basic constraints pcb designing
Hello....
There is lot of issues in PCB Design,most of them can be understood by experience....for beginner point of view these are PCB layout Basic guidelines
>It is often a good idea to have made a prototype circuit using point-to-point construction or wire wrap, as you will have solved certain basic issues to do with component selection.
>Consider physical constraints on the assembled board's size and heat dissipation requirements; choose your heat sinks if needed.
>Consider carefully the physical size of the components you are laying out; the circuit schematic doesn't tell you this. Equivalent components often have different packages.
>How do the components attach to the board? Are they surface mount components? or do they require holes, screws, washers, etc?
>Are there mechanical parts directly mounted to the board? eg: switches or variable resistors?
>How will the board mount in its container? What stresses (shock, strain, shear) will there be upon it and upon components?
>How will the board connect to its power source? What other connectors will be required (e.g: signal inputs, outputs)?
>Use construction paper and a pencil and sketch the board in its actual size; or use component layout software that includes information about the component outlines.
>Decide appropriate widths for each of the signal traces; this depends on the current each trace is expected to carry.
>Decide whether you will have a single-layer board, 2-layer, or multi-layer based on the circuit complexity and fabrication costs.
>Begin by placing component outlines, then by placing signal traces; leave a little room around each for tolerances.
>For a single layer board, spend more effort to avoid having traces cross each other; play with component placement or run traces underneath components; sometimes a jumper wire is needed.
>In 2-layer and multilayer boards simply run the traces on different layers, and use plated-through holes to jump from one layer to another.
>Try to predict and avoid assembly errors: where there are multiple components of the same kind, or where pins have a polarity (eg: electrolytic capacitors), try to place them in parallel and orient the positive pin in the same direction.
>If your PWB design software has a DRC (design rule check), use it.
If u r designing PCB layout with RF circuits on a 2-layer or multilayer board these are some helpful guidelines....
>Identify the critical parts of the circuit and lay them out first.
>Have one of the layers act as a continuous ground plane.
>If signal traces are constant width and height above the ground plane, and are properly terminated, then their characteristic impedance is more well-behaved and may be calculated.
>Avoid sharp corners.
>Keep signal traces and component leads as short as possible.
>Inputs and outputs should be far apart, so that RF energy will not leak back from output to input. stages should line up, rather than snake around.
>Decouple the RF parts of the circuit from the DC parts of the circuit.
>Shield AF and IF components from RF components.
I think this will help u little bit,if Yes click on Helped.......