To analyse the different between PCB board and integrated circuit according to the composition,characteristics and application
Composition of PCB Board
The current circuit board is mainly composed of the following:
Line and Pattern: The line is used as a tool for conducting between the originals, and a large copper surface is additionally designed as a grounding and power supply layer. The line and the patterm are made at the same time.
Dielectric: It is used to maintain the insulation between the circuit and the layers, commonly known as the substrate.
Through hole/via: The via allows the two or more layers to be electrically connected to each other, and the larger via serves as a component insert. In addition, non plating through hole(nPTH) are commonly used for surface mount positioning and are used for fixing screws during assembly.
Solder resistant/Solder Mask: Not all copper surfaces rely on tin-on parts, so areas that are not tin-stained will be printed with a layer of tin-plated material (usually epoxy) to avoid short circuits between non-tin-free lines. According to different processes, it is divided into green ink, red inkl and blue ink.
Legend/Marking/Silk screen: This is a non-essential component. Its main function is to mark the name and position frame of each part on the circuit board to facilitate post-assembly maintenance and identification.
Surface Finish: Since the copper surface is easily oxidized in the general environment, it is impossible to apply tin (poor solderability), so it will be protected on the copper surface to be tinned. The protection methods include hasling(HASL), immersion gold(ENIG), immersion silver, immersion tin, and organic solderability preservatives(OSP). These methods have their own advantages and disadvantages, collectively referred to as surface treatment.
Characteristics of PCB board
High density: For decades, the high density of printed circuit boards has grown with the increased integration of integrated circuits and advances in mounting technology.
High reliability: Through a series of inspections, tests and aging tests, the PCB can be reliably operated for a long period of time (usually 20 years).
Designability: For the performance requirements of all aspects(electrical, physical, chemical, mechanical, etc.) of PCB, the design of printed boards can be realized through standardization and standardization of design, with short time and high efficiency.
Productivity: With modern management, standardization, scale (quantity), automation and other production can be carried out to ensure product quality consistency.
Testability: Established a relatively complete test method, test standards, various test equipment and instruments to detect and identify PCB product qualification and service life.
Assemblability: PCB products are not only convenient for standardized assembly of various components, but also can be used for automatic, large-scale mass production. At the same time, PCB and various component assembly parts can be assembled to form a larger component system up to the complete machine.
Maintainability: Because PCB products and various component assembly parts are produced in a standardized design and scale, these components are also standardized. Therefore, once the system fails, it can be replaced quickly, conveniently and flexibly, and the system can be quickly restored. Of course, there are more examples, such as miniaturization, weight reduction, and high-speed signal transmission.
Integrated circuit characteristics
The integrated circuit has the advantages of small size, light weight, less lead wires and solder joints, long life, high reliability, and good performance. And low cost facilitates mass production. It is widely used not only in industrial and civil electronic equipment such as tape recorders, televisions, computers, etc., but also in military, communications, remote control, etc. The electronic equipment assembled by the integrated circuit can be increased in assembly density by several tens to several thousand times than the transistor, and the stable working time of the device can be greatly improved.
Applications of integrated circuit
555 touch timer switch: The integrated circuit IC1 is a 555 timing circuit, which is connected to a monostable circuit here. Generally, since there is no induced voltage on the P terminal of the touch panel, after the capacitor C1 is discharged through the 7.5th pin of the 555, the output of the third pin is low, the relay KS is released, and the electric light is not lit. When it is necessary to turn on the light, touch the metal piece P by hand, and the clutter signal voltage induced by the human body is added from C2 to the trigger terminal of 555, so that the output of 555 changes from low to high level, and the relay KS pulls in, the electric light will light. At the same time, the internals of pin 7 of 555 are cut off, and the power supply charges C1 through R1, which is the beginning of timing. When the voltage of the capacitor C1 rises to 2/3 of the power supply voltage, the pin 7 of 555 is turned on to discharge C1, so that the output of the third pin changes from the high level to the low level, the relay is released, the light is extinguished, and the timing ends.
Conversion between single and dual supply circuits
In the circuit of the drawing, the time base circuit 555 is connected to an unsteady circuit, and the square wave whose output frequency is 20KHz and the duty ratio is 1:1. When pin 3 is high, C4 is charged; when it is low, C3 is charged. Because of VD1 and VD2, C3 and C4 are only charged and not discharged in the circuit, the maximum charging value is EC, the B terminal is grounded, and the +/-EC dual power supply is obtained at both ends of A and C. The output current of this circuit exceeds 50mA.
The difference between PCB Board and Integrated Circuit
An integrated circuit generally refers to the integration of a chip, such as a north bridge chip on a motherboard, CPU internal, which are called an integrated circuit, and the original name is also called an integrated block. And the printed circuit board refers to the circuit board we usually see, and the solder chip is printed on the circuit board.
The integrated circuit (IC) is soldered on the PCB; the PCB version is the carrier of the IC. PCB refers to printed circuit board, it appears in almost every electronic device. If there are electronic parts in a certain device, the printed circuit boards are mounted on PCBs of various sizes. In addition to fixing various small parts, the main function of the printed circuit board is to make electrical interconnections between the various parts above.
Simply speaking, the integrated circuit integrates a general-purpose circuit onto a single chip, so it is a whole. Once it is damaged inside, the chip is damaged. While PCB can be soldered to their own components. If it it broken, it can be replaced.
