<azonenberg>
They've got much lower prices than an EU/US fab, but are very much a high end shop
<azonenberg>
they can do moderate volume but it seems like prototyping is one of their specialties
<azonenberg>
I've used a fair number of fabs over the years and i keep coming back to them
<azonenberg>
great customer service, the salespeople speak decently good english
<azonenberg>
they don't make changes to your boards silently, they always message you back with questions if something seems off or is difficult/impossible to manufacture
<azonenberg>
one time they caught that my board wasn't quite square, one corner was like 100um to the right of the opposite one
<Degi>
lol
<azonenberg>
i caught their CAM engineering team in a mistake *once* in all the time i've been working with them, they missed that a trace had no soldermask and calculated impedance with mask
<azonenberg>
so the suggested changes to trace width were massive compared to what i had in my design
<azonenberg>
i re-ran the numbers in sonnet and asked them to double check
<azonenberg>
they apologized, said my numbers were correct, and proceeded with the order
<Degi>
Hmh they recalculate traces for you?
<azonenberg>
if you say controlled impedance, they'll double check your parameters are sane
<azonenberg>
then they TDR a sample trace on each panel and verify it's within tolerance
<azonenberg>
they also cross section a board or two on each order and take measurements of copper, soldermask, and dielectric thicknesses, via sidewall plating thickness, etc
<azonenberg>
and do a solderability test where they dip a board into a solder pot and make sure all of the pads take the solder properly
<azonenberg>
This is what happens when you work with a high end fab instead of one like jlc :p
<Degi>
How did they get 52.22 max 46.56 min 53.62 average for impedance lol
<Degi>
whats float solder
<azonenberg>
I think the translation just has the wrong columns
<azonenberg>
min 46.56, max 53.62, average 52.22
<azonenberg>
i found one or two small typoes in the QA report but the data looked good
<azonenberg>
Float solder i think means they have a pot of molten solder and float the board on top of it
<Degi>
How big of a pot? They can make PCBs nearly a meter square
<azonenberg>
No idea. they may just cut a piece off for huge boards
<azonenberg>
generally the cross section comes from the board they do the solderability test on
<azonenberg>
so they are cutting it up anyway
<Degi>
Hm what do pcbs cost there like
<azonenberg>
The probe characterization board is 75 x 25 mm, 2 layer RO4350B, immersion silver, controlled impedance on one layer
<azonenberg>
10 board was $10/board, $220 setup fee, $45 shipping, $15 currency conversion fee, $380 for the order
<Degi>
huhh
<azonenberg>
So, not JLC pricing (they have i think a 200 USD minimum for all orders)
<azonenberg>
But for what you get, it's not bad at all
<azonenberg>
Like i said they're a high end shop
<Degi>
Cool jlc now has red, blue and black soldermask
<Degi>
available at no extra csot
<Degi>
Hmm I think I used Tg 130-140 °C instead of Tg 155 °C for my 4 layer board, hope its ok
<azonenberg>
Yeah i always spring extra for higher Tg to ensure good performance. Even 155 is a bit light IMO
<azonenberg>
My minimum material for new designs is Isola 370HR which is 180 Tg
<azonenberg>
That's as low end as i go
<Degi>
Hm the problem is that during reflow it may get damage?
<azonenberg>
Yes. Or flex
<Degi>
Hmm theres excess soldermask and a bit missing soldermask on one of the 200x boards
<Degi>
Yeah maybe I should do a dry run with the reflow device
<Degi>
And excess HASL solder on some palces
<azonenberg>
For higher speed stuff, i use Isola FR408HR (Tg 190, this is what OSHPark uses by default)
<azonenberg>
or Rogers RO4350B, which has a Tg of >280C
<azonenberg>
Which makes sense because 4350B is a hydrocarbon-ceramic material and not epoxy-glass based
<Degi>
4 layer pcb looks good on inspection
<Degi>
Soldermask pretty even
<Degi>
Hmm maybe next time 0201 for PCIe decoupling
<Degi>
Hm meh I couldve routed the RF traces differently, then they'd be a bit more length matched though arrive at different receivers. I think that shouldnt be a problem since pcie doesnt care about length matching
<Degi>
I wonder why smaller vias have soldermask but bigger vias dont
<Degi>
Hmm some traces are really close by, hope they dont get shorted in reflow lol
<Degi>
There is no ground plane on the backside of the PLL, only on one of the interior layers. Meh its not gonna make that much heat anyways
<Degi>
Maybe next time no soldermask above RF traces or at least calculate impedance with soldermask... Not sure if kicad pcbcalc can do that
<Degi>
Lol I should use BOMs, this PCB has many components which I didnt order (but it can work without them)
<azonenberg>
yeah as part of my layout review i verify all packages are right for the component
<azonenberg>
so as i do that i check that i either have them in inventory or add to my digikey cart
<Degi>
I mean the packages are right, I just forgot to order LEDs and a fuse
<Degi>
Hm oh, I need a 3.3 V ISP device too
<Degi>
How to align soldermask
<Degi>
The metal thingie
<Degi>
Meh i should watch a vid
<monochroma>
carefully :3
<Degi>
Like damn it needs to be less than like 0.2 mm it took a while, but how to keep aligned during paste application?
