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Smaller A5 Chip From Tweaked Apple TV Contains Only One CPU Core, Revamped Analog Circuitry

For the past few days, we've been following the story of the smaller A5 chip found inside of the recently tweaked Apple TV, seeking to understand what changes Apple has made in order to shrink the chip to roughly half the size of the previous A5 chip.

Yesterday, experts at Chipworks determined that the new A5 was still being manufactured by Samsung using the same 32-nanometer process used for the previous version, indicating that Apple had undertaken significant design changes for the chip.

Chipworks now has a full image of the A5 die, revealing that this smaller A5 chip contains only a single-core ARM CPU. Apple has listed the Apple TV as having a single-core A5 since the third-generation model launched last year, but the previous design involved a dual-core chip with one core disabled, while the new design contains just the one active core. The new A5 does still contain the same dual-core GPU found in the previous version of the chip.

a5_7498_die
Chipworks' Dick James tells us, however, that there must be more to the story in order to achieve a nearly 50% size reduction, but the firm has yet to determine exactly what other changes are contributing to the smaller die size.

A separate observation of interest involves the analog circuitry included on the chip. This new A5 chip appears to take advantage of optimized analog components such as resistors, capacitors, and inductors, yielding a mixed signal chip that seems to be a rather significant technical achievement at the 32-nanometer process node.
My guess is that the analog sections have been re-designed, always a work in progress when we get this small, since analog circuitry does not shrink anywhere near as predictably as digital. And as Jim said earlier, we think this is now in a mixed-signal version of the 32-nm process that allows extra passive components such as resistors, capacitors, and inductors, that is much more suited to analog stuff.
It is still unclear exactly why Apple has elected to redesign the A5 for the Apple TV, as it has been assumed that the company's "hobby" does not generate enough shipment volume to warrant such an investment in and of itself. As a result, it is possible that Apple has plans to use this chip in other products, although the single-core nature of the CPU design will likely limit the range of devices for which it would be suitable.

Related roundup: Apple TV

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21 months ago

It is still unclear exactly why Apple has elected to redesign the A5 for the Apple TV, as it has been assumed that the company's "hobby" does not generate enough shipment volume to warrant such an investment in and of itself. As a result, it is possible that Apple has plans to use this chip in other products, although the single-core nature of the CPU design will likely limit the range of devices for which it would be suitable.


iWatch, obviously. :rolleyes:
Rating: 16 Votes
21 months ago
A5 powered iWatch here we go
Rating: 9 Votes
21 months ago
You guys are reading too much into the word "Analog".

All electronics circuits are analog. There is no such thing as a pure digital signal, it is just how its interpreted. All power and ground supplies are analog, all high-speed gigabit transmission paths are in +/- pairs and are much more analog than digital in how they are handled in board routing, impedance matching, etc.

Every circuit trace has capacitance and impedance, no voltage is stable enough to be 100% to an exact level at all times.

Hence, chips have analog function hardware... most often in the I/O drivers for transmit and receive logic on each pin, as well as for filtering power, powering on / off sections of the chip, and for Phased Lock Loops which are heavily used in microprocessors / SOCs.

Analog does not mean they are hooking up speakers or ancient technology directly to the chip. In-fact that would be a bad idea.

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As opposed to chips they already have in production? Why would they spend the "R&D" money to figure out how to make it smaller when they are already cranking out a ton of these puppies for a variety of different devices....


Actually, while you just stated it indirectly, that is a good point... there are multiple devices using the chip... what happens when there aren't? A5 is used on older designs. Maybe the single-core A5 Apple-TV is about to be the only thing left using the A5 processor in a few months. Why keep building a larger CPU than needed?
Rating: 8 Votes
21 months ago

Any chance this will be used in the iPhone 5S? It may be a slight reduction in performance, but the increase in battery life and the ability to shrink the device pretty significantly might be worth it.


Well, a snowball's chance in hell is still a chance, I guess, so the answer is yes. :)
Rating: 7 Votes
21 months ago

Any chance this will be used in the iPhone 5S? It may be a slight reduction in performance, but the increase in battery life and the ability to shrink the device pretty significantly might be worth it.


No.

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iTV

TV speakers are analog
maybe lots of other parts in a TV as well


Why on earth would they worry about "shrinking" the size of the chip if they're simply going to put it in a TV.....
Rating: 7 Votes
21 months ago

Well, a snowball's chance in hell is still a chance, I guess, so the answer is yes. :)


Rating: 7 Votes
21 months ago

Shouldn't even need as much horsepower as a single core A5.


But a low power, low clocked A5 would be a nice, cheap chip to maximise battery life, no?
Rating: 5 Votes
21 months ago
Yay!

**** you first revision third gen Apple TV!

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Any chance this will be used in the iPhone 5S? It may be a slight reduction in performance, but the increase in battery life and the ability to shrink the device pretty significantly might be worth it.


Um... I too enjoy smoking weed sir.

The iPhone 5 utilizes the A6 chip, the 5S is expected to come with the A7.
Rating: 5 Votes
21 months ago

... but the previous design involved a dual-core chip with one core disabled, while the new design contains just the one active core.

... It is still unclear exactly why Apple has elected to redesign the A5 for the Apple TV, as it has been assumed that the company's "hobby" does not generate enough shipment volume to warrant such an investment in and of itself. As a result, it is possible that Apple has plans to use this chip in other products, although the single-core nature of the CPU design will likely limit the range of devices for which it would be suitable.


I'd guess that shipping two cores and only using one was a way of increasing yields (aka minimizing cost.)
Pushing the envelope with a new process will result in unusable cores.
Using the better of the two cores (or whichever one actually worked) "saved" some chips.
Maybe by now the process has been perfected so a single core can be reliably manufactured.

And, because Apple TV is a relatively low-volume product, there's less pressure. Big deal. Its only Apple TV.
Shrinking die size could cause delays, which would be costly with high-volume products.
If Apple TV A5 yields are below expectations, then slip the estimated ship dates. So what?
If yields are OK, then run off a batch of chips and you're good for months. Yay.

Of course, if you were paranoid, you might think that Apple is doing two things with the Apple TV A5.
1. Limit the amount of advanced chip design that Samsung sees. For obvious reasons.
2. Give TSMC a low-risk chip to make, to improve their process and to test their quality.
Rating: 5 Votes
21 months ago

I was thinking set top box too.

Is anything still broadcast w an analogue signal? If so, this might explain the mods.


Or what about a low cost iPhone?
Rating: 4 Votes

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