Apple A4

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Apple A4
General information
LaunchedMarch 2010
Designed byApple Inc.
Common manufacturer(s)
Performance
Max. CPU clock rate800 MHz (iPod Touch 4th Generation)  to 1 GHz (iPad) 
Cache
L1 cache32 kB Instruction + 32 kB Data
L2 cache640 kB
Architecture and classification
Technology node45 nm
Instruction setARM v7
Physical specifications
Cores
  • 1
History
Successor(s)Apple A5

The Apple A4 is a package on package (PoP) system-on-a-chip (SoC) designed by Apple and manufactured by Samsung.[1] It combines an ARM Cortex-A8 CPU with a PowerVR GPU, and emphasizes power efficiency.[2] The chip commercially debuted with the release of Apple's iPad tablet;[3] followed shortly by the iPhone 4 smartphone,[4] the 4th generation iPod Touch and the 2nd generation Apple TV. It was superseded in the second-generation iPad, released the following year, by the Apple A5 processor.

Design

Apple A4 is based on the ARM processor architecture.[5] The first version released runs at 1 GHz for the iPad and contains an ARM Cortex-A8 CPU core paired with a PowerVR SGX 535 graphics processor (GPU)[3][6][7][8] built on Samsung's 45-nanometer (nm) silicon chip fabrication process.[9] Clock speed for the units used in the iPhone 4, iPod Touch, and Apple TVs have not been revealed.

The Cortex-A8 core used in the A4 is thought to use performance enhancements developed by chip designer Intrinsity (which was subsequently acquired by Apple)[10] in collaboration with Samsung.[11] The resulting core, dubbed "Hummingbird", is able to run at far higher clock rates than other implementations while remaining fully compatible with the Cortex-A8 design provided by ARM.[12] Other performance improvements include additional L2 cache. The same Cortex-A8 CPU core used in the A4 is also used in Samsung's S5PC110A01 SoC.[13][14]

The A4 processor package does not contain RAM, but supports PoP installation. The top package of the A4 used in the iPad, in the iPod Touch[15] 4th gen and in the Apple TV[16] 2nd gen contains two low-power 128 MB DDR SDRAM chips for a total of 256MB RAM. For the iPhone 4 there are two chips of 256 MB for a total of 512 MB.[17][18][19] RAM is connected to the processor using ARM's 64-bit-wide AMBA 3 AXI bus. This is twice the width of the RAM data bus used in previous ARM 11 and ARM 9 based Apple devices, to support the greater need for graphics bandwidth in the iPad.[20]

History

The A4 was announced (together with the iPad) on January 27, 2010, during Apple's "Latest Creation" event.[3]

On June 7, 2010, Steve Jobs publicly confirmed that the iPhone 4 will contain the A4 Processor, although it is not yet known if it has the same frequency, bus width, or caches as the A4 found in the earlier produced iPad.[4]

On September 1, 2010, the iPod Touch and Apple TV were updated to include the A4 Processor.

Products that include the Apple A4

See also

References

  1. ^ Clark, Don (2010-04-05). "Apple iPad Taps Familiar Component Suppliers - WSJ.com". Online.wsj.com. Retrieved 2010-04-15.
  2. ^ "iPad - It's thin, light, powerful, and revolutionary". Apple. Retrieved 2010-07-07.
  3. ^ a b c "Apple Launches iPad" (Press release). Apple. 2010-01-27. Retrieved 2010-01-28.
  4. ^ a b "iPhone 4 design". Apple. 2010-07-06.
  5. ^ Vance, Ashlee (2010-02-21). "For Chip Makers, the Next Battle Is in Smartphones". New York Times. Retrieved 2010-02-25.
  6. ^ Wiens, Kyle (2010-04-05). "conclusion from both hard and software analysis it uses an ARM Cortex-A8 core". Ifixit.com. Retrieved 2010-04-15.
  7. ^ "iPad — Technical specifications and accessories for iPad". Apple. Retrieved 2010-01-28.
  8. ^ Melanson, Donald (2010-02-23). "iPad confirmed to use PowerVR SGX graphics". Engadget.
  9. ^ "Chipworks Confirms Apple A4 iPad chip is fabbed by Samsung in their 45-nm process". Chipworks.
  10. ^ Stokes, Jon (2010-04-28). "Apple purchase of Intrinsity confirmed". Ars Technica. Retrieved 2010-04-28.
  11. ^ Merritt, Rick. "Samsung, Intrinsity pump ARM to GHz rate". EETimes.com. Retrieved 2010-04-23.
  12. ^ Keizer, Gregg (2010-04-06). "Apple iPad smokes past the iPhone 3GS in speed". PC World. Retrieved 2010-04-11.
  13. ^ Boldt, Paul; Scansen, Don; Whibley, Tim (16 June 2010). "Apple's A4 dissected, discussed...and tantalizing". EETimes.com. Retrieved 2010-07-07.
  14. ^ "Microsoft PowerPoint - Apple A4 vs SEC S5PC110A01" (PDF). Retrieved 2010-07-07.
  15. ^ "Teardown of Apple's 4th-gen iPod touch finds 256MB of RAM". Appleinsider.com. 2010-09-08. Retrieved 2010-09-10.
  16. ^ "Apple TV 2nd Generation Teardown". iFixit. 2010-09-30. Retrieved 2011-01-04.
  17. ^ "Apple reveals iPhone 4 has 512MB RAM, doubling iPad - report". Appleinsider.com. 2010-06-17. Retrieved 2010-07-07.
  18. ^ "A Peek Inside Apple's A4 Processor". iFixit. 2010-04-05.
  19. ^ Greenberg, Marc (2010-04-09). "Apple iPad: no LPDDR2?". Denali.
  20. ^ Merritt, Rick (2010-04-09). "iPad equipped to deliver richer graphics". EE Times Asia. Retrieved 2010-04-14.


External links

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