How Do I Submit A PCB Design That Doesn't Have A Schematic? - Page 1
Forum section: electronics / projects

author: German_EE
author_rank: Super Contributor
timestamp: August 30, 2018, 06:38:42 pm
content: Here's a strange one. I want some PCB's made but the design doesn't have a schematic, so how do I submit it to the PCB factories in China?PCB size 30mm x 100mm 1.6mm FR4Side 1 Groundplane with 1mm wide 25mm long slots in copper at 33mm and 66mmSide 2 5mm wide strip along one long edge with multiple vias through to groundplane sideThat's it, so how do I create the PCB design files if there is no circuit?

author: Aztlanpz
author_rank: Regular Contributor
timestamp: August 30, 2018, 06:42:38 pm
content: Submit the Garber files.

author: Benta
author_rank: Super Contributor
timestamp: August 30, 2018, 06:51:43 pm
content: A PCB manufacturer doesn't need the schematics, he couldn't care less. If you have the PCB layout, you submit:Bottom copperTop copperBottom solder maskTop solder maskTop silk screen (component placement, if relevant)Bottom silk screen (if relevant)Drill file (also includes outline milling)All as Gerber files with the extension .grb and .drl

author: Bud
author_rank: Super Contributor
timestamp: August 30, 2018, 06:55:55 pm
content: i guess he asked how to make a pcb design with no schematic present. Can't your PCB program just create PCB files alone? Just create a pcb file and place your tracks and vias the export to gerbers. If the package does not allow that you can always create a schematic with a single resistor.

author: Benta
author_rank: Super Contributor
timestamp: August 30, 2018, 07:03:15 pm
content: German_EE, on rereading your question, I think I understand what you mean.Your PCB layout program probably expects a netlist, which is generated from the schematic editor.My favourite PCB editor is FreePCB, which is very lightweight and easy to work with. In this (and probably all the other PCB layout editors) you can add a net manually.In your case, just add the net "GND" and route it freehand in the editor, meaning drawing outlines and using fills.

author: Dubbie
author_rank: Unknown
timestamp: August 30, 2018, 07:25:27 pm
content: Just be aware that if you don’t already have the pcb layout, it may be worth the effort to draw a schematic as it is a really good way of checking that everything is hooked up the way you’d expect. It’s often not visually obvious that a circuit has a wiring error on the pcb layout. If you have a correct schematic, you don’t even have to think about it. Your layout tool won’t let you create wiring errors.

author: DaJMasta
author_rank: Super Contributor
timestamp: August 30, 2018, 07:45:56 pm
content: Have you tried doing this in a CAD package? They may throw some errors, but I'd imagine you can just get it done and export the gerbers as normal. I haven't specifically tried, but I'm sure I could do this in CircuitMaker (free derivative of Altium Designer).You should be able to just define geometry for planes or traces with no nets. You could even add port indicators to define nets in the schematic but leave them unconnected, so you have separate nets for each of your PCB elements and you can still use all the normal design rules for clearance and such.

author: Benta
author_rank: Super Contributor
timestamp: August 30, 2018, 08:41:09 pm
content: Quote from: Dubbie on August 30, 2018, 07:25:27 pmThis is the schematic:

author: dmg
author_rank: Regular Contributor
timestamp: August 30, 2018, 09:23:31 pm
content: Not that rare, in my previous job we had some RF/microwave guys that did all sorts of crazy things with PCB's for microwave voodoo. They used microwave design software and export the geometries to standard formats such as gerber or DXF and off it goes to the fabs, normally without issue. Also there are people who design PCB's with autocad or inkscape or just about any CAD software. As long as you export things to formats that PCB manufacturers can understand you're good to go. Just try to use gerber and be sure that layer polarity and geometry definitions agree with what PCB manufacturers expect. Try to make all layers with positive polarity (i.e. painted areas in layer drawing = copper) and don't forget to define the board outline.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: August 31, 2018, 03:57:27 pm
content: Quote from: Benta on August 30, 2018, 08:41:09 pm^You'll probably need one pin, a test point or something (it can be a tented SMT pad so it doesn't even affect the board fab) to connect to the copper. That's about it.If you can place copper arbitrarily without assigning nets -- using fills or whatever, just go and do it, no nets needed even.Tim