With the progress of electronic technology, the complexity of PCB (printed circuit board), ruang lingkup aplikasi memiliki perkembangan pesat. Designers engaged in HF PCB must have relevant basic theoretical knowledge and rich experience in THE manufacture of HF PCB. In other words, both schematic drawing and PCB design should be considered from the high-frequency working environment, so as to design a more ideal PCB.

Makalah ini, kabel PCB, pelat las dan menerapkan metode desain tembaga, pertama-tama, di dasar kabel PCB, kabel, kabel listrik dan persyaratan kabel tanah dalam bentuk kertas memperkenalkan desain Kabel PCB, kedua dari bantalan ikatan dan bukaan, ukuran bantalan PCB dan bentuk desain dalam desain standar, persyaratan bantalan proses pembuatan PCB diperkenalkan dengan desain solder PCB, Finally, from the PCB copper coating skills and Settings introduced the PCB copper coating design, specific follow xiaobian to understand.

Penjelasan rinci tentang metode desain kabel PCB, bantalan las dan lapisan tembaga

PCB wiring design

Pengkabelan adalah persyaratan umum desain PCB hf berdasarkan tata letak yang wajar. Cabling includes automatic cabling and manual cabling. Usually, no matter how many key signal lines there are, manual wiring should be carried out for these signal lines first. After wiring is completed, the wiring of these signal lines should be carefully checked and fixed after passing the check, and then other cables should be automatically wired. That is, the combination of manual and automatic wiring is used to complete PCB wiring.

The following aspects should be paid special attention to during the wiring of hf PCB.

1. Arah pengkabelan

The wiring of the circuit is best to adopt a full straight line according to the direction of the signal, and 45° broken line or arc curve can be used to complete the turning point, so as to reduce the external emission and mutual coupling of high-frequency signals. Pengkabelan kabel sinyal frekuensi tinggi harus sesingkat mungkin. Menurut frekuensi kerja sirkuit, panjang garis sinyal harus dipilih secara wajar, sehingga dapat mengurangi parameter distribusi dan mengurangi hilangnya sinyal. Saat membuat panel ganda, yang terbaik adalah mengarahkan dua lapisan yang berdekatan secara vertikal, diagonal atau ditekuk untuk saling berpotongan. Avoid being parallel to each other, which reduces mutual interference and parasitic coupling.

High frequency signal lines and low frequency signal lines should be separated as far as possible, and shielding measures should be taken when necessary to prevent mutual interference. Untuk penerimaan sinyal input yang relatif lemah, mudah terganggu oleh sinyal eksternal, Anda dapat menggunakan kabel arde untuk melakukan pelindung untuk mengelilinginya atau melakukan pekerjaan pelindung konektor frekuensi tinggi dengan baik. Parallel wiring should be avoided on the same level, otherwise distributed parameters will be introduced, which will affect the circuit. If unavoidable, a grounded copper foil can be introduced between the two parallel lines to form an isolation line.

In the digital circuit, for differential signal lines, should be in pairs, as far as possible to make them parallel, close to some, and the length is not much different.

2. Bentuk kabel

Dalam kabel PCB, lebar minimum kabel ditentukan oleh kekuatan adhesi antara kawat dan substrat isolator dan kekuatan arus yang mengalir melalui kawat. Ketika ketebalan foil tembaga adalah 0.05mm dan lebarnya 1mