PCB-NOWAY

I would not expect anything high quality with defined impedance from a sub 2 USD PCB

You run a professional joint, order from a professional supplier accordingly

Cheers

Klaus

If you insist on $2 boards, learn their standard stack-up, and design to that. It's probably the same as what other PCB houses would like to use. Let us know the values.

Any reasonable stackup would have worked. This isn't reasonable.

Have you contacted them and ask if they can do what you wanted at the price quoted. Could have just been a new guy made a mistake. They still have your order, they should send it free if they want your business. Mikek

It's not worth getting and stuffing another board from them. It has around $400 of parts on it, and a lot of assembly and engineering time.

We're cutting the trace widths down, to get closer to 50 ohms, but losses will go up.

I think we learned enough from the proto board to go for the real product, which would be fabbed by Cirexx or Gorilla.

The Chinese houses are cheap and fast, but quality is bad. I wouldn't mind finding a quick-turn proto house that charges more but actually reads fab drawings.

We had two other problems on this proto. The Coilcraft conical inductor, and the Hittite distributed amplifier, both have their lids attached with low-temp adhesive, maybe not washable with water or solvent. Both lost their lids but still work.

I can only find 3 copper layers there? I have had good luck with E- Teknet, but they sure don't do $2 boards, unless you order hundreds. I do 2, 4 and 6-layer boards with them, and have had great results on several hundred orders over more than 10 years.

Jon

You get what you pay for. The Chinese make most of the electronics we all use. Clearly they are capable of making quality electronic goods. You just need to select a quality vendor rather than the cheapest you can find.

tirsdag den 3. december 2019 kl. 21.04.46 UTC+1 skrev John Larkin:

hmm.. googling it seems like it is default stackup for a whole lot of manufacturers, one 0.11mm layer of prepeg between 1-2 and 3-4

That section didn't show all 4 layers, but 1-2 and 3-4 are similarly paper-thin.

I was looking for a maybe cheapish but especially quick proto shop to fab engineering test boards. I guess I'm still looking. I'll try e-teknet.

That's amazing. Every trace becomes a big capacitor. Expect weird behavior. We're talking over 200 pF per square inch from L1 to a L2 ground plane.

I talked to a nice guy from E-Teknet. He says they actually read fab drawings.

Yikes. We've never had a problem like that with PCBWay, in probably 20 orders. Maybe Pentalogix?

Cheers

Phil Hobbs

did you order from the standard menu or like John, ask cook to make something special?

Oh, was that Sam ? It's his company or used to be at least.

They were very good for us many years ago. He got a bit more expensive than others but his companies do good work.

My purchasing lady ordered it. But PCBWAY has annoyed us before.

No, it was Ronaldo. I filled out the contact form, and he called me and we talked for a while. He actually knew where Potrero Avenue and Pot Hill are.

onsdag den 4. december 2019 kl. 01.13.48 UTC+1 skrev John Larkin:

I think there are banned from the EEVblog forum because they were constantly spamming

Am 04.12.19 um 01:13 schrieb John Larkin:

I have done a lot of jobs by PCBway, and not the slightest complaint. They even spotted that I had solder mask on part of the pads for these ultra-tiny nekkid GaN transistors with solder balls on the silicon carrier, and when I OKed it, they processed it flawlessly on the same day.

The purchasing lady is not qualified for ordering pcbs with nonstandard layer structure. If she was, she could do GHz layout. What layer stack would you choose for a FPGA with 1000 Balls that has lots of JESD-204B 100 Ohm differential inputs? Probably not one where a 50 Ohm line is 120 mils wide.

cheers, Gerhard.

PCBWAY did this for me:

They really expanded, and offset, the solder mask.