Art or Engineering? - Page 1
Forum section: electronics / projects

author: nukie
author_rank: Frequent Contributor
timestamp: September 12, 2014, 12:52:06 am
content: The people who are responsible for this must have a very tiny desk space to work with.

author: marshallh
author_rank: Unknown
timestamp: September 12, 2014, 01:03:51 am
content: Wonder how many layers

author: JDubU
author_rank: Frequent Contributor
timestamp: September 12, 2014, 01:30:26 am
content: Microvias in pads?

author: DanielS
author_rank: Frequent Contributor
timestamp: September 12, 2014, 01:31:41 am
content: Quote from: marshallh on September 12, 2014, 01:03:51 amWith 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.

author: miguelvp
author_rank: Super Contributor
timestamp: September 12, 2014, 01:35:16 am
content: Quote from: nukie on September 12, 2014, 12:52:06 amNobody has round desksbtw, link to the ifixit site or similar teardown site where this came from?

author: ConKbot
author_rank: Super Contributor
timestamp: September 12, 2014, 01:36:44 am
content: Quote from: DanielS on September 12, 2014, 01:31:41 amwith 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.

author: aargee
author_rank: Frequent Contributor
timestamp: September 12, 2014, 01:42:17 am
content: Maybe it is art and not routed at all.

author: miguelvp
author_rank: Super Contributor
timestamp: September 12, 2014, 01:43:58 am
content: 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

author: miguelvp
author_rank: Super Contributor
timestamp: September 12, 2014, 01:50:49 am
content: But wait, under that big chip there is...Another oneI wonder why they even looked, someone must have hint them.Edit: oh wait yeah, I guess they couldn't find a micro anywhere.

author: DanielS
author_rank: Frequent Contributor
timestamp: September 12, 2014, 02:13:57 am
content: Quote from: miguelvp on September 12, 2014, 01:50:49 amAnd 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.

author: Zad
author_rank: Super Contributor
timestamp: September 12, 2014, 03:15:54 am
content: 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.

author: Smokey
author_rank: Super Contributor
timestamp: September 12, 2014, 04:16:07 am
content: 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

author: calexanian
author_rank: Super Contributor
timestamp: September 12, 2014, 04:30:12 am
content: Quote from: miguelvp on September 12, 2014, 01:43:58 amThat would be my guess. Those connectors are right out of a smart phone.

author: miguelvp
author_rank: Super Contributor
timestamp: September 12, 2014, 04:44:48 am
content: Quote from: calexanian on September 12, 2014, 04:30:12 amOnly 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

author: EEVblog
author_rank: Unknown
timestamp: September 12, 2014, 04:59:13 am
content: Quote from: marshallh on September 12, 2014, 01:03:51 amOn 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.

author: EEVblog
author_rank: Unknown
timestamp: September 12, 2014, 05:02:06 am
content: Quote from: aargee on September 12, 2014, 01:42:17 amThat technique is called Homeopathic Routing

author: free_electron
author_rank: Super Contributor
timestamp: September 12, 2014, 05:15:45 am
content: 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 !

author: EEVblog
author_rank: Unknown
timestamp: September 12, 2014, 05:40:46 am
content: Quote from: free_electron on September 12, 2014, 05:15:45 amGet 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.

author: ConKbot
author_rank: Super Contributor
timestamp: September 12, 2014, 05:46:00 am
content: Quote from: Zad on September 12, 2014, 03:15:54 amThe 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

author: tszaboo
author_rank: Super Contributor
timestamp: September 12, 2014, 06:51:16 am
content: Quote from: free_electron on September 12, 2014, 05:15:45 amAnd 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.

author: lapm
author_rank: Frequent Contributor
timestamp: September 12, 2014, 08:08:44 am
content: Save that bcp, it must be unobtainium to be cramped that tight...

author: DutchGert
author_rank: Frequent Contributor
timestamp: September 12, 2014, 11:46:46 am
content: Quote from: free_electron on September 12, 2014, 05:15:45 amWhere can we find those?

author: DanielS
author_rank: Frequent Contributor
timestamp: September 12, 2014, 12:32:52 pm
content: Quote from: DutchGert on September 12, 2014, 11:46:46 am01005s? 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.

author: DutchGert
author_rank: Frequent Contributor
timestamp: September 12, 2014, 01:08:07 pm
content: Quote from: DanielS on September 12, 2014, 12:32:52 pmI mean the x-rays

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: September 12, 2014, 03:28:42 pm
content: 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.