There are wiring on both sides of the dual layer PCB, but to use the wires on both sides, you must have a proper circuit connection between the two sides. This "bridge" between circuits is called a via. A via is a small hole filled or coated with metal on the PCB. It can be connected to the wires on both sides. Because the area of the double-sided board is twice as large as the single-sided board, the dual layer PCB solves the difficulty of wiring interleaving in the single-sided board (which can be conducted to the other side through the hole), and it is more suitable for more complicated circuits than the single-sided board.
SPEEDAPCB is a professional PCB supplier. We can provide customers with a one-stop service from PCB design to PCB production and assembly.
As a professional PCB manufacturer, we have 10 PCB production lines to manufacture double sided PCB board prototype. The machine works 24 hours a day, only to provide customers with satisfactory delivery time.
Our PCB boards can be divided into single-panel double-panel and multilayer boards according to their structure. The double sided PCB board is a board with double-sided wiring on the board. An important feature of the double sided prototype PCB is that it has a guide hole to connect the wires on both sides into a circuit.
The double-panel wiring can be staggered with each other, which is the biggest difference from a single-panel; the double-panel is more suitable for complex circuits and has a wider range of use.
The cost of single and double panels is not much different. If there is no special requirement, all industries will give preference to double panels; after all, the performance and stability of double panels are better than single panels.
|Number of Layers||Double Side|
|Surface finished||Gold Plating|
|HAL Lead Free|
|Hot Air Solder Leveling(HASL)|
|Entek Coating (OSP)|
|Solder Mask||Any color Green, White,Black, Yellow, Red, Blue|
|Other printing||Gold Finger|
|Carbon Print, Peelable Mask|
|Solder Mask Plugged Hole|
|Copper thickness||1/ 2 oz (18 um) - 4 oz (140 um)|
|Min. Finished Hole Size||0.3mm(12mil)|
|Hole Size Tolerance (PTH)||+/ -0.076mm (3 mil)|
|Hole Size Tolerance (NPTH)||+/-0.05mm (2 mil)|
|Min. Line Width and Spacing||0.10mm (4 mil)|
|Min. Solder Mask Clearance||0.076mm (3 mil)|
|Min. Annular Ring||0.1mm (4mil)|
|Profile and V-Cut||CNC-Routing, Stamping and Beveling, V-CUT,CNC|
|Special Process||Micro-section, Chamfer for Gold Finger|
|Testing||Electrical Testing, Controlled Impedance Testing, Flying Probe Test, X-Ray Inspection AOI Test|
|Environment||Clean room environmen , Dust-free workshop|
|Transportation||Fedex, DHL, UPS, etc.|
|Files||Gerber ,Protel ,Autocad ,Powerpcb, Orcad, etc.|
Dual layer PCB, also called double sided board, it has wiring on both sides. But in order to use the wires on both sides, there must be a proper circuit connection between the two sides. This circuit between the "bridge" is called a guide hole (via). Guide holes are in the dual layer PCB, filled or coated with metal holes, which can be connected to the two sides of the wire. Because the double sided panel is twice as large as the single sided panel, the double sided panel solves the difficulty of interlacing the wiring in the single sided panel (you can pass through the hole to the other side). Dual layer PCB is more suitable for use in more complex circuits.
To get the best performance of electronic circuits, the layout of components and the layout of the wire is very important. In order to design a good quality and low cost PCB, the following general principles are suitable for single sided PCB design and dual layer PCB design.
First, consider the size of the dual layer PCB.
PCB size is too large, the printed lines are long, the impedance increases, noise resistance decreases, and the cost increases; too small, it is not good heat dissipation, and the neighboring lines are vulnerable to interference. After determining the size of the dual layer PCB, then determine the location of special components. Finally, according to the functional unit of the circuit, the layout of all components of the circuit.
The wiring principles of dual layer PCB design are as follows.
1. The wires used for the input and output terminals should avoid adjacent parallelism as much as possible. It is better to add interline ground to avoid feedback coupling.
