For my next installment on the E14: DIT blog, I wrote an article with some of my most useful steps to completing a schematic review. I’ve found these to work great on big reviews that involve lots of people as well as small reviews that consist of just me and the designer. Check out the full article and leave a comment with your thoughts!
My Review Process
Labeled ‘my’ process because asking an engineer to use another person’s process is akin to proposing a wife-swap. Some people may be into it, but it is generally a weird, horrible idea. However if you’d like to use some of the steps my process and I employ, it just might make you better with your process.
- I spend time to gain an understanding of the system and the requirements.
Sometimes this includes a few discussions with the designer. Since he or she knows more than I do, I am strictly trying to get a grip on how the part was designed and never bring up criticisms. Once I know how it was intended to work I will independently examine the design to come up with well thought out criticisms and corrections for the review meeting.
- Using the block diagram and my understanding, I write a list of things that need to be checked to guide my organization.
I will decide my favorite circuit flow and write a list of subsystems to check based on the block diagram ensuring that I will leave no part or section unchecked.
- Next comes the ‘meat’ of the review. I go through each block, part by part, and ask myself, “If I needed to use this part to complete this job, how would I design it?”
It is important to write each question, answer, and calculation in the notebook since it will likely come up more than once. Also, small notes, problems, and questions for the designer should be written in red so they are not missed. At the very least, I find myself asking the following questions:
a. Check each pin on the part. Is it going where it should? Searchable PDFs are great for finding all instances of node names.
b. Check all of the supporting part calculations. Time constants, resistor ratios, etc…
c. Are the power rails connected correctly with proper decoupling?
- Look back through the schematic and the organization list (from step 2) to be sure every part, connection, and functional block has been checked. I am always amazed at how many parts I would have missed without this step.