5 ms·

PCB layout is as much art and black magic as it is science. I'm not sure why you dismiss the complexity so easily, this definitely is not just a matter of apply

PCB layout is as much art and black magic as it is science. I'm not sure why you dismiss the complexity so easily, this definitely is not just a matter of applying Maxwell's equations.

0_____0 1y ago
Layout is a puzzle, especially with particularly high density layouts, but some of this is ameliorated by high layer count and fine trace/space boards becoming cheaper. Definitely not black magic. RF layout is black magic, let's not steal their thunder here.
- tuetuopay 1y ago
  High speed PCBs are RF. At high enough frequencies, traces become waveguides, and the result cannot be predicted analytically. Simulation is your only light in this mess.
  - 0_____0 1y ago
    I have been lucky to not have to lay out anything that had frequencies of interest over 1Ghz or so. What's your experience been? E.g. types of signals, frequency range, issues you ran into?
    - fxtentacle 1y ago
      Signals that arrive faster than what the speed of light should physically allow for that trace length because you made the corners too sharp and then instead of flowing along your path the electricity creates a magnetic field which then induces a current and that allows the signal to tunnel through non-conductive walls. High speed boards cannot be simulated well. Because they are far from deterministic. That's what makes them so different from coding.
      - 0_____0 1y ago
        What was the context you had that issue in? RAM bus?
- numpad0 1y ago
  It's just across-modal. The list of components are linear list, connections between components are graphs, placements are geometrically constrained, and overall shape is both geometric and external to the board. So you can't just mechanically derive the board from mere linear textual descriptions of it. A lot of automagic "AGI achieved" LLM projects has this same problem, that it is assumed that brief literal prompt shall fully constrain the end result so long it is well thought out. And it's just not how it - the reality, or animal brains - works.
  - 0_____0 1y ago
    You need a LOT of context about what the components are and how they're being used in order to route them. Extreme case is an FPGA where a GPIO might be a DAC output or one half of a SERDES diff pair.
    - numpad0 1y ago
      Doesn't even have to be that extreme: there is no way port placements of a Mac Mini can be mathematically derived from a plain English natural language prompt, and yet that's what they're trying to do. It's just the reality that not everything happen or could be done in literal languages. I guess it takes few more years before everyone accepts that.
      - bb88 1y ago
        There's nothing new in EE under the sun. Hasn't been for 40 years really. EE's min/max a bunch of mathematical equations. There's a lot of them, but it's not nearly as difficult as people think it is. They end up being design constraints, which can be coded, measured, and fed back into the AI. It's not even been three years since Github Copilot was released to developers. And now we're all complaining about "vibe-coding".
        0_____0 1y ago
        Design constraints that have so many factors that people still don't use autorouters for most stuff. You're not getting it, drawing the wires isn't the hard part, understanding the constraints is.

PCB layout is as much art and black magic as it is science. I'm not sure why you dismiss the complexity so easily, this definitely is not just a matter of applying Maxwell's equations.

0_____0 1y ago

Layout is a puzzle, especially with particularly high density layouts, but some of this is ameliorated by high layer count and fine trace/space boards becoming cheaper. Definitely not black magic. RF layout is black magic, let's not steal their thunder here.

tuetuopay 1y ago
High speed PCBs are RF. At high enough frequencies, traces become waveguides, and the result cannot be predicted analytically. Simulation is your only light in this mess.
- 0_____0 1y ago
  I have been lucky to not have to lay out anything that had frequencies of interest over 1Ghz or so. What's your experience been? E.g. types of signals, frequency range, issues you ran into?
  - fxtentacle 1y ago
    Signals that arrive faster than what the speed of light should physically allow for that trace length because you made the corners too sharp and then instead of flowing along your path the electricity creates a magnetic field which then induces a current and that allows the signal to tunnel through non-conductive walls. High speed boards cannot be simulated well. Because they are far from deterministic. That's what makes them so different from coding.
    - 0_____0 1y ago
      What was the context you had that issue in? RAM bus?
numpad0 1y ago
It's just across-modal. The list of components are linear list, connections between components are graphs, placements are geometrically constrained, and overall shape is both geometric and external to the board. So you can't just mechanically derive the board from mere linear textual descriptions of it. A lot of automagic "AGI achieved" LLM projects has this same problem, that it is assumed that brief literal prompt shall fully constrain the end result so long it is well thought out. And it's just not how it - the reality, or animal brains - works.
- 0_____0 1y ago
  You need a LOT of context about what the components are and how they're being used in order to route them. Extreme case is an FPGA where a GPIO might be a DAC output or one half of a SERDES diff pair.
  - numpad0 1y ago
    Doesn't even have to be that extreme: there is no way port placements of a Mac Mini can be mathematically derived from a plain English natural language prompt, and yet that's what they're trying to do. It's just the reality that not everything happen or could be done in literal languages. I guess it takes few more years before everyone accepts that.
    - bb88 1y ago
      There's nothing new in EE under the sun. Hasn't been for 40 years really. EE's min/max a bunch of mathematical equations. There's a lot of them, but it's not nearly as difficult as people think it is. They end up being design constraints, which can be coded, measured, and fed back into the AI. It's not even been three years since Github Copilot was released to developers. And now we're all complaining about "vibe-coding".
      - 0_____0 1y ago
        Design constraints that have so many factors that people still don't use autorouters for most stuff. You're not getting it, drawing the wires isn't the hard part, understanding the constraints is.