The Apple A4 is a 32-bit

package on package Package on a package (PoP) is an integrated circuit packaging method to vertically combine ball grid array (BGA) packages for discrete logic and Semiconductor memory, memory. Two or more packages are installed atop each other, i.e. stacked, with a ...

(PoP)

system on a chip A system on a chip (SoC) is an integrated circuit that combines most or all key components of a computer or Electronics, electronic system onto a single microchip. Typically, an SoC includes a central processing unit (CPU) with computer memory, ...

(SoC) designed by

Apple Inc. Apple Inc. is an American multinational corporation and technology company headquartered in Cupertino, California, in Silicon Valley. It is best known for its consumer electronics, software, and services. Founded in 1976 as Apple Comput ...

, part of the

Apple silicon Apple silicon is a series of system on a chip (SoC) and system in a package (SiP) processors designed by Apple Inc., mainly using the ARM architecture family, ARM architecture. They are used in nearly all of the company's devices including Mac ...

series, and manufactured by

Samsung Samsung Group (; stylised as SΛMSUNG) is a South Korean Multinational corporation, multinational manufacturing Conglomerate (company), conglomerate headquartered in the Samsung Town office complex in Seoul. The group consists of numerous a ...

. It was the first SoC Apple designed in-house. The first product to feature the A4 was the first-generation iPad, followed by the

iPhone 4 The iPhone 4 is a smartphone that was developed and marketed by Apple Inc. It is the List of iPhone models, fourth generation of the iPhone lineup, succeeding the iPhone 3GS and preceding the iPhone 4s. Following a number of notable leaks, ...

, fourth-generation iPod Touch, and second-generation Apple TV. The last operating system update Apple provided for a mobile device containing an A4 (

) was iOS 7.1.2, which was released on June 30, 2014 as it was discontinued with the release of

iOS 8 iOS 8 is the eighth major release of the iOS mobile operating system developed by Apple Inc., being the successor to iOS 7. It was announced at the company's Worldwide Developers Conference on June 2, 2014, and was released on September 17 ...

in September 2014. The

iPad (1st generation) The first-generation iPad (; ) (retrospectively referred to unofficially as the iPad 1 or original iPad) is a tablet computer designed and marketed by Apple Inc. as the first device in the iPad lineup of tablet computers. It features an Appl ...

was discontinued earlier than the iPhone 4 with the release of iOS 5.1.1 on May 7, 2012 because it only had 256 MB of RAM compared to 512 MB on the iPhone, and the fact that applications would crash more frequently with the graphics using a large portion of the RAM. The last operating system update Apple provided for an Apple TV containing an A4 ( second-generation Apple TV) was Apple TV Software 6.2.1, which was released on September 17, 2014. History of glass

Design

Apple engineers designed the A4 chip with an emphasis on being "extremely powerful yet extremely power efficient." The A4 features a single-core

ARM Cortex-A8 The ARM Cortex-A8 is a 32-bit processor core licensed by ARM Holdings implementing the ARM architecture, ARMv7-A architecture. Compared to the ARM11, the Cortex-A8 is a dual-issue superscalar processor, superscalar design, achieving roughly twic ...

central processing unit A central processing unit (CPU), also called a central processor, main processor, or just processor, is the primary Processor (computing), processor in a given computer. Its electronic circuitry executes Instruction (computing), instructions ...

(CPU) manufactured on Samsung's 45 nm fabrication process using performance enhancements developed by chip designer

Intrinsity Intrinsity, Inc. was a privately held Austin, Texas based fabless semiconductor company; it was founded in 1997 as EVSX on the remnants of Exponential Technology and changed its name to Intrinsity in 2000. It had around 100 employees and supplied ...

(which was subsequently acquired by Apple) in collaboration with

. The resulting CPU, dubbed "

Hummingbird Hummingbirds are birds native to the Americas and comprise the Family (biology), biological family Trochilidae. With approximately 366 species and 113 genus, genera, they occur from Alaska to Tierra del Fuego, but most species are found in Cen ...

", 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 by ARM. The same Cortex-A8 used in the A4 is also used in Samsung's S5PC110A01 SoC. The A4 also features a single-core PowerVR SGX535

graphics processing unit A graphics processing unit (GPU) is a specialized electronic circuit designed for digital image processing and to accelerate computer graphics, being present either as a discrete video card or embedded on motherboards, mobile phones, personal ...

(GPU). The die of the A4 takes up 53.3 mm² of area. The

clock rate Clock rate or clock speed in computing typically refers to the frequency at which the clock generator of a processor can generate pulses used to synchronize the operations of its components. It is used as an indicator of the processor's s ...

of the Cortex-A8 in the A4 used inside the first-generation iPad is 1

GHz The hertz (symbol: Hz) is the unit of frequency in the International System of Units (SI), often described as being equivalent to one event (or Cycle per second, cycle) per second. The hertz is an SI derived unit whose formal expression in ter ...

. The clock rate of the Cortex-A8 in the A4 used inside the

and fourth-generation iPod Touch is 800 MHz (

underclocked Underclocking, also known as downclocking, is modifying a computer or electronic circuit's timing settings to run at a lower clock rate than is specified. Underclocking is used to reduce a computer's power consumption, increase battery life, redu ...

from 1 GHz). It is unknown what the clock rate of the Cortex-A8 in the A4 used inside the second-generation Apple TV is. The A4 uses the PoP 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 MB LPDDR chips, providing a total of 256 MB of RAM. 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. The RAM is connected to the A4 using ARM's 64 bits wide AMBA 3 AXI

bus A bus (contracted from omnibus, with variants multibus, motorbus, autobus, etc.) is a motor vehicle that carries significantly more passengers than an average car or van, but fewer than the average rail transport. It is most commonly used ...

Products featuring the Apple A4

iPod Touch (4th generation) The fourth generation iPod Touch (marketed as "the new iPod touch", and colloquially known as the iPod Touch 4G, iPod Touch 4, or iPod 4) is a multi-touch mobile device designed and marketed by Apple Inc. with a touchscreen-based user interfac ...

* Apple TV (2nd generation)

Gallery

References

External links

MacWorld – Apple inside: the significance of the iPad's A4 chip
* CNET�
Inside the iPad: Apple's new 'A4' chip
* HotHardware�
iPad's Identity Crisis and Apple's A4 CPU Showstopper
* EETimes�
Apple's A4 dissected

Understanding iPad’s A4 Processor

ARM Cortex-A series processors

PowerVR GPU specifications pages
{{Application ARM-based chips Products introduced in 2010 Products and services discontinued in 2014 Apple silicon

Design

Products featuring the Apple A4

Gallery

See also

References

External links