2. Printed wire corners are generally taken rounded, while right angles or pinch angles in high-frequency circuits can affect electrical performance. In addition, try to avoid using large-area copper foil, otherwise, when heated for a long time, the copper foil is prone to expansion and shedding phenomenon. When a large area of copper foil must be used, it is best to use a grid shape, which is conducive to the exclusion of volatile gases generated by the heat of the adhesive between the copper foil and the substrate.
The center hole of the pad should be slightly larger than the device lead diameter. The pad is too large to form a false solder. Solder pad outer diameter D is generally not less than d + 1.2 mm, where d is the lead aperture diameter. For high-density digital circuits, the minimum diameter of the pad can be d + 1.0 mm.
Dual layer PCB has the following functions in electronic equipment:
(1) To provide mechanical support for fixing and assembling various electronic components such as integrated circuits, to realize the wiring and electrical connection or electrical insulation between various electronic components such as integrated circuits, and to provide the required electrical characteristics.
(2) To provide solder resist graphics for automatic soldering and to provide identification characters and graphics for component insertion, inspection, and maintenance.
(3) Electronic equipment using dual layer PCB, due to the consistency of similar printed circuit boards, to avoid errors in manual wiring, and can achieve automatic insertion or placement of electronic components, automatic soldering, automatic detection, to ensure the quality of electronic products, improve labor productivity, reduce costs, and facilitate maintenance.
(4) Dual layer PCB provides the required electrical characteristics, characteristic impedance and electromagnetic compatibility characteristics for circuits in high-speed or high-frequency circuits.
(5) Dual layer PCB with internally embedded passive components provides certain electrical functions, simplify electronic installation procedures, and improve product reliability.
(6) In large-scale and ultra-large-scale electronic packaging components, dual layer PCB provides an effective chip carrier for miniaturized chip packaging of electronic components.
Dual layer PCB is a printed circuit board with copper on both sides including Top (top layer) and Bottom (bottom layer), and both sides can be wired and soldered, with a layer of insulation in the middle, which is a commonly used printed circuit board. Both sides can be wired, which greatly reduces the difficulty of wiring and is therefore widely used.
The production of dual layer PCB is a little more complicated than single-sided boards for the following two main reasons.
(1) Both the top and bottom layers of the copper-lined board have to be wired.
(2) the top and bottom layers of the wire to be connected with metalized vias.
Among them, over-hole metallization is particularly critical, which is also the core process of dual layer PCB production. The so-called through-hole metallization is a layer of metal coated on the inner wall of the through-hole, in order to connect the top and bottom layers of printed wires. At present, the domestic perforation metallization mainly uses the chemical copper plating process. There are two kinds of chemical copper plating process.
① First chemically plated thin copper, then full plate plating to thicken the copper layer, and then graphic transfer.
② Chemically plating thick copper first, then directly carry out the graphic transfer.
Both of them are widely used. However, the chemical copper plating method is harmful to the environment, and it will be gradually replaced by more advanced black hole plating technology, tin/palladium direct plating technology, and polymer direct plating technology.
Printed circuit board manufacturing technology began in the mid-1940s. From the mid-1940s to the 1950s, the electronics industry was in the era of electronic tubes, and most of the printed circuit boards used were single-sided, mainly used in civilian electronic products such as radios and televisions. In the early 1960s, due to the widespread use of transistors, the size of electronic components was reduced, and the mounting density increased significantly. The 1960s saw the emergence of integrated circuits, which led to the popularization of dual layer PCB with metalized holes and the emergence of multilayer printed circuit boards and flexible printed circuit boards that could be twisted and expanded. Miniaturization, surface mount technology developed rapidly. The pins of surface-mounted devices are packaged in leadless or horizontal orientation and can be attached flat to the surface of the printed circuit board, and the pins are soldered to the printed circuit board without the need for holes.
The processing level of printed circuit boards is also improving. Currently, the level of processing is measured by the minimum width of the allowed wires, the minimum distance between the wires, the positioning accuracy of the holes, the number of layers of the PCB, etc.