<Degi>
I guess just glue it down with tape
<Degi>
And then hope for the best and rework it
<monochroma>
that's the tricky part, you usually build a jig (commonly out of other PCBs) for your PCB, then spend forever aligning the mask and taping it down
<Degi>
I have 5 of this PCB
<Degi>
So yeah I could do that
<Degi>
Hm idk bga would probs be easier
<Degi>
Since that would at least have 0.8 mm instead of 0.5
<monochroma>
mask liftoff needs to be quick rather than slow (but yaknow.. not too fast...) to have a smol vacuum
<monochroma>
(also assuming this is a metal stencil)
<Degi>
Why a vacuum
<Degi>
Wont that make the paste flow aprt
<Degi>
Yeah metal stencil
<monochroma>
IPC guidelines say you want a good gasket to the board, so you get a slight vacuum during liftoff so the paste releases better from the stencil, and smears less
<azonenberg>
Degi: what i do is i tack the stencil down with a tiny piece of tape on one side so it's easy to move and align
<azonenberg>
get it lined up, tack the other side, then put a longer strip of tape along the first side to firmly secure it
<azonenberg>
then apply the paste, carefully lift under the tape on the far side with tweezers, and rotate it up using the long tape strip as a hinge
<lain>
TIL digikey has products NOT shipped by digikey o.o
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<bvernoux>
hi
<bvernoux>
I have finally found a spanner set ultra thin for SMA ;)
<bvernoux>
BGS 8646 | Combination Spanner Set | Stubby Type | 4 - 10 mm | 8 pcs
<bvernoux>
Advantage is there is 5.5mm and it is thin as 1.6mm
<bvernoux>
very nice for my VNA calibration kit Female-FEmale thru
<bvernoux>
as the ultra thin 5.5mm spanner is hard to find especially here it shall be less than 2.5mm
<electronic_eel>
bvernoux: BGS tools are usually not the best quality
<electronic_eel>
have a look at the Hazet 440 series instead, they are nice
<electronic_eel>
I have a full set of those for accessing tight spaces
<electronic_eel>
the 5.5mm one is exactly 2mm thick
<bvernoux>
ha interesting
<bvernoux>
hmm Hazet will take more than 30days ...
<bvernoux>
but interesting for next time I will buy spanner especially 8mm & 5.5mm mainly for my VNA Calibration Kit
<monochroma>
there were a bunch of digital camera projects back in the 80s that used decapped DRAMs as the sensor
<Degi>
I found an instruction somewhere to build a camera from a quartz topped EPROM and a lens xD and it makes shitty images but kinda nice demo. I guess back then CCD/CMOS was pricy
<Degi>
I even have two vidicon-like tubes
<Degi>
Hm why is the HMCAD so much cheaper than comparable ADCs and has so much more features
<Degi>
Like I guess nobody buys that stuff and thus companies dont care?
<monochroma>
it was cheap to begin with
<monochroma>
analog devices got the line when they gobbled up hittite microwave
<lain>
the hmcad1511 was crazy cheap, it was only $30 back in 2007 on mouser
<lain>
it was by arctic silicon devices, a fabless startup
<lain>
then hittite bought them and raised the price, and then analog bought them and raised the price again
<Degi>
Hm ugh yeah
<Degi>
Hmh why are ADCs so pricy anyways? Is it because of low volume?
