Apple A4 Apple mobile application processors

the apple a4 package on package (pop) system on chip (soc) designed apple inc. , manufactured samsung. combines arm cortex-a8 cpu powervr gpu, , emphasizes power efficiency. chip commercially debuted release of apple s ipad tablet; followed shortly iphone 4 smartphone, 4th generation ipod touch , 2nd generation apple tv. superseded in ipad 2, released following year, apple a5 processor.

apple a4 based on arm processor architecture. first version released ran @ 1 ghz ipad , contains arm cortex-a8 cpu core paired powervr sgx 535 graphics processor (gpu) built on samsung s 45-nanometer (nm) silicon chip fabrication process. clock speed units used in iphone 4 , ipod touch (4th generation) 800 mhz. clock speed unit used in apple tv has not been revealed.

the cortex-a8 core used in a4 thought use performance enhancements developed chip designer intrinsity (which subsequently acquired apple) in collaboration samsung. resulting core, dubbed hummingbird , able run @ far higher clock rates other implementations while remaining compatible cortex-a8 design provided arm. other performance improvements include additional l2 cache. same cortex-a8 cpu core used in a4 used in samsung s s5pc110a01 soc. sgx535 in a4 theoretically push 35 million polygons/second , 500 million pixels/second, although real world performance may considerably less.

the a4 processor package not contain ram, supports pop installation. hence, there package 2 low-power 128 mb ddr sdram chips (totaling 256 mb) mounted on top of a4 used in first-generation ipad, fourth-generation ipod touch, , second-generation apple tv. iphone 4 has 2 256 mb packages total of 512 mb. ram connected processor using arm s 64-bit-wide amba 3 axi bus. support ipad s demand high graphics bandwidth, width of ram data bus double used in previous arm11 , arm9 based apple devices.