RF Circuit Construction - Part 1 - Radio Design 101 Appendix C

[@johnwest7993]

I stopped making my own PCB's partly because of the low price and fast bd turnaround time these days, but mostly because the mix of digital, audio, and RF on so many bds these days causes me to start my designs with 4 layers. I have a + supply inner layer, a Ground supply inner layer, the digital layer on the outside of the + supply layer, and the analog or RF on the outside of the ground supply layer. But that's just a starting point. I may have to add more layers for multiple power supply voltages or isolation of analog and digital grounds. The need to eliminate noise signals on modern bds simply goes almost immediately to the need for multi-layer bds. So I'm very glad for reasonably priced quick-turnaround bd houses. A prototype built using any other technique simply wouldn't adequately reflect what a modern circuit design is intended and required to do. As I tell new PCB designers who lack detailed electronics knowledge, every trace is a transmission line, and every signal is radiated.

[@MegawattKS]

It is amazing how low-cost boards have become, so as you said, 4-layer is almost the new standard. It depends on the circuit/project/product of course, but the thin 5'ish mil thickness from top to internal-1 ground plane helps tremendously. Fortunately for a lot of designs - which may still use chips with digital edge speeds of a few ns, transmission lines may not have to come into play (except for long signal runs of course). Interesting subjects. Thanks for leaving a comment.

[@W1RMD]

Excellent presentation! I really love those "groovy" 1960's circuit boards.

[@MegawattKS]

Well put ! Definitely a 60's vibe on that computer card. They give meaning to the layout term "artwork" 🙂

[@ЕвгенийШепард-р2х]

Super! Thank you for your job!

[@MegawattKS]

You're welcome! Glad it was helpful.

[@ernestb.2377]

Hi. Great lesson once again! Thank you. One typo @28'31" Xc --> XL

[@MegawattKS]

Thanks! Good catch. Thanks for letting me know. Wish I'd seen it earlier. Sadly KZbin doesn't allow delete/replace edits. But fortunately it's a blatant enough typo to not mess up the message 🙂 I'll try to update the slides on ecefiles.org with the edit today. (For others if they look for it, it's at 5'11'' on the "Why it Happens" slide)

[@ernestb.2377]

@MegawattKS oh, it is an "innocent" little mistake with no impact. People who watch also need to stay sharp a bit 😁

[@dustinl5372]

At the beginning of the video there is two opamp symbols at the bottom with two different labels. They caught my attention. Interested in knowing how to protect from the use.

[@MegawattKS]

Sorry - I didn't elaborate those blocks. The triangles are meant to be just some amplifier or other RF circuit with input and output impedances (not opamps). It's an abstract schematic and will be used in part2 of the video.