A Closer Look at the Stars of Apple Event 2021: The A15 Bionic and iPhone13

September 20, 2021 by Adrian Gibbons

At this year's Apple Event 2021, the company announced details about the newest Apple A-series cellular SoC—the A15 Bionic—and the iPhone13.

Last week Apple held the Apple Event 2021, where it released details on its newest product lineup, including the next-generation iPhone13. The iPhone13 contains the latest A-series chipset, the A15 Bionic.


The new iPhone13 Mini (left) and iPhone13 (right)

The new iPhone13 Mini (left) and iPhone13 (right). Image used courtesy of Apple


What's notable about these announcements from a hardware perspective? To answer this question, it's important to look specifically at the revealed A15 Bionic chipset specifications. We'll also further analyze the development of the A15 by looking at past A-series generations and sizing this chip up against competing smartphone processors. 


A Look Inside the 2021 iPhone13

A peeled-back view of the phone system during the Apple Event broadcast reveals a tightly-packed hardware system. The battery is the most prominent feature on the surface of revealed iPhone hardware. 


Inside the iPhone13 (2021)

Inside the 2021 iPhone13. Screenshot used courtesy of Apple


The iPhone13 is said to have between 1.5 to 2.5 (model dependent) additional hours of life when compared to the iPhone12 due to a larger battery and “improved” software/hardware integration. 

Longer battery life is critical to user satisfaction—but for designers, what are the hardware advancements?


A15 Bionic Hardware: What We Know

Apple, as usual, is tightlipped with its hardware details. However, the Apple Event last week did provide designers with some basic specifications, lending the opportunity to read between the lines to some degree.

The SoC is based on TSMC’s 5nm process node (as was the A14 Bionic last year) and has increased transistor density by ~27.12% or 3.2 billion transistors over the A14. Overall performance improvements for the CPU and GPU are said to be 50 percent and 30 percent faster than the competition, respectively. 

The new chip utilizes the same core count (six total) as the A14, a 2/4 split of performance and efficiency CPU cores, along with a 16-core neural processor unit (NPU) and a 4-core GPU. The NPU is rated to perform 15.8 trillion operations per second, an increase of 43.64 percent over the A14 Bionic. 


Promotional specifications

Promotional specifications for the A15 Bionic chipset. Screenshot used courtesy of Apple


The TrueDepth front camera system area has been shrunk by 20 percent, providing for more screen real estate. This might possibly indicate an increased PCB design density in that area. Along with a larger battery and the redesigned rear camera system, the iPhone13 is a densely packed piece of hardware.

So, how do the changes from A14 to A15 really stack up against the competition? 

“Frankly, the competition is still playing catch up to our chips, not just from last year but even from two years ago,” says Kaiann Drance, Apple's VP of iPhone product marketing. 


Looking Forward By Examining Previous Generations of iPhone A-Series

Benchmarks certainly favor the iPhone13, showing improvements over the iPhone12’s A14 Bionic chipset. This is the second A-series chip using TSMC’s 5nm foundry.

The A13 (2019) had 8.5 billion transistors and was fabricated on TSMC’s N7P process. It replaced the A12 (TSMC N7) with better performance and power efficiency, but with a cost. The 23 percent increase in transistor count incurred an ~18 percent increase in die area (from 83 mm square to 98 mm square).

Now, the N5 process was able to reduce the A14 die size to ~88 mm square. The problem with N5 is that SRAM is not scaling as well as logic, and in the A15, Apple has doubled the system cache. 

All of this is to say, Apple may be backing itself into a corner in terms of maxing out the performance. The increasing densification of the iPhone13 hardware system might not leave enough room to push the die size of the A-series chips much. 

A teardown of the iPhone11 Pro Max (A13) below, courtesy of Tech Insights, shows just how tightly packed modern cell phones are. 


Teardown of an iPhone11 Pro Max

Teardown of an iPhone11 Pro Max (A13) shows highly constrained hardware. Image used courtesy of Tech Insights


Is Kaiann Drance correct? Is everyone else playing catch-up? Perhaps. 

Samsung and Qualcomm are both a half-year into their current generation technology, while Apple has just released theirs. Maybe this will give the competition time to catch up.


Are Google, Samsung, and Qualcomm Still in the Race? 

The N5 is now the industry standard for this grade of technology. As we can see below, all current-gen cellular SoCs are fabricated on this node size. Recently, Google decided to get on board with the Tensor.

SoC for SoC, we can see that all industry players are interfacing multi-core CPU architectures with embedded GPU capability and onboard ML processors.


Comparison chart for three current-generation cellular SoCs

Comparison chart for three current-generation cellular SoCs. Image used courtesy Android Authority


However, the hardware itself is only one side of the equation. Apple touts software/hardware integration as a major selling feature for the performance of the iPhone13. 

The camera system in the iPhone13 received a significant amount of focus, mostly because it acts as the eyes for the ML capabilities of the phone. The new Cinematic Mode and Live Text with iOS 15 are two key examples of this integration. 

An AI-enhanced camera system focused on delivering professional grade film and photography capability positions the iPhone13 not only as a device for consumers but also for migration into a professional’s toolkit.