Apple A4

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Apple A4
Apple A4 Chip.jpg
Produced From April 3, 2010 to September 10, 2013
Designed by Apple Inc.
Common manufacturer(s)
Max. CPU clock rate 800 MHz (iPhone 4, iPod touch 4G)  to 1 GHz (iPad) 
Min. feature size 45 nm
Microarchitecture ARM Cortex-A8
Product code S5L8930X[1]
Cores 1
L1 cache 32 KB instruction + 32 KB data[2]
L2 cache 512 KB[2]
Predecessor Samsung S5L8922
Successor Apple A5
GPU PowerVR SGX 535[3]
Application Mobile

The Apple A4 is a 32-bit package on package (PoP) system-on-a-chip (SoC) designed by Apple Inc. and manufactured by Samsung.[4] It combines an ARM Cortex-A8 CPU with a PowerVR GPU, and emphasizes power efficiency.[5] The chip commercially debuted with the release of Apple's iPad tablet;[6] followed shortly by the iPhone 4 smartphone,[7] the iPod Touch (4th generation), and the Apple TV (2nd generation). It was superseded by the Apple A5 processor used in the iPad 2 released the following year, which was then subsequently replaced by the Apple A5X processor in the iPad (3rd generation).

Design

Apple A4 is based on the ARM processor architecture.[8] 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)[6][9][10][11] built on Samsung's 45 nm silicon chip fabrication process.[12] The clock speed for the units used in the iPhone 4 and iPod Touch (4th generation) is 800 MHz, but the clock speed for the unit used in the Apple TV has not been released.

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)[13] in collaboration with Samsung.[14] 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.[15] 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.[16][17]

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[18] 4th gen and in the Apple TV[19] 2nd gen contains two low-power 128 MB DDR SDRAM chips for a total of 256 MB RAM. For the iPhone 4 there are two chips of 256 MB for a total of 512 MB.[20][21][22] RAM is connected to the processor using ARM's 64-bit-wide AMBA 3 AXI bus. This is twice the width of the memory buses of the SoCs used by the contemporary Apple iPhone and iPod touch, supporting the greater need for graphics bandwidth in the iPad.[23]

History

The Apple A4 chip, along with the original iPad, was announced on January 27, 2010, during Apple's "Latest Creation" event.[6]

On June 7, 2010, Steve Jobs publicly confirmed that the iPhone 4 would contain the A4 processor, although it was not yet known at the time if it would have the same frequency, bus width, or caches as the A4 found in the earlier produced iPad.[7]

On September 1, 2010, the iPod Touch (4th generation), and the Apple TV (2nd generation) were updated to include the A4 processor. Later, on October 4, 2011, Apple refreshed the iPod Touch (4th generation) to add a white model, along with the existing black model. Both models still contain the A4 processor.[24]

Products that include the Apple A4

  • iPad: April 2010
  • iPhone 4: June 2010 (Black; GSM), February 2011 (Black; CDMA), April 2011 (White; GSM & CDMA models)
  • iPod Touch (4th generation): September 2010 (Black model), October 2011 (White model)
  • Apple TV (2nd generation): September 2010

See also

References

  1. ↑ iOS 5.1 code hints at simultaneous A5X and A6 processor development
  2. ↑ 2.0 2.1 Lua error in package.lua at line 80: module 'strict' not found.
  3. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  4. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  5. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  6. ↑ 6.0 6.1 6.2 Lua error in package.lua at line 80: module 'strict' not found.
  7. ↑ 7.0 7.1 Lua error in package.lua at line 80: module 'strict' not found.
  8. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  9. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  10. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  11. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  12. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  13. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  14. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  15. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  16. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  17. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  18. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  19. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  20. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  21. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  22. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  23. ↑ Lua error in package.lua at line 80: module 'strict' not found.
  24. ↑ https://www.apple.com/ipodtouch/specs.html

External links

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