original area. But given the A7 is larger than the A6, it's clear where all that poke came from.
- In total, the A7 packs one billion plus transistors onto a 102 square millimetre field.
- Chipworks claims that the M7 section of the silicon is an NXP LPC18A1 - part of the LPC1800 series of high-performing ARM Cortex-M3 based microcontrollers.
- In fact, the M7 packs accelerometer, gyroscope, and magnetometer, and does some fancy maths before neatly passing orientation data to the main chip.
- The Wi-Fi module is exactly the same as that in the iPhone 5.
- The 4G LTE modem uses two chips: a Samsung-fabricated LTE baseband processor and a Samsung DRAM module to retain carrier specific information.