Art or Engineering?

[nukie]

The people who are responsible for this must have a very tiny desk space to work with.

[marshallh]

Wonder how many layers

[JDubU]

Microvias in pads?

[DanielS]

Wonder how many layers

With IC manufacturers often optimizing their ball-outs around their reference design's companion ICs' ball-outs, I would not be surprised if the board only required four layers.

[miguelvp]

The people who are responsible for this must have a very tiny desk space to work with.

Nobody has round desks

btw, link to the ifixit site or similar teardown site where this came from?

[ConKbot]

Wonder how many layers

With IC manufacturers often optimizing their ball-outs around their reference design's companion ICs' ball-outs, I would not be surprised if the board only required four layers.

with that load density, and only 4 layers, that means the entire BGA would be broken out on the bottom layer, or be naughty and do routing on the power/ground planes.  I'd believe 6 layer, not 4 though.

[aargee]

Maybe it is art and not routed at all.

[miguelvp]

Motorola smartwatch?

Yup looks like it:
http://9to5google.com/2014/09/09/motorola-moto-360-smartwatch-teardown-finds-less-than-advertised-battery-life/


https://www.ifixit.com/Teardown/Motorola+Moto+360+Teardown/28891

[miguelvp]

But wait, under that big chip there is...



Another one

I wonder why they even looked, someone must have hint them.
Edit: oh wait yeah, I guess they couldn't find a micro anywhere.

[DanielS]

I wonder why they even looked, someone must have hint them.
Edit: oh wait yeah, I guess they couldn't find a micro anywhere.

And stacking CPU/SoC with the DRAM is becoming increasingly common - gets rid of half the board-level routing complexity around the SoC area. It also makes the CPU-DRAM traces short enough that you can disable termination - a pretty big energy-efficiency boost when you only have a 300mAh battery.

[Zad]

Lets face it, the Raspberry Pi uses a stacked CPU+memory chip which was already "mature" (i.e. old) when the Pi came out, as it had been used in phones for some time before.

It does strike me that there is a lot of passives on that watch board. You would think that at least some of them could themselves be baked into the chips themselves. You are never going to totally get around that of course, but it could have made that particular designer's job a lot easier.

[Smokey]

The thing that gets me is the absolutely huge volume they must be buying the bare boards at in order to have a reasonable final product sale price.  All that ultra miniature PCB technology is expensive to make.  Even if you got the size down you can't end up with a PCB that costs $200USD apiece and sell the watch for $250

[calexanian]

Motorola smartwatch?

Yup looks like it:
http://9to5google.com/2014/09/09/motorola-moto-360-smartwatch-teardown-finds-less-than-advertised-battery-life/


https://www.ifixit.com/Teardown/Motorola+Moto+360+Teardown/28891

That would be my guess. Those connectors are right out of a smart phone.

[miguelvp]

That would be my guess. Those connectors are right out of a smart phone.

Only reason I guessed was because it get emails from techrepublic and I recalled seeing a watch, I usually don't follow the links just skim over the email. But when Apple introduced their apple watch it kind of trigger thinking that it couldn't be a coincidence Motorola announced theirs just a bit earlier, the round shape made me look for a teardown of the moto 360 (not to be confused with the game console).

The apple watch at least it has IR LEDs and sensors to monitor your blood pressure and heart beat so I've heard. Also recently I did stumble on a paper of using just that same technique and the reason was Dave's video about the heart monitor.

So I guess watches are making a comeback even if as a fad. It might help the real watches that people wear for real prestige not these so called practical things

[EEVblog]

Wonder how many layers

On a board like that with no room for traces on the top, you'd be looking at 6 layers.
2 layers for ground and power (extra PITA if you have multiple rails) and 3 for routing.
A 4 layer board would be a Murphy free miracle.

[EEVblog]

Maybe it is art and not routed at all.

That technique is called Homeopathic Routing 

[free_electron]

you shoud take a look at the logic board of the latest ipad.
that thing uses 01005 caps and an embedded resistive layer. they etch the resistors ...
the 01005 are lost in the underfill material used to keep the flip chips on the board.

apple has posted an x-ray picture of the PCB in the new iWatch... droooolll me wanna do layouts like that !

[EEVblog]

apple has posted an x-ray picture of the PCB in the new iWatch... droooolll me wanna do layouts like that !

Get in line!
That sort of stuff isn't exactly generate gerbers and then wait for your board to come back. You'd spend months at the specialist PCB manufacturer and assembler, and any place required researching the exotic techniques and materials and trialing them out and negotiating custom process improvements etc.
Wouldn't surprise me if the Apple PCB designers and production people were working on that board for the last year.

[ConKbot]

Lets face it, the Raspberry Pi uses a stacked CPU+memory chip which was already "mature" (i.e. old) when the Pi came out, as it had been used in phones for some time before.

It does strike me that there is a lot of passives on that watch board. You would think that at least some of them could themselves be baked into the chips themselves. You are never going to totally get around that of course, but it could have made that particular designer's job a lot easier.

The back side of the board is nearly empty so it can fit a battery flat against it, so it looks like all the decoupling caps made their way upto the front side.

Hence the marching line of ants around the cpu/ram 

[tszaboo]

you shoud take a look at the logic board of the latest ipad.
that thing uses 01005 caps and an embedded resistive layer. they etch the resistors ...
the 01005 are lost in the underfill material used to keep the flip chips on the board.

apple has posted an x-ray picture of the PCB in the new iWatch... droooolll me wanna do layouts like that !

And when I say things like Rigid-flex PCB or IMS, my bosses look at me like I want to rip them off with some space technology.

[lapm]

Save that bcp, it must be unobtainium to be cramped that tight... 

[DutchGert]

you shoud take a look at the logic board of the latest ipad.
that thing uses 01005 caps and an embedded resistive layer. they etch the resistors ...
the 01005 are lost in the underfill material used to keep the flip chips on the board.

apple has posted an x-ray picture of the PCB in the new iWatch... droooolll me wanna do layouts like that !

Where can we find those ?

[DanielS]

Where can we find those ?

01005s? Under the carpets of most parts distributors.

I imagine those things are nearly impossible to find if you accidentally drop them from their reel.

Hand-soldering components that are almost too small to see with the naked eye sounds like an interesting hardcore challenge.

[DutchGert]

Where can we find those ?

01005s? Under the carpets of most parts distributors.

I imagine those things are nearly impossible to find if you accidentally drop them from their reel.

Hand-soldering components that are almost too small to see with the naked eye sounds like an interesting hardcore challenge.

I mean the x-rays

[Alex Eisenhut]

Very nice. I've worked on several HDI designs and it's fun. The challenge is to get rid of all your old habits but that goes quickly. Visualizing the vias in the stackup can be confusing at first.

Something I do a lot these days with non-HDI through-hole SMT designs is pouring isolated power planes on outer layers, this gets rid of a lot of vias and frees up layers.