The printed circuit board is a dielectric plate, where conductive circuit of an electronic circuit is formed on the surface by a volumetric form. Printed circuit board is used by electrical and mechanical way to connect and diversified electronic components.
Outputs in electronic components joined by soldering with a conductive pattern elements.
The electrically conductive pattern is made by foil on solid insulating. There must be holes for mounting and contact pads what enables mounting planar or pin components in each circuit board.
If the plate has multiple layers, it must have vias for electrically connecting portions of the foil, which is located on different layers of the board.
There is “solder mask”, which is a protective coating on the external side of the board. Also every board is required to be marked, so it must have text and auxiliary picture that is performed according to the design documentation.
Types of printed circuit board
Printed circuit boards can be divided into 3 groups:
1. Single sided PCB. The conductive pattern is on the one side of the insulating base. There are non-metallized through holes that occurs mechanical fixation. All printed conductors end pads, which are used for the connection. If there is a conflict of intersecting routes, it can be resolved by installing a curtain wire jumpers.
2. Bilateral board. Consist of a base, but the conductive patterns are made on both sides. If the electrical connections must be on both sides, the through-plated holes is used. When there is a conflict of crossing routes, we can move route bypassing the other side of the PCB.
3. Multilayer printed circuit boards. That’s a lot of thin insulating substrates to be coated conductive pattern, and then they are physically connected to one multi-layer substrate.
Electrical connections are made via the through or blind holes.
Each layer has its own function in the multi-layer boards:
The outer layers are used for mounting electronic components.
Signal layers are used for signal interconnection topology map.
Some layers are heat-align.
There is a power and ground layers. They have large polygons with minimal inductance and ohmic resistance. These layers are used as electric screens, buyout grounded for high frequency decoupling capacitance.
There is another classification of printed circuit boards. Depending on the complexity of printed circuit boards, is isolated:
Flexible printed circuit boards. They have a thin and flexible substrate. They are used to connect the various parts of electronic devices that run on a rigid base. Flexible boards are used as a base for the antenna, inductors, etc.
Flex-rigid printed circuit boards. They are both flexible and rigid boards simultaneously. They are very difficult to be made, therefore they may not make so many companies.
Board with non-through vias.
Metal Core PCB can be divided into such types:
Metal Core PCB. Are used when it is necessary to dissipate more heat output. To do this often use powerful SMD LEDs in such boards.
Printed circuit boards for high frequency applications. Used sverhvyvsokochastotnyh devices. For the manufacture of circuit boards using Teflon, PTFE and other materials.
PCBs for LED solutions. Used in LED technology.
Printed circuit boards HDI. They have a very high density of interconnections.
Colorless technology printed circuit boards. If you are prohibited from using materials that are harmful to the environment, then use these cards. Colorless technology printed circuit boards do not use lead.
2. Printed circuit boards for high frequency applications. It is used in devices with high frequencies. As a base used teflon, PTFE or materials based on politetraftroetilene.
3. PCBs for LED solutions. Used in LED technology.
4. Printed circuit boards HDI. Have a very high density interconnects.
5. Colorless technology printed circuit boards. Used when it is necessary to use materials that do not harm the environment. One of them is lead. Therefore, colorless technology printed circuit boards without lead.
Stages of development of printed circuit boards
PCB design is a long process and it consists of several stages. It is necessary to take into account the standard IPC, the requirements for the production and testing, as well as to analyze thermal operating mode.
Design specifications of printed circuit boards:
Circuit schematics (any format will apply).
List of components containing links to the manufacturing documents (datasheets) and reference designators (any format will apply).
PCB drawings specifying dimensions, configuration, mounting holes, connector and button locations, LED mount height, areas without traces, areas without components, areas with limited mount height etc. (any format will apply).
Information specifying trace features i.e. the number of layers, parameters of circuit groups (differential pairs, clock signals, high-voltage circuits, power circuits etc.), components with high power dissipation etc.
2. Create a library of components.
Planting shifted formatted according to standards JEDEC or IPC.
3. Preliminary component.
The components are arranged according to the requirements.Hard components fixed location. Proposals to change the dimensions of the printed circuit board accepted.Other requirements are discussed. At this point you can already see the 3D model of the motherboard. We agree with you all the details, get approval, s begin tracing boards.
Final component of elements.
Specify the parameters of the trace chains and rules.
Produced wiring runs.
5. Simulation of printed circuit boards.
Analysis of signal integrity;
analyzes electromagnetic compatibility;
performed thermal simulation;
analyzes of supply.
6. Verification of printed circuit boards.
Technical experts must conduct additional monitoring simulated device to reduce the number of possible errors.
7. Immediate delivery of the printed circuit board.
Execute all documents and files, and delivered to the customer.