Apple Watch battery life, A5-caliber CPU inside

Apple watch battery life is a key factor in how useful this new computer interface will be in our lives. Some information is discussed in the article below. 

"Apple opted to use a relatively powerful processor and high-quality screen for the Apple Watch, both of which contribute to significant power drain. Running a stripped-down version of iOS codenamed SkiHill, the Apple S1 chip inside the Apple Watch is surprisingly close in performance to the version of Apple's A5 processor found inside the current-generation iPod touch,"

More about A5 power consumption is in May 2012 article Apple's A5 Die Shrink, Improve Battery Life, Cut Cost .

 Ron

Insightful, timely, and accurate semiconductor consulting.
Semiconductor information and news at - http://www.maltiel-consulting.com/

Apple targets for Apple Watch battery life revealed, A5-caliber CPU inside

Although Apple has said that the Apple Watch will need to be charged nightly, the company has not disclosed any details on how long the wearable's battery will last. For the first time, people with knowledge of the Apple Watch's development have provided us with the specific performance targets Apple wants to achieve for the Apple Watch battery, but the actual numbers may fall short of those targets.

According to our sources, Apple opted to use a relatively powerful processor and high-quality screen for the Apple Watch, both of which contribute to significant power drain. Running a stripped-down version of iOS codenamed SkiHill, the Apple S1 chip inside the Apple Watch is surprisingly close in performance to the version of Apple's A5 processor found inside the current-generation iPod touch, while the Retina-class color display is capable of updating at a fluid 60 frames per second.

Apple initially wanted the Apple Watch battery to provide roughly one full day of usage, mixing a comparatively small amount of active use with a larger amount of passive use. As of 2014, Apple wanted the Watch to provide roughly 2.5 to 4 hours of active application use versus 19 hours of combined active/passive use, 3 days of pure standby time, or 4 days if left in a sleeping mode. Sources, however, say that Apple will only likely achieve approximately 2-3 days in either the standby or low-power modes…

Apple has also been stress-testing the Apple Watch's battery life with pre-bundled and third-party applications. Our sources say that Apple is targeting 2.5 hours of "heavy" application use, such as processor-intensive gameplay, or 3.5 hours of standard app use. Interestingly, Apple expects to see better battery life when using the Watch's fitness tracking software, which is targeted for nearly 4 hours of straight exercise tracking on a single charge.

As Apple is positioning the Apple Watch as a timepiece, the company has conducted numerous tests to determine how long it can run purely in time-keeping modes. We're told that the Watch should be able to display its clock face for approximately three hours, including watch ticking animations, if nothing else is done with the device. However, it's unlikely that most people would actually keep the Apple Watch clock face turned on for even three hours straight in a single day. When the Watch screen is not in use, the display is powered off, and the clock demands much less energy.

Considered separately, the active use app, clock, and fitness numbers sound very low, but the reality is that people will passively wear the Apple Watch for most of the day, actively interacting with it only for short periods of time. That's why the Watch will be able to last the average user roughly a day on a single charge. We're told that Apple has been shooting for roughly 19 hours of mixed usage each day, but that the company may not hit that number in the first generation version.

Sources tell us that battery life has remained a source of concern for Apple over the past year, and was a contributing factor for Apple pushing back the retail launch from an originally planned late 2014 to early 2015. To test real-world performance in a variety of conditions, the company has circulated a surprisingly large number of test units of the Watch: nearly 3,000 are said to be currently roaming around, mostly the stainless steel variant.

Apple has also been working to perfect the MagSafe-based inductive charging mechanism for the Watch, which sources indicate was responsible for slower-than-expected recharging times that hopefully will be fixed in time for the product's release. The company has developed both plastic and stainless steel versions of the circular charger, potentially one for the $349 aluminum and plastic Apple Watch Sport, and the other for the higher-end models. It's unclear at this point whether the company will sell multiple versions of the charger, as Apple has only shown the metal variant, though the Apple Watch Edition is said to ship with a special box and charging dock that may incorporate the stainless steel MagSafe connector.

As of earlier this month, the Apple Watch is on track to ship by the end of March. We previously detailed how the Watch will integrate with the iPhone via an iOS 8.2-based Companion application.

