 | |
| General information | |
|---|---|
| Launched | April 3, 2010 |
| Discontinued | September 10, 2013 |
| Designed by | Apple Inc. |
| Common manufacturer | |
| Product code | S5L8930X[1] |
| Performance | |
| Max.CPUclock rate | 800 MHz to 1 GHz |
| Physical specifications | |
| Cores |
|
| GPU | PowerVR SGX535[2] |
| Cache | |
| L1cache | 32 KB instruction + 32 KB data[3] |
| L2 cache | 512 KB[3] |
| Architecture and classification | |
| Application | Mobile |
| Technology node | 45 nm |
| Microarchitecture | ARM Cortex-A8 |
| Instruction set | ARMv7-A |
| History | |
| Predecessor | Samsung S5L8920 |
| Successors | Apple A5 (iPhone) Apple A5X (iPad) |
TheApple A4 is a 32-bitpackage on package (PoP)system on a chip (SoC) designed byApple Inc., part of theApple silicon series, and manufactured bySamsung.[4][5] The A4 was the first SoC Apple designed in-house, as the processors for the first 3iPhone models were designed by Samsung instead. The first product to feature the A4 was thefirst-generation iPad, followed by theiPhone 4,fourth-generation iPod Touch, andsecond-generation Apple TV.[6]
The last operating system update Apple provided for a mobile device containing an A4 (that being theiPhone 4) wasiOS 7.1.2, which was released on June 30, 2014 as it was discontinued with the release ofiOS 8 in September 2014. TheiPad (1st generation) andfourth generation iPod Touch were discontinued earlier than the iPhone 4, with the former last receivingiOS 5.1.1 on May 7, 2012 and the latter last receivingiOS 6.1.6 on February 21, 2014, despite the latter’s variant of the A4 having a slower CPU clock speed. The last operating system update Apple provided for an Apple TV containing an A4 (that being thesecond-generation Apple TV) wasApple TV Software 6.2.1, which was released on September 17, 2014.
Apple engineers designed the A4 chip with an emphasis on being "extremely powerful yet extremely power efficient."[6] The A4 features a single-coreARM Cortex-A8central processing unit (CPU) manufactured on Samsung's 45nm fabrication process[7] using performance enhancements developed by chip designerIntrinsity (which was subsequently acquired by Apple)[8] in collaboration withSamsung.[9] The resulting CPU, dubbed "Hummingbird",[10] is able to run at a far higher clock rate than previous Cortex-A8 CPUs while remaining fully compatible with the Cortex-A8 design provided byARM.[11] The same Cortex-A8 used in the A4 is also used in Samsung's S5PC110A01 SoC.[12][13] The A4 also features a single-corePowerVR SGX535graphics processing unit (GPU).[14] The die of the A4 takes up 53.3 mm2 of area.[15]
Theclock rate of the Cortex-A8 in the A4 used inside thefirst-generation iPad is 1GHz. The clock rate of the Cortex-A8 in the A4 used inside theiPhone 4 andfourth-generation iPod Touch is 800 MHz (underclocked from 1 GHz). It is unknown what the clock rate of the Cortex-A8 in the A4 used inside thesecond-generation Apple TV is.
The A4 uses thePoP method of installation to support RAM. The top package of the A4 used inside the first-generation iPad, the fourth-generation iPod Touch, and the second-generation Apple TV contains two 128 MBLPDDR chips, providing a total of 256 MB of RAM.[16][17] The top package of the A4 used inside the iPhone 4 contains two 256 MB LPDDR chips, providing a total of 512 MB of RAM.[18][19] The RAM is connected to the A4 using ARM's 64 bits wideAMBA 3 AXIbus.[20]
The company conducted a cross-section analysis of the chip that revealed details indicating Samsung made the chip in its 45nm process, the same process and fab Apple used for its previous generation A4 SoC.
The die was approximately 7.3 mm square, giving a die area of 53.3 mm2,