Update: So the iFixit disassembly continues, and some interesting tidbits have emerged. The battery is pretty huge -- a 3.75V, 24.8 watt-hour job, weighing in at 148 grams. There are some significant differences between the retail unit and what we saw at the FCC, including the A4 processor, which looks to be manufactured by Samsung.
Update 2: Talk about some wild findings. The iFixit crew has discovered that the iPad's battery has 5.5x the capacity of the battery in the iPhone, with two batteries wired in parallel, for a total of 24.8 Watt-hours. On average, the unit sips just 2.5 Watts (one-fifth the power of a compact fluorescent bulb), and the rear case is machined from a single billet of aluminum. We're told that the "empty void in the upper right corner is where the cellular communications board would go in the 3G iPad," and "the A4 is a Package-on-Package (PoP), with at least three layers of circuitry layered on top of each other." Care for more? Head past the break for the bullet points.
iFixit iPad teardown findings so far:
- The iPad's battery has 5.5x the capacity of the battery in the iPhone! The iPad actually has two batteries wired in parallel, for a total of 24.8 Watt-hours.
- On average, the iPad sips just 2.5 Watts. That's 1/5 the power of a compact fluorescent bulb!
- The rear case is machined from a single billet of aluminum, increasing weight but greatly improving the rigidity of the device.
- The empty void in the upper right corner is where the cellular communications board would go in the 3G iPad.
- The A4 is a Package-on-Package (PoP), with at least three layers of circuitry layered on top of each other. A4 is packaged just like the iPhone processors, microprocessor in one package and two memory modules in the other package. They're all sandwiched together in a very nice and thin PoP.
- The iPad RAM is INSIDE the A4 processor package. Confirming this took quite a bit of sleuthing: we had to partner with Chipworks to X-ray the processor. The X-ray revealed two layers of RAM. In addition to the ARM processor, the A4 package contains two stacked Samsung dies.
- We will be releasing a detailed analysis of the A4 in conjunction with Chipworks in a few days.
- The rumored slot for a camera is actually taken up by the ambient light sensor.
- The glass panel is quite thick: about 1.18 mm, compared to the iPhone's 1.02 mm thick glass. This is necessitated by the panel's large size.
- The touch circuit design is more similar to the old 2G and early 3G iPhones than the current 3GS. Chipworks informed us that "there is so much room in the iPad that Apple didn't need to use small chips, just the right ones and cheap ones."