Apple iPad 4 – A6X Tear-down

Chipwork's teardown of the new Apple iPad 4 reveals a major redesign of the graphic processor (GPU). The much larger area dedicated to the GPU and wider interface of the DRAM improves the display and touch screen performance of the iPad 4. It probably also helps prolong battery life.


" The A6 is 94mm2 while the A6X is 123mm2 – a full 30% larger.So where did that extra area go? Well, firstly, it did not go to the CPU core. The A6X uses the identical CPU to the A6. Same size, same layout. This is not surprising given that the prior CPU used custom layout techniques, and therefore it would be a huge amount of work to redesign so soon. Much of the extra area has gone to the GPU cores which are up from 3 to 4. More notable is that each of these GPU cores is much larger.On the A6X each GPU core is 8.7mm2 while the A6 GPU cores are only 5.4mm2. The overall area occupied by the A6X GPU cores is more than double that of the A6!

So we see that of the 29 mm2 of new area on the A6X, a full 18.6 mm2 is the result of the increased quantity of graphics processing. Impressive!

Additionally, if you look closely at the GPU cores (which our high magnification scopes allow us to do), we can see they are actually split into sub-cores themselves. Each GPU core is sub-divided into 9 sub-cores (2 sets of 4 identical sub-cores plus a central core). This could be done to allow for more efficient parallel processing, or to allow for a higher maximum clock rate. In either case, these GPUs should result in some blazing graphics on your iPad.

Other items of note:

It looks like the A6X has double the SDRAM interface width of the A6 (again likely to allow for greater graphics processing power).

Other than the CPU, it appears all the other digital cores have new layouts. This chip is not just a minor tweak from the A6, a lot of work has gone into this.

Apple has reduced the number of core PLLs needed from 9 on the A6 to 8 on the A6X. However they have moved them close to the middle of the chip which may allow for better control over clock skew across the chip.

Many of the analog and interface cores have been reused from the A6, however there are also some new interface blocks."

Additional information

Ron Maltiel   www.maltiel-consulting.com

Apple's A6X Processor 32nm Process Advantages

Apple's latest iPad 4 processor comes with its latest processor: an A6X, which Apple says delivers twice the CPU and graphics performance as the A5X. See below some details about Apple's A6X processor.

"Apple moved from a 45nm process to a more power-efficient 32nm process. Instead of keeping performance the same and decreasing the iPad's thickness and weight, Apple instead chose to double its performance without sacrificing all-day battery life."

More about Apple's optimizing process and design at iPhone A6 Teardown Update

Ron
http://www.maltiel-consulting.com/






Deducing details about Apple's A6X processor


Apple promises double the CPU and graphics performance over the A5X, but how?

by Chris Foresman - Oct 23 2012, 3:25pm PDT


As usual, Apple didn't share many specifics about its new A6 "Extreme" (A6X) processor, which powers the fourth-generation iPad. However, by looking at Apple's claims that it's "twice as fast" as the A5X-powered third-gen iPad, it may be possible to deduce what's inside.

According to Apple, the A6X processor "delivers up to twice the CPU and graphics performance of the A5X chip." In other words, the dual-core CPU can process data twice as fast as the dual-core 1GHz, Cortex A9-based A5X. It can also churn through OpenGL triangles and textures at twice the rate of the PowerVR SGX543MP4 in the A5X. So how did Apple do that?

Looking at CPU power for the moment, we already know that Apple designed a custom ARM-based core for the A6. Running at 1.2GHz in the iPhone 5, two A6 cores run twice as fast as two 800MHz A5 cores in an iPhone 4S.

However, the A5X in the third-gen iPad was clocked at 1GHz. That means Apple is clocking the A6X higher yet. Given that architectural improvements account for some of the speed increase, Apple only had to clock the iPhone 5 at 150 percent to achieve double the compute performance of the iPhone 4S. With this in mind, we believe Apple is clocking the A6X's CPU cores at 1.5GHz.

Examining the GPU is slightly different. Apple already jammed four SGX543 GPU cores into the A5X in order to achieve performance parity with the two SGX543 GPU cores in the A5 chip that powers the iPad 2. The extra GPUs were needed just to keep up with the 2048×1532 pixel Retina display, so these did not offer any graphics performance improvement. However, Apple says that the A6X pumps pixels twice as fast.

