PCB Layout

MAD PCB Layout Introduction


1. General

2. Outline Drawing

3. BOM or Part List

4. Schematic Drawing *

5. Netlist

6. Instructions

7. PCB design Rule Classification


pcb layout.png

                                                           PCB Layout Capture

1.  General

    • Mark all documents with date and reference number("yymmdd_Rev01")

    • Preferred format for drawings is .pdf

    • Preferred format for BOM is .xsl

    • Preferred format for instructions is .doc


2.  Outline Drawing


    • Show a top-side view. If required for clarity, add bottom and/or side views.

    • Show all dimensions for external perimeter and any internal cutouts.

    • Indicate the board thickness.

    • Show all board mounting holes. Indicate hole size or size of fasteners.

    • Show position of all fixed-location parts (connectors, LEDs, switches, etc).

    • Show all keep-out areas. Indicate the restriction type: "no parts, no copper, and indicate board

       side: top, bottom, both".

    • If tall components must be positioned to avoid interference with adjacent assemblies, add

   dimensioned height zones.


3.   BOM or Part List


    • List every part including electrical parts and non-electrical parts(heatsinks, etc).

    • Show manufacturer's complete part number, and indicate the manufacturer name for those parts  

      not found on Digikey / Mouser / Newark and other famous parts distributors' website.

 • Exception: common ceramic chip components may use "0402, 0603, 0805" in place of the complet

   part number.


4.    Schematic Drawing (click to to check)


5.  Netlist


    • Output a netlist from schematic tool. Preferred format is "PADS-Ascii" or "PADS-2000". Other

      formats can be converted.

    • If analog and digital grounds are to be kept separately and joined at a single point, ensure these 

       are shown as two separate nets.

    • Ideally, set your schematic tool to output manufacturer part numbers in the part description field. 

      Doing so will avoid having to update these fields   from the BOM later.


6.  Instructions

    • Drawings

       Confirm whether our standard drawings format is acceptable, or not. If not, please provide us

       your drawing template.


    • EMC

   If the assembly must meet emissions standards, the mitigation features must be discussed

   prior to layout. The positioning of circuit blocks is driven by several factors:

      (1) Schematic flow

      (2) Isolation/segregation goals

      (3) Specific customer requests

      (4) Realities of available area.

      If you want a specific layout, provide a simple block diagram.


    • Grounding

      Describe any special grounding requirements, especially single point grounding.


    • High Speed

      Describe any signal integrity requirements, such as differential pairs, matched lengths, and

      controlled impedance.


    • Isolation

      Describe any voltage isolation requirements.


    • Part Numbers

      Provide the board part number, assembly number, rev numbers/letters, and company name/logo.

      Unless otherwise specified, we place the   board part number in bottom side copper, the assembly

      number and company name on the top side silkscreen.


    • Safety

      If the board assembly will be used in any class of device for which specific safety criteria are

      mandated, need to provide the details.


    • Segregation

      Describe circuit segregation requirements, such as separation of low-level analog from noisy

      switching circuits. Identify sensitive circuitry and noise generators.


    • Test

      Decide whether the board must have 100% nodal test access for ATE.


    • Text Items

      Describe any text items to appear in silkscreen ink. Examples: connectors' pin 1, functional labels

      at pots, at option jumpers, and at connector pins.


    • Thermal

      Describe any thermal management requirements, such as heatsink areas for specific components.