The Apple A4 is a 32-bit

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

(PoP)

system on a chip A system on a chip or system-on-chip (SoC ; pl. ''SoCs'' ) is an integrated circuit that integrates most or all components of a computer or other electronic system. These components almost always include a central processing unit (CPU), memory ...

(SoC) designed by

Apple Inc. Apple Inc. is an American multinational technology company headquartered in Cupertino, California, United States. Apple is the largest technology company by revenue (totaling in 2021) and, as of June 2022, is the world's biggest company ...

and manufactured by

Samsung The Samsung Group (or simply Samsung) ( ko, 삼성 ) is a South Korean multinational manufacturing conglomerate headquartered in Samsung Town, Seoul, South Korea. It comprises numerous affiliated businesses, most of them united under the ...

. 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 designed and marketed by Apple Inc. It is the fourth generation of the iPhone lineup, succeeding the iPhone 3GS and preceding the 4S. Following a number of notable leaks, the iPhone 4 was first unvei ...

, 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 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.

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 ARMv7-A architecture. Compared to the ARM11, the Cortex-A8 is a dual-issue superscalar design, achieving roughly twice the instructions per cycle. The Cort ...

central processing unit A central processing unit (CPU), also called a central processor, main processor or just processor, is the electronic circuitry that executes instructions comprising a computer program. The CPU performs basic arithmetic, logic, controlling, an ...

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

Intrinsity Intrinsity 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 too ...

(which was subsequently acquired by Apple) in collaboration with

. The resulting CPU, dubbed "

Hummingbird Hummingbirds are birds native to the Americas and comprise the biological family Trochilidae. With about 361 species and 113 genera, they occur from Alaska to Tierra del Fuego, but the vast majority of the species are found in the tropics aro ...

", 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 In human anatomy, the arm refers to the upper limb in common usage, although academically the term specifically means the upper arm between the glenohumeral joint (shoulder joint) and the elbow joint. The distal part of the upper limb between th ...

. 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 to manipulate and alter memory to accelerate the creation of images in a frame buffer intended for output to a display device. GPUs are used in embedded systems, mobi ...

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

clock rate In computing, the clock rate or clock speed typically refers to the frequency at which the clock generator of a processor can generate pulses, which are used to synchronize the operations of its components, and is used as an indicator of the pr ...

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), equivalent to one event (or cycle) per second. The hertz is an SI derived unit whose expression in terms of SI base units is s−1, meaning that one he ...

. 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 Low-Power Double Data Rate (LPDDR), also known as LPDDR SDRAM, is a type of synchronous dynamic random-access memory that consumes less power and is targeted for mobile computers and devices such as mobile phones. Older variants are also known as ...

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 road vehicle that carries significantly more passengers than an average car or van. It is most commonly used in public transport, but is also in use for cha ...

Products featuring the Apple A4

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. The device features ...

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 interfa ...

Apple TV (2nd generation) Apple TV is a digital media player and microconsole developed and marketed by Apple Inc. It is a small networking hardware, network appliance hardware that plays received media data such as video and audio to a television set or external displ ...

Gallery

References

External links

MacWorld – Apple inside: the significance of the iPad's A4 chip
*

CNET ''CNET'' (short for "Computer Network") is an American media website that publishes reviews, news, articles, blogs, podcasts, and videos on technology and consumer electronics globally. ''CNET'' originally produced content for radio and televi ...

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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