Apple could be using a newer-generation PowerVR core, but that appears to be very unlikely. Only one announced processor is known to use a PowerVR Series6 design, and it won't even begin sampling until 2013. Given that Apple just released the A6 a month ago, we're confident Apple is still using the same SGX543 core.

Here's what we know about the PowerVR SGX543 core's performance: it scales almost linearly with the number of cores and clock speed. So to double the performance, Apple would either have to double the number of cores to eight or double the clock speed of each of the four cores. Apple says that the A6X has "quad-core graphics"—the same as the A5X—so Apple clearly boosted the clock speed. Since the GPUs in the A5X were clocked at 250MHz, we believe that Apple has clocked the SGX543 cores at 500MHz.

Given the significant boosts in clock frequency—150 percent for the CPU cores, and 200 percent for the GPU cores—you may be wondering how Apple can still promise a 10-hour battery life. After all, the iPad still has the exact same 42.5Whr battery, but the processor is twice as powerful. The power savings come from the same place as we saw in the iPhone—Apple moved from a 45nm process to a more power-efficient 32nm process. Instead of keeping performance the same and decreasing the iPad's thickness and weight, Apple instead chose to double its performance without sacrificing all-day battery life.

Of course, we won't know how accurate our educated guesses are until one of the new iPads can be thoroughly benched, and the A6X's architecture is analyzed by the likes of Chipworks. However, we feel confident suggesting Apple has mated two A6 ARM cores running at 1.5GHz with four PowerVR SGX543 cores running at 500MHz. Given the performance results we saw with the iPhone 5, we expect the updated iPad will remain at the top of the tablet performance heap for some time.

Apple's A5 Die Shrink, Improve Battery Life, Cut Cost

A teardown of a new iPad reveals a shrunk SoC die (see below). In second  half of 2011 an iPad's processor was made in the 45nm manufacturing process, while the current iPad seems to use a 32nm process.

The new 32nm A5 has a chip die area of only 69mm2 while in the 45nm process it was more than 120mm2 . I predicted that Apple will shift soon to 32nm process to improve battery life on March 22 in my blog post  New iPad-Teardown: Why Apple's A5X uses 45nm



This shrink will substantially reduce the cost of the A5 for Apple as Samsung improve the die yield of its  32nm high-k + metal gate LP manufacturing process.

Ron Maltiel

The iPad 2,4 Review: 32nm Brings Better Battery Life


by Anand Lal Shimpi on 5/4/2012 12:50:00 AM
http://www.anandtech.com/show/5789/the-ipad-24-review-32nm-a5-tested

When Apple launched the 3rd generation iPad (as the new iPad), it also dropped the price of the entry-level 16GB WiFi iPad 2 to $399. Apple's products tend to hold their values exceptionally well, so this two-tablet strategy made sense. Apple also proved the success of discount-the-previous-gen strategy with its iPhone line, where you can now buy current, n-1 and n-2 generations of iPhones at prices separated by $100.

What's different with the $399 iPad 2 is that Apple used it as a vehicle to introduce a new hardware platform, or more specifically, a new SoC.


When Apple launched the 3rd generation iPad (as the new iPad), it also dropped the price of the entry-level 16GB WiFi iPad 2 to $399. Apple's products tend to hold their values exceptionally well, so this two-tablet strategy made sense. Apple also proved the success of discount-the-previous-gen strategy with its iPhone line, where you can now buy current, n-1 and n-2 generations of iPhones at prices separated by $100.

What's different with the $399 iPad 2 is that Apple used it as a vehicle to introduce a new hardware platform, or more specifically, a new SoC.



The 32nm HK+MG Apple A5 SoC

Prior to the new iPad announcement there were three versions of the iPad 2:



iPad 2,1 iPad 2,2 iPad 2,3 iPad 2,4

A5 SoC 45nm LP 45nm LP 45nm LP 32nm LP

Connectivity WiFi WiFi + GSM WiFi + CDMA WiFi


Connectivity WiFi WiFi + GSM WiFi + CDMA WiFi
The 2,1 was WiFi-only, the 2,2 was GSM and the 2,3 was CDMA. The new addition to the family is the iPad 2,4. The 2,4 replaces the original iPad 2,1. It's also only available in a single capacity.