<Degi>
For example modern CPUs with more silicon area and smaller features cost way less... (I mean in the 1 GS/s range ADCs are mostly silicon, rihgt?)
<azonenberg>
lower yield? more R&D effort amortized over less chips?
<azonenberg>
just guessing
<monochroma>
analog circuitry tends to be large due to the nature of the physics, so large and specialized process nodes are used, so you get less out of a wafer as well
<azonenberg>
that too, but doesnt explain how a hmcad1520 is $100+ and is a tiny qfn package while an xc7a100t is 28nm and has a die the size of the whole hmcad *package*, and around the same price
<azonenberg>
also btw, shipment from shapeways is coming tomorrow
<azonenberg>
it's either the samples i ordered of the old probe shell in a couple of materials, the new probe shells, or both
<sorear>
if you took apart the modem in a new high-end smartphone (let’s imagine a magic FIB here, don’t worry about what signals are exposed) how many ADCs would it have and what bandwidth and resolution?
<azonenberg>
i would imagine a fair number
<azonenberg>
even a modern ethernet PHY will have a fair few
<monochroma>
modern PHYs have entire DSPs :O
<lain>
I know the hmcad1511 was so cheap back in the day because they leveraged a very clever architecture with lots of DSP to reduce the size and required tolerances of the analog silicon
<lain>
most standalone ADCs, as I understand, are still heavily analog, so, lower yield and larger silicon area
<monochroma>
need some scope food
<lain>
:3
<Degi>
Hm yeah, yield...
<Degi>
HMC1061 / 661 seem interesting
<Degi>
That would be really nice for splitting a high frequency signal into multiple lower frequency signals but its priicy
<Degi>
azonenberg: With that IC you could do a 10 GHz sampling scope where it only needs to do a 1D scan (I think? Not sure how long its hold time is tbh)
<azonenberg>
Degi: i could do 18 GHz with that
<azonenberg>
more importantly, i could also use it for higher bandwidth interleaved oscilloscopes
<Degi>
Yes but the cheaper one is like 600 bukcs
<Degi>
I'm not sure what better things the fancier one can do? Like it has two SH in series but of what use is that?
<azonenberg>
I see it as potentially being useful for MURDOCK
<azonenberg>
Not for lower end stuff
<azonenberg>
We could push MURDOCK past 6 GHz if we did that
<Degi>
Hm yeah
<azonenberg>
since we no longer are limited by ADC front end bandwidth
<Degi>
Maybe 5 AD9213?
<azonenberg>
let's worry about that once i have $50K or more to spend on prototyping :p
<Degi>
rip
<azonenberg>
Which i currently do not. Lol
<Degi>
Also gotta use RF materials
<azonenberg>
well obviously
<azonenberg>
but a little bit of RO4350B is probably going to be the least expensive part of that scope
<azonenberg>
except maybe the screws that hold the board into the enclosure :p
<Degi>
Lol
<Degi>
Solid gold screws?
<Degi>
Tbh solid gold screws would be way cheaper than that SH lol
<Degi>
I think it should be possible to use a RF amplifier as a comparator too to get a comparator beyond 10 GHz (though at worse quality)
<Degi>
Read the datasheet tho, at higher amplitudes it seemingly has less tracking BW but the sampling BW remains at 18 GHz. not sure what that means
<Degi>
Ohh its a dual rank track and hold, that makes that the output is at a constant value (because for a single track and hold, the output would be varying for the track duration)
<azonenberg>
ah ok that makes sense
<Degi>
Though only 4 GS/s is kinda meh
<Degi>
Like the AFE is gonna be big monies if you wanna use the full BW
<azonenberg>
For sure
<Degi>
Maybe short of 20k
<Degi>
Or 30k
<Degi>
Much fun getting sufficiently good ESD diodes if at all
<azonenberg>
oh i'm going to assume something that wideband will have ~zero esd prot
<Degi>
Like it costs 30k and breaks when you touch it
<Degi>
Hm on my PCB the holes on the front layer are perfectly aligned but on the back layer theres some ~150 µm misalignment with some holes
<Degi>
And some weird stuff in the PCB, I guess prepreg marks (the red stuff on them)
<Degi>
I think the drill went sideways since the offset is different for different ohles