Who simulates or protoypes their designs before doing a PCB ?

[gregebert]

Just curious to know how many of you run logic and/or analog simulations on your designs before doing a PCB, or if you do any prototyping.

Since I'm a longtime designer of IC's, I rely heavily on simulations: ngspice for the analog sections, verilog for the entire PCB (logic, FPGA if any, and analog). Once that is done, I go straight to PCBs with no prototyping. So far, I've only had 1 project that required any 'blue wires' to fix a design error.

[liam bartosiewicz]

I’ll usually use Falstad to simulate analog sections of circuitry and to test component values, but nothing for the digital stuff 

On Mar 23, 2024, at 8:41 AM, gregebert <greg...@hotmail.com> wrote:

Just curious to know how many of you run logic and/or analog simulations on your designs before doing a PCB, or if you do any prototyping.

Since I'm a longtime designer of IC's, I rely heavily on simulations: ngspice for the analog sections, verilog for the entire PCB (logic, FPGA if any, and analog). Once that is done, I go straight to PCBs with no prototyping. So far, I've only had 1 project that required any 'blue wires' to fix a design error.

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[Tom Nolan]

I've been using Proteus for many years.  I'm sure I've saved lots of money on wasted boards.  Also often see better ways of doing things while simulating.

Tom

On Sat, Mar 23, 2024 at 11:41 AM gregebert <greg...@hotmail.com> wrote:

Just curious to know how many of you run logic and/or analog simulations on your designs before doing a PCB, or if you do any prototyping.

Since I'm a longtime designer of IC's, I rely heavily on simulations: ngspice for the analog sections, verilog for the entire PCB (logic, FPGA if any, and analog). Once that is done, I go straight to PCBs with no prototyping. So far, I've only had 1 project that required any 'blue wires' to fix a design error.

--

[gregebert]

I've heard of Proteus and Falstad, but never looked into them because I'm entrenched in my current suite of free CAD tools and so far I havn't seen anything that will nudge me out. The biggest fear I have is that a tool will get abandoned, so having them installed on my local system is a must. So far, the gEDA tools haven't been abandoned yet, but it's been a few months since the latest update. 

[Dekatron42]

I sometimes use LTSpuce for analogie simulations where many different positive and negative voltages are present as my skills ate inferior when it comes to electronics, I especially did this when figuring out how to design coupling stages and driving stages for the A-201 Polyatron some years back.

/Martin

[Grahame Marsh]

I am a chemical engineer and when I retired I was working on the safe landfall of north sea oil and gas. I have little formal electronics training and I'm mostly self taught.... That said....

 I do a mixed bag of experiments using dead insect on a copper sided PCB, a plug in board, a literal breadboard (mostly for valves), strip board when I want something semi-permanent or for a long running experiment and simulations using LTSpice. I tend to do what I think is best at the time for the tests I want to perform. I do enjoy building things, this is the hobby after all.

My use of LTSpice is limited to analogue stuff and some power supply simulations. I've not had too much success with designs that use inductors in particular. But I spent some time simulating various CRT deflection amplifier designs before moving to a PCB and I was not disappointed by the results. I know I should simulate more before heating up the soldering iron...

For PCB design I own an unlimited copy of Eagle 7.7.0 which was the last version before they went subscription based. It is getting old now (like me) and I have looked at some of the all-in-one design software but Eagle does what I want (schematic to Gerbers), I know how to use it and I have a large component library that I have developed myself. So I don't feel a need to go anywhere else: I am unconvinced that the facilities in any new software would be repaid the time I would spend learning how to use it. But my prototype PCB designs often have problems: they tend not to be "electrical" but "mechanical" in nature. Components are too close or I goof with the silkscreen such as I label things incorrectly - this is just incompetence I know.

Going back to the simulation question - I started with QUCS and then moved to LTSpice - should I look to use another simulator? What should I look at beyond LTSpice?

 Keep in mind my limited knowledge of electronics and the need to self-teach!

Grahame

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[gregebert]

I tried LTSpice 10-12 years ago because it has models of many of the IC's from Linear Tech; a lot of other IC manufacturers dont supply models at all, or only with an NDA. It's a great tool, but I generally dont use it because it's PC-based, rather than Linux, which I use for my other design work. I may give it another try if I mount a Linux disk onto the PC (so far I have not, largely out of security concerns; my PC is more likely to get hacked than my Linux machines, and having a pathway between them makes things less-secure).

The other reason I used LTSpice was that I could run sims during work breaks; my employer's firewall blocked remote access to my home network. But, that problem has been solved because I'm now retired.

Netlisting out of your schematic-capture tool, rather than from LTSpice, and into your simulator (SPICE, Verilog, etc) is a good way to catch design-entry errors that can sneak into your PCB layout otherwise undetected.