A5

There are four variants of the A5 system-on-a-chip:
 * S5L8940 (A5) - used in most variants of the iPad 2 and the iPhone 4S.
 * S5L8942 (A5 Rev A) - used in the original Apple TV 3G, iPad 2 (Wi-Fi model) [Rev A], iPod touch 5G, and iPad mini 1G.
 * S5L8945 (A5X) - used in all variants of the iPad 3
 * S5L8947 (A5 Rev B) - used in the revised Apple TV 3G