Choose Unified Symbols for Your PCB Prototype Design Documents
I love spending hours at the bench soldering parts together and looking at the resultant signals they produce. It is satisfying to see the signals take shape on the oscilloscope as I refine each block. I’m surrounded by tools and equipment, little bits of wire and solder strewed from the invention process. Joining the beautiful mess are scattered components pulled from sample parts binders stored in the lab.
Soon my prototype design will be ready for build and I’ll have to move back into my cube to draw the schematic. This is where I’ll organize my thoughts and begin preparation of the design documents. One of the design documents will include a set of instructions to build the prototype, including the list of parts.
If I’m transitioning from my circuit sketch to a schematic capture, I’m going to open libraries searching for the parts I’ve been thinking about. If I can find them, great. Searching for alternates require queries within the tool. These can be grueling, fruitless, and result in a new datasheet to the PCB librarian. At some point, I’m done searching and placing components onto the schematic, and I’m ready to run a Bill of Material.
Anticipating Your Prototype: Pre-Planning Your Design
Choosing symbols to represent discretes is straightforward in most schematic capture programs. Resistors, capacitors, and inductors share universal symbols and values. Many ICs are available in parts libraries of schematic capture programs that represent myriad choices for analog and logic parts.
But frequently, the information contained in the symbol stops with the graphic. It would be great to have more information contained in the symbol and have it propagate through to assist preparation of the production documents.
Access information in one place with
The PCB layout designers take specific details from datasheets on package types to plan respective footprints and give procurement partners vendor names and part numbers for purchasing. Simulation tools to represent circuit behavior, models to instantiate modeling tools, and information to decipher lead lengths and filtering within ICs all seem important data. It would be nice if I could capture all of this information into the component now while planning.
Capturing the Circuit With Smart Symbols
Much of the information for building prototypes and other circuits is part specific. Getting information into part symbols would b helpful in collecting diverse information about the part into one place. Instead, usually, I keep spreadsheets for the data most valuable to our specific work function as relates to each part. Prototyping is trickier as new information is trickling into each of our information storage systems, our directories.
When prototyping, I’m listing each part and its electrical characteristics. I spend time checking datasheets for design requirements validation before sending the schematic along for PCB layout.
The layout designers want the datasheet so they can make a partially smart symbol for their layout library containing footprint and dimensional information. Procurement wants the list of part and any vendors I’ve identified to prepare their sourcing spreadsheet with appropriate information. It would be great to collect each job function’s information in one place. How about we put it in the part symbol and make our respective spreadsheets from there?
Store comprehensive information in unified component symbols
Using Smart Symbols to Build Your BOM
My idea of a smart part symbol would have electrical information, vendor information, and distributor information. The electrical information would include parametric information, open-source simulation models, signal integrity models, and register transistor logic information as applicable. Vendor information would include the part number and associated datasheet. Datasheets contain not only electrical requirements but also manufacturing specifications for both assembling and ordering. Distributor information would include quantity, sourcing, and costing information.
Having all the information located in one part symbol in one library and accessible throughout the enterprise would free up valuable time to innovate and to prototype. Who wants to do paperwork when you can have your hands on parts and tools in the lab? A smart symbol would provide all of this. Having smart symbols instantiated into your schematic capture and layout tools allows generation of Bills of Material of the same prototype for different departmental functions.
Having the information in one place will free you up to stay in the lab, instead of preparing more documents. Having prototype material needs in one place answers questions for your partners without your presence required.
If you are wondering where you can get a such a Bill of Material for your prototype, it is ActiveBOM within the design tools of Altium Designer 18. Altium Designer 18 has a unified environment and its ActiveBOM is accessible from early schematic capture through the release of documents for prototyping.