We all know that making PCB board is to turn the designed schematic into a real PCB board. Please don't underestimate this process. There are many things that are feasible in principle but difficult to achieve in engineering, or others can achieve things that others can not achieve, so it is not difficult to make a PCB board. But to do a good PCB board is not an easy thing. The two major difficulties in the field of microelectronics are the processing of high-frequency signals and weak signals, in this respect PCB production level is particularly important, the same principle design, the same components, different people produced PCB will have different results, so how to make a good PCB board?
A, to clear the design objectives to accept a design task, first of all to clear its design objectives, is the ordinary PCB board high frequency PCB board small signal processing PCB board or both high frequency and small signal processing PCB board if it is an ordinary PCB board, as long as the layout and wiring is reasonable and neat, mechanical size is accurate, such as medium load line and long line, It is necessary to use certain means to deal with, reduce the load, long line to strengthen the drive, the focus is to prevent long line reflection when the board has more than 40MHz signal lines to these signal lines for special consideration such as line crosstalk and other issues if the frequency is higher on the length of the wiring there are more strict restrictions.
Two, understand the function of the components of the layout and wiring requirements We know that some special components have special requirements in the layout of the wiring such as LOTI and the analog signal amplifiers used in APH the analog signal amplifiers have requirements for the power supply to be smooth and small ripple and the analog small signal part to be as far away from the power device as possible and the small signal amplifiers on the OTI board also have special shields to shield the stray electromagnetic interference from the GL used on the NTOI board INK chip adopts ECL process, high power consumption and severe heat dissipation. Special consideration must be given to the problem of heat dissipation when layout. If natural heat dissipation is adopted, Keyou Circuit is specialized in the production of high-precision multi-layer PCB circuit boards (single panel, double panel, multi-layer board),LED aluminum substrate, copper substrate,3K full/half carbon fiber board, etc. It is a high-tech enterprise with quality assurance, timely delivery and sales as one. It is a manufacturer worthy of reliance.
Iii. Layout of components Consider the layout of components One of the first factors to consider is the electrical performance of the wire closely related components as far as possible together especially for some high-speed line layout to make it as far as possible short power signals and small signal devices to separate in the premise of meeting the circuit performance but also consider the components placed neatly beautiful and easy to test the mechanical size of the socket location also need to seriously consider the grounding in the high-speed system And interconnect latency is also one of the first things to consider in system design. Transmission time on signal lines has a significant impact on the overall system speed, especially for high speed ECL circuits. Although the IC blocks themselves are very fast, However, the system speed can be greatly reduced because of the increase of delay time caused by the delay of 2ns per 30cm line length of the common interconnect on the baseboard. Image shift register synchronization counter.
Quality control of PCB electroplating copper layer
It is very important to control the quality of electroplating copper layer of through-hole printed circuit board. Because the development of multilayer or laminated board to high density, high precision and multi-function direction, the requirements of binding force, uniform fineness, tensile strength and elongation of copper plating layer are more and more strict, and also more and more high, so the quality control of through-hole printed circuit board electroplating is particularly important.
In order to ensure the uniformity and consistency of copper plating layer of through-hole printed circuit board, in the process of copper plating of high aspect ratio printed circuit board, most of the processes are carried out under the auxiliary action of high-quality additives, with moderate air stirring and cathode movement, under the condition of relatively low current density, so that the electrode reaction control area in the hole is enlarged. The role of plating additives can be shown, coupled with the cathode movement is very conducive to the plating solution of deep plating ability to improve, increase the polarization of plating parts, electrocrystallization process of the coating nucleation rate and grain growth rate compensation each other, so as to obtain high toughness copper layer.
Of course, the current density is set according to the actual plating area of the printed circuit board being plated. From the analysis of the original understanding of electroplating, the value of current density must also depend on the main salt concentration of high acid and low copper electrolyte, solution temperature, additive content, stirring degree and other factors. In short, the technological parameters and conditions of copper plating must be strictly controlled to ensure that the thickness of the copper plating layer in the hole meets the requirements of the technical standard.