How to learn PCB layout?
Learning PCB Layout requires at least a few points:
(1) Understanding the basic principles of the circuit, you can refer to the "Basis of Circuit Analysis".
(2) Choose Design tools, recommend cadence, I have used AD, personal feeling or Cadence more powerful handy. I don't know how to define a cutting-edge PCB. In fact, the most challenging part of a PCB is the contradiction between design and cost Fab capability. There are dozens of layers of PCB (the most 48 layers, the least 24 layers), small pin pitch, narrow wiring space, stringent signal quality requirements, and heavy workload. The trivial routing constraints, after completion, there are a number of checks, and I believe that the Cadence to complete these tasks will be more convenient and easy.
(3) It's very important to draw a schematic diagram by cadence. If you don't know the circuit principle, it's very difficult to make a good Placement (I don't know if the term is universal, so I'll explain: the actual layout of the schematic devices in PCB).
I think a good Placement actually completes more than half of a PCB design.
(4) According to the schematic diagram, we will make good use of PCB space and make reasonable Placement to ensure the best signal path and the largest signal routing space. After the Placement, adjust the silk, which is the face of the final board.
(5) PCB stackup will be designed, which is reasonable and optimal (without sacrificing signal quality, considering both cost and routing complexity, because the more affirmative layers the better, but the higher the cost). Design routing constraint rules, and then complete Layout.
(Personally, I think Layout is the simplest in this whole process, because under constraints, with a little experience, the final layout can be completed.)
(6) Knowing the actual Fab capability of the manufacturer, of course, you have to know whether your PCB can be made and whether the manufacturer can produce it (if you design a 100-layer board (even if it is estimated to be sky-high price). I don't know which manufacturer can generate it. At present, I know that the most Fab around you is 60-layer (40x60cm 10W dollars), and also. I haven't heard of the 70 layers.
(7) Will make quotation, know the charge of each Fab, stack, blind hole, buried hole, plug hole, back drill, processing accuracy, drilling ratio requirements, line width, etc., can estimate the quotation at the beginning of the schematic diagram, and even take the cost into account in the design, so that the final product has price competitiveness.
(8) PCB will be checked after completion, including impedance matching equal length line width check, power line load capacity check, repetitive routing check, short circuit break check, signal return path check and so on, as well as the actual Fab ability check, line width check, line spacing, line hole spacing and so on.
(9) Fab files are generated and manufactured by Fab manufacturer.
(10) There is still one thing missing from the above. In terms of BOM option, according to the schematic diagram, considering the cost supply cycle of devices, the impact on Placement (if all the resistors are of the same parameters, in most cases I would like to choose the smaller size, because it can save PCB space) and choose the most suitable device.
