Electronic Design Checklist

I can't point you to a list, but I can tell you the rule of "bypass caps on each IC" is pretty obsolete. That actually comes from the days of double sided boards with power traces. A bypass cap had to be on each chip, which meant, from pin 8 to pin 16. Yeah, that old!

In reality, power distribution design is a whole topic, vastly more complex than the "cap on every power pin" rule. Your power distribution system should have a design process and a write up that describes how you made your decisions. Many designers don't have a design process other that "a cap on every power pin". Their designs may work, but when designing high volumes, power supply distribution should be cost optimized just like everything else.

We have an extensive checklist that we run before we release a PCB for production, but it's more about the board layout than the schematic-level design. I'll see if I can get permission from The Brat to post it here.

It would be far more difficult to make a checklist for the electronic design. We have design reviews for that: PDR, CDR, and lastly PCB, and lots of brainstorms and informal meets. We have a PDR, preliminary design review, this afternoon, for a new power supply board. The input is the first-cut schematic and the draft manual.

I don't use any DRCs in a PCB layout program, past the obvious clearance and connectivity checks. Too much trouble to set up, too dumb to be much help. About all a schematic program can do is find single-ended nets.

This new board has one blue-wire ECO. One FPGA pin won't do the SPI function it was assigned to. Humans have to check stuff like that.

It's astounding how much you have to know to design serious electronics now. That's probably why kids these days prefer FPGAs or software, which are clearly bounded and more intellectually pure, ie easier.

It often tends to pay better, too. It's also astounding how many start-ups who'd gladly pay a software engineer whatever, turn up their noses at what "serious electronics" costs to do.

I run away from start-ups who are doing projects that involve both software and hardware and are giving the software guys free spa days while treating the hardware side like an afterthought (we'll just outsource that)

Because too many designs, now, treat entire "systems" as COTS "components". Buy a little board that has features X, Y and Z -- even if it also has Q and W (that might be unneeded).

I am always amazed at how folks will convince themselves to buy a "module"... and then design another card that addresses the parts that the module doesn't. So, you're still designing a PCB, have likely complicated the packaging (or, restricted your choices concerning it) AND are reliant on a more complex component -- which likely isn't completely documented nor guaranteed not to change in some meaningful way -- that could become unobtainable, overnight (as many of the modules are sourced from small shops)

But, people are of the mindset that hardware can be "canned" and neglect to discipline themselves to treat software similarly; they (largely) approach it as "ground up" for each project! (I chose my projects to leverage past designs heavily; I only want to deal with a small part of a design's uniqueness, not treat everything as novel!)

We do sometimes use a MicroZed board as a plugin assembly. It does a lot of tedious stuff, but more importantly we can get them.

We also use some LCD eval boards as displays, because we can get the evals but we can't get the chips on them.

Going back to Mr. Larkin's comment about "It's astounding how much you have to know to design serious electronics now" some potential clients seem to want one to be both a hotshot circuit designer and a hotshot PCB layout person also, which IMO is asking a lot.

I can understand the perspective that the person who designed the design is sometimes the best to lay it out, but still.

Particularly frustrating in a few cases I've had where I've told the potential client "Yeah I have a past design that I can modify to suit your requirements no problem, can have you up in running in no t..."

"We need the absolute best production-cost-optimized PCB for it, also."

"Well I'm probably not the best person to do tha.."

"Ok, not interested we'll look elsewhere."

And then some time later they're still looking. Meanwhile they probably got nine coders on staff.

I also see it's pretty common in this area for various companies to have open positions for "Senior Hardware Dev" that go unfilled for months or years.

I should probably just raise my price, use the extra to hire someone to assist me myself and shut my mouth about it, huh... :)

I've typically left (production) layout to someone who does that exclusively. They know what their pick-n-place kit's restrictions are, how they like to panelize boards, the sorts of test fixtures they'll want, packaging details (which will likely change) etc.

I layout prototypes (simply because its easier to prototype in foil than any other technique) as an expedient -- no need to wait for the client to develop "proper" schematic symbols, PCB footprints, etc. And, I can put in any "hooks" that *I* might think helpful (which may well be elided in production).

IME, the more effective combination is hardware-software codesign (not hardware and layout). Designs wherein the hardware and software were independently (orthogonally) created often have clumsier implementations.

E.g., I designed a removable sensor array in a product. I wanted the software (which I was also writing) to be able to detect when the array was "not connected", connected but one or more sensors shorted -- or opened, etc. And, not spend any recurring dollars to do so!

Hardware is cheap. Spend your time coming up with ways to cut software development and maintenance costs (assuming most products have software in them). And, other "support" costs (e.g., depot repair).

E.g., if someone is going to have to look at a unit after the sale, that's a $100+ hit to profit (or, adder for the customer's TCO)

ALWAYS the best approach. I've had folks balk at some of my estimates. No, I'm not going to "rethink them" with an eye towards cutting YOUR cost. Find someone else who is "less expensive" (or, more efficient OR less accurate in their estimating). And, if you are honest with yourself, you'll look at those actual costs to see if you're decision making process is in need of review.

Hardware is seen as easier and a "one time" process. A hardware revision is almost always to fix a fuckup (in design, use or supply). Software is also, often, for "fixes". But, also, for *enhancements*. It is not uncommon to release a product with a plan in place as to how to evolve the implementation, over time. If you have to swap/add boards, then it's costly.

So, you want (need?) *one* guy who can tackle all of your imagined needs. In practice, its usually easier to outsource that, as req'd.

I have a buddy that I always sub work for low noise analog design. OTOH, he calls me for anything digital/integrated. We're each capable of doing both. But, have more expertise in our own little domains and the trust we share means it is easy to sub portions out -- without long negotiations, etc.

In my experience, the best PCB designers have been women who didn't understand electronics.

If you can raise your price, why haven't you done that already?

As to hiring someone, I was working at a defense contractor making two way radios. We were adopting some four letter abbreviation for hardware that the software guys already used a three letter form of. We were writing our justifications for our estimates and we pretty much all added time for dealing with the paperwork of this new paradigm. We got yelled at for adding time for this, because if it took more work, something was wrong. It was supposed to let us work more effectively. This company had grown so fast, it essentially had become a new company, a young company, and few people knew how to bid the durn thing.

My point is, if you have to raise your price to hire someone, maybe that's a mistake.

I will say it is seldom a good idea to say you can't do something, unless it really is not something you can do. I try not to shy away from learning opportunities if I think I can learn how to do it.

Thank you. I understand and agree with how much one has to know. I also agree about human eyes and brains on the design. My goal for seeking checklists is to help guide thinking. My undergrad courses were geared to both understanding and applying all the design equations and 'theory' as well as the practical aspect of actually building things. Grad school was all about theory. My first exposure to designing and building real boards & systems met with 'looks good on paper but doesn't work on the wirewrap/proto board.'...An older experienced EE explained some of the realities. I, in turn passed on my learning and experiences to new EE's. I also understand the complexity factor has been ratcheted up since my hands on design days, that I why is posed the request. My last real boards was a amd 29000 bit-slice cpu used for jet engine simulation. Learned some interesting things about dynamic RAM on that one.... Thanks for the insight. BTW, I worked in a small group of both hardware EEs and Sw engineers. We found that intense design reviews caught both design and potential implementation problems. Things worked well for the most part. One day we hired a EE who 'knew everything' and our design reviews turned into him always knowing better and not dealing with the design at hand. Some points were valid, most were to show how smart/clever he was. During that time, I was fortunate enough to learn some of the 'art' of electronics as well as behavior aspects of certain components. (Also learned that data sheets are not always correct - imagine that). j