There's no known way to tell whether you're getting an iPad 2,4 vs. the older iPad 2,1 without opening the box. The 2,4 unit I ended up with was made in China, ruling out manufacturing region as a way of telling. The external box looks identical, as does the device itself.

The newer iPad 2,4 units should come with iOS 5.1 preloaded, while any older iPad 2,1 stock may have 5.0.1 or older. But the most accurate way to tell is by looking at what a utility like Geekbench will tell you about the hardware:

This particular iPad 2,4 sample came from Best Buy, and several attempts to find one elsewhere came up short. All indications seem to point to the iPad 2,4 being relatively rare, which makes sense considering what's inside it.
Although the iPad 2,1 and its 3G brethren all used a 45nm Apple A5 SoC, the iPad 2,4 uses a die-shrunk 32nm version. The performance remains the same, but the die is much smaller. This isn't however just a normal die shrink, as Apple is using Samsung's 32nm high-k + metal gate LP transistors for this new A5 die. Intel was first to make the HK+MG transition back at 45nm in 2007 and correctly predicted that no one else would make the move until 32nm at the earliest.

Transistors are amazingly complex to fully understand, but at a high level they're quite simple. Imagine a transistor as a silicon based switch. When on, current flows, and when off, current stops flowing. The smaller you make a transistor, the more likely it is to misbehave. If current flows while the transistor is off, you waste power. This is known as leakage current and can come from a number of sources.

One such source is the gate oxide/gate dielectric, a particularly thin part of modern day transistors - on the order of a handful of atoms thick. Thinning the gate dielectric is desirable up to a certain point, after which the dielectric simply leaks too much power. Switching to a different material here, specifically one with a higher dielectric constant (a higher k-value), can significantly reduce leakage current and mitigate this issue. This is exactly what the first part of Samsung's 32nm high-k + metal gate process does.

The second half of the new process is the introduction of a metal gate electrode. Switching from a polysilicon to a metal gate electrode results in higher drive current by elimination of a region of depleted conducting carriers between the gate electrode and gate dielectric.

The combination of these two innovations results in less wasted current and more efficient current delivery, which in turn can give us a more power efficient chip. It's a net win. It makes manufacturing more complex, and there's definitely a learning curve to implementing it, but after you get over that hurdle it becomes just another part of the process.

The More Cost Effective Die

Traditionally the move to a smaller process node brings about an increase in transistor density. As transistors get smaller, you can fit more of them into the same space (or the same number into a smaller space). It's this basic principle that makes Moore's Law work. If you can keep shrinking transistor size by about 50% every two years, you'll theoretically be able to double transistor count at the same cost every two years (or cut cost in half every two years). In practice it doesn't work this well. Newer processes are always more expensive than their predecessors initially and logic scaling is never perfect.

It's rare these days that we actually see a pure die shrink anymore. With Intel's tick-tock model we almost always see increases in functionality to accompany each process node shift. In the case of Ivy Bridge, we actually saw a significant increase in transistor count thanks to an improved GPU. With Apple's 32nm A5 however, we truly end up with a die shrunk version of the 45nm A5 SoC. About the only part of the computing world where we see these pure shrinks is in the console space where performance doesn't have to go up within a generation, but cost must go down.





45nm A5 (left) vs. 32nm A5 (right) - Source: Chipworks

 The original 45nm A5's die measured approximately 122mm^2. The new 32nm A5 has a surface area of only 69mm^2. That's actually amazingly good scaling at 57% of the old die size, as perfect scaling from 45nm to 32nm would be around 50.5%.

Die size comparison

Assuming Apple could make full use of a 300mm wafer (which it can't, wafers are round, chips are rectangular at best so there are some unusable chips), Samsung could deliver 579 45nm A5 die to Apple. The move to 32nm would give Apple 75% more die per wafer at 1015 chips. Again both of these numbers are over estimates as they assume full usage of the surface area of a wafer as well as 100% yields, but you can see the benefit of a smaller die. As long as wafer costs increase by a factor less than the 75% increase in number of die per wafer, Apple can effectively reduce SoC cost by going this route.

These ARM based SoCs are already fairly cheap - all selling well below $30 (many around $15) - so there's not a whole lot of cost savings here. On a product like the $399 iPad 2, where Apple needs to do its best to maintain margins while holding onto (and growing) market share, every last dollar matters.

