PCB Kingtech continue with the basics of pcb design. Before validating the BOM file, be sure that all active parts
are in the file. Parts should be validated in accordance with those fields as follows:
Serial number.
Part description
Designers that match the schematic
Quantity of the components
MPN
VPN
DNI (do not install) components
BOM or bill of material (BOM)
A good example of BOMs. BOM
Stack-up preparation in PCB design
Stack-up is an essential feature in the fundamentals in PCB design. It defines the layout that a multilayer board is
constructed in a sequence fashion. Stack-up gives information on the weights of copper and the thickness of
the material which are essential for the manufacturing of circuit boards. If boards are properly stacked with
precision, crosstalk and electromagnetic emissions are minimized, and quality of the signal is enhanced.
Be aware of your board's mechanical limitations that include the thickness of the board and the height of your
components. It is essential to know the control impedance requirements as well as the number of differential
pairs as they will affect how many layers are on your board. The density of routing on the circuit board will affect
the amount of layers. Select the PCB material according to the speed of its rise time.
PCB stack-up
The typical PCB multilayer stack-up
Check the manufacturing quality of your stack-up with our free Stack Up Planner. The following requirements are
essential for the plannerto work:
The PCB material (FR4 I-Speed, FR4, Rogers, etc.) is dependent of the frequencies required as well as the
surrounding environment.
Layers that include power and signal layers. These include power and signal.
Imperative requirements for Impedance, like 500 single-ended, 900 differential or 1000 differential
Copper thickness (1/2, 1 or 2 pounds)
Stackup Planner by Sierra Circuits
Take care to inspect the footprint you have created
Schematic, BOM complete, and stack-up comprise the core on the circuit board. It is much easier to make
footprints for specific components when they are included in standard packages. Most of the time footprints for
standard programs are included within the library of the software (Altium Designer, Allegro, etc.). If not, you'll
have to build it from the datasheet for the component.
Make sure that library components conform to the recommended land pattern as described on the information
sheet. After designing your footprint, do a quality check. Mark your component orientation. Footprints should be
checked for bottom and top view, as well as pin pitch and the height. Making sure that you have a precise
footprint in line with the pattern of the land will prevent problems when assembling.
To determine the right part and the land pattern it is crucial to use the correct numbering key from the
datasheet. Incorrect reading of the sheet can cause a wrong footprint, which could require complete re-design
and fabrication for the board.
The image below shows an illustration of a key that is numbering as well as a range of footprints.
The numbering key is located in the footprint.
The numbering key is contained in the datasheet
Model numbers for Footprint and the associated PINs
A chart displaying the model numbers as well as their associated Pins
Installation of components
Once the design and mechanics of the board are done, the next step is to install components. A proper
placement of components on a PCB results in higher performance and better signal quality. It begins by placing
the components placed in the exact spots in accordance with the design specifications. They typically consist
of connectors as well as their related components. After that, the major components, such as processors,
memory and analog circuits are put in the correct positions. The next step is placing additional components like
crystals, capacitors for decoupling, along with series resistors.
Also, read How to place components in KiCad
Be sure the mechanical drawing shows the location of mounting holes as well as other parts that require critical
locations and rotation. Make sure to check if the drawing contains any height limitations on the top and bottom
sides.
The basics of the placement of components on the PCB
Properly placed components should be placed on PCB
PCB routing
The process begins by establishing the design guidelines for the physical space and impedance regulations. The
calculation of the width of the trace is to be determined according to the demands of the various circuits. Give
appropriate rules to the nets according. Every trace that is controlled should have an uninterrupted reference
plane layer.
The procedure of routing involves placing copper traces between nodes. The conductive path is determined by
the positioning of traces, vias and arcs which connect the nodes. Following the routing, power/ground
connection to the plane is established
High-Speed PCB Design Guide - Cover Image
High-Speed PCB Design Guide
8 Chapters - 115 Pages - 150 Minute Read
WHAT'S INSIDE:
The reasons for signal integrity issues
Knowing transmission lines, and controlling impedance
The selection process for PCB materials with high-speed speed
High-speed layout guidelines
DOWNLOAD NOW
PCB fabrication diagram
A well-designed fabrication design will save time, cut expenses, and ease the burden. The drawing of fabrication
contains details about the manufacturing process and the mechanical aspects of the circuit board. It contains
information on stack-up as well as fabrication notes, IPC standards, and notes on impedance.
The drawings of fab are provided as PDFs to the manufacturers. The fab drawing must contain all the details
needed to make a piece of board. It must mainly comprise of:
Dimensions of the board
The outline of the board
Chart of drilling
Drawing Stack-up
Copper trace and tolerance to etching
PCB fabrication diagram
A sample of a fabrication drawing
Drawing of the board assembly
The PCB assembly drawing has all the details necessary to construct the board. This drawing is available in pdf
as well as .jpg format and could include component outlines, surfaces pad and through hole pads, as well as the
polarity mark title and outline of the board.
In addition, the assembly drawing is composed of several key components such as:
Component outline: Be sure you display all the components' shapes as well as their respective reference
numbers to be soldered. Also, include components that will be press-fitted or affixed with mounting hardware.
Views of additional views on double-sided boards typically require a view of the front as well as the
backside. Both views are possible on one sheet if your PCB is small. Otherwise it is necessary to add more
sheets.
Manufacturing labels: identifying manufacturing labels like barcodes or assembly tags using the help of a pointer,
and then linking them in notes.
Assembly notes: They are a collection of instructions with assembly information as well as the industry's
standards and requirements, as well as particular location for the feature.
Final QC and exporting right Gerber files
After the layout is completed, the last stage is to perform a set of tests. In this phase, DFM (design for
manufacturability) is conducted to determine the fundamental issues that are associated with the layout. These
tests will identify the possibility of issues occurring during the manufacturing process. With the Sierra Circuits
superior DFM software, users are able to test the manufacturability of your design. The designs (in the format of
Gerber) are scrutinized and the details of any design rule violations are displayed.
Better DFM by Sierra Circuits
The final list of deliverables must include all gerber files including assembly and fabrication diagrams, the drill file
ODB++, IPC-356 and X-Y positioning files to be used in assembly. With this information, your fabrication
company is able to perform designs for manufacture (DFM) along with design for assembly (DFA) tests using the
board.
Please let us know in the comments section if your desire to know more about designs for PCBs, production and
assembly. PCB kingtech will be more than happy to assist you.
