Create a set of PCB design flow processes that you can use as a guide to step you through the development of a PCB layout. An efficient design flow helps you avoid duplicating steps. Once you have completed a step, you should never need to repeat it.
A comprehensive design review should take place between all applicable disciplines: i.e. Hardware Engineer, Project Management, Layout, Mechanical, and Manufacturing.
For the PCB designer the following information needs to be determined: Layer stack-up and plane layers, PCB thickness and board material, default trace width, component complexity and quantity of new components, proto board or production/auto route or manual route, high speed rules, impedance control, testability and Schedule.
2. COMPONENT DATA SHEETS
Engineering Department will submit all component data sheets, (web link), prior to the start date of a PCB layout, of all of the components that cannot be located in your Library Handbook.
3. MECHANICAL DATA SHEET
Engineering Department will also provide a Board Outline constraint drawing if one is available, or as soon as possible. The mechanical constraint drawing should be drawn from the top side, include all mounting holes, fixed connector locations, indicate the Layer Stack-up and board thickness of the PCB. The origin for the constraint drawing should be the lower left mounting or tooling hole.
4. PART NUMBER & BOARD NAME ASSIGNMENT
After the Engineering Department submits the data sheets, a part number and a board name are assigned to the PC Board.
5. LIBRARY MANAGEMENT
As you create your library parts, using the naming convention that you developed, populate the applicable PCB Library with the new decals, representing the pin assignments and all applicable notes and documentation for each part. Keep the PLB file “Up to Date” every time new parts are built.
6. CUSTOM BOARD OUTLINE
Select the correct PADS “Start File” that matches the layering scheme that the Engineer has provided and copy the master “Start File” to a new name.
Fill out the Title Block.
Enter the Board Outline.
Add all Mounting/Tooling Holes and Fiducials that are necessary then glue them down.
Move the Targets to the outer extremities of the board outline.
Fully dimension the board edges and at least one mounting hole.
Create the “Auto router Keep-in/out” inside the Board Outline
7. STANDARD BOARD OUTLINE
If a Standard Board Outline is selected from the Library, the PCB Designer will fill out the Title Block and edit the text on Layer 26 that will eventually go on the Silkscreen.
Setup the correct Layer and Color Scheme.
At the start of the PCB design, the Engineering Department will provide a net list, from the schematic capture tool, in PADS format starting with the PADS-PowerPCB header:
The net list will contain all of the correct PADS Decal Shape Names.
The net list will not contain Pin Names over four characters long.
The following is a list of acceptable pin names: Collector = C, Emitter = E, Base = B,
Anode = A, Cathode = C, Source = S, Drain = D, Gate = G, Positive = 1, Negative = 2.
Import the netlist into PowerPCB. If errors are found, in the netlist, the Designer will report them to the Project Engineer. The Project Engineer will fix the problems and provide the PCB Designer with an updated netlist.
After the net list is successfully imported into PADS, the PCB Designer will Tools/Disperse the parts.
Create and e-mail to Project Engineer Unused Pins, Part List 2 & Statistic Reports.
PCB Designer must review Unused Pins list for 2 pin components.
Project Engineer must review Unused Pins list for possible schematic errors.
10. PART PLACEMENT
The Designer and Engineer will perform the part placement, or Engineers suggested layout.
The placement must meet the Engineers guidelines and design rules. Engineer will provide the design rules.
The placement must meet all manufacturing requirements.
The placement must meet all routability requirements.
Tools/Verify Design - check clearance to ensure no over lapping parts.
Use CAM Plane option and use a 2D-Line to separate the different Plane Nets, or use the Split/Mixed Plane option.
Use the View/Nets feature to discriminate different nets by color.
12. First (1ST) SET OF QUALITY CONTROL PRINTS (PDF Format)
1:1 scale Drill and Assembly drawing laser print or bond paper.
All new Library Decals must be checked for Solder Pattern accuracy.
Print Split Planes if applicable for Project Engineer to check.
13. FINAL PART PLACEMENT
After Split Planes and New library Decals are checked, PCB Designer will make final part placement adjustments.
PCB Designer will make final silkscreen adjustments.
14. GENERATE OUTPUT FOR MECHANICAL PART PLACEMENT 3D MODEL CHECKS USING SolidWorks or PRO‑E TRANSLATORS
Now that you have completed half of the job to complete a project, a more challenging task awaits you on Part 2 of this tutorial...