Gate density vs. process node at Samsung

There's another motivation for Apple however. Just as with any good microprocessor company, its best to introduce a new process technology on a known architecture. It's also a good idea to introduce a new process technology on lower volume products. The combination of both of these minimize risk. Should there be something wrong with the new process, introducing a new architecture on it just means you now have two very complex things to debug - the process technology and the chip's architecture. Should the new process not yield very well initially, you'd be similarly screwed if you were depending on it for your highest volume parts.

32nm A5 in iPad 2,4 (Source: Chipworks)

Apple decided to try out Samsung's 32nm HK+MG process on the A5 used in the 3rd generation Apple TV and some of the new iPad 2s. The former is a relatively low volume product for Apple, while the latter still moves in significant quantities. To deal with that fact, Apple is continuing to ship the original 45nm iPad 2,1 alongside the new 32nm iPad 2,4. Any hiccups in Samsung's production of the A5 and there are still more than enough iPad 2,1s to go around. The risk of moving to 32nm is effectively mitigated, while the learnings Apple gains from building the 32nm A5 will pay off later this year as Apple ramps up production of a 32nm SoC for use in the next iPhone. It's a very smart strategy, one you would expect from an experienced chip company - not a device vendor. When you consider that Apple employs chip architects who have worked on everything from the Athlon 64 to the Cortex A15, Apple's behavior is no longer that surprising.



Apple gets two benefits from the iPad 2,4: lower manufacturing costs, and experience with Samsung's 32nm HK+MG process which it will later use in much greater volumes. What about customers who end up with an iPad 2,4? Better battery life and cooler operation, of course.

Impact of HK+MG at Samsung

Remember the basics of Samsung's 32nm HK+MG process: a 40% performance improvement at the same leakage, or a 10x reduction in leakage at the same switching speed. As the iPad 2,4 retains the same clocks as the initial iPad 2, the benefit realized is a significant reduction in leakage current. This translates to tangibly better battery life.


Significant Battery Life Improvements details at http://www.anandtech.com/show/5789/the-ipad-24-review-32nm-a5-tested/2
.....

Final Words

If Apple's A5 is any indication, Samsung's 32nm HK+MG process is extremely capable. Assuming Apple didn't change any fundamentals of its microarchitecture, the iPad 2,4's gains in battery life can be attributed directly to the process. The gains themselves are significant. We measured a 15% increase in our web browsing battery life, a nearly 30% increase in gaming battery life and an 18% increase in video playback battery life. Although Apple hasn't revised its battery life specs, the iPad 2,4 definitely lasts longer on a single charge than the original iPad 2.



If you're in the market for an iPad 2, the 2,4 is clearly the one to get - if you can find one that is. Unfortunately there's no sure fire way to tell that you're getting a 2,4 without opening the box and turning on the tablet, and I suspect most stores will get a bit irate if you're constantly buying and returning iPad 2s in search for a 32nm model. Presumably over time more of the available inventory will shift to 2,4 models, but based on our experiences in trying to find a 2,4 it's still pretty tough.







I would like to applaud Apple's 32nm migration plan. By starting with lower volume products and even then, only on a portion of the iPad 2s available on the market, Apple maintains a low profile and gets great experience with Samsung's 32nm HK+MG process. It's very clear that this is all in preparation for the next iPhone, which will almost certainly use Samsung's 32nm process and require it in significant volumes. It's obvious that Apple employs some very smart chip heads in Cupertino.



What I'd really like to see is a 32nm version of the A5X used in the new iPad. I don't know that there's much reason for that this year, especially when the 4th generation iPad will likely ship in the first half of 2013 with yet another new SoC (dual-core A15 + Rogue anyone?), but it'd still be nice to have. The power efficiency improvements are substantial and the 3rd gen iPad could definitely use them. Those of you who are waiting for the next iPhone should also be pretty happy about these results. Apple could easily deliver a higher clocked version of the A5 for the next iPhone while keeping power consumption equal to if not lower than where it's at today. The move to 32nm is going to be good all around it seems, and Samsung appears to be a very capable foundry partner for Apple. Despite all of the rumors of a rift in the relationship, the foundry side of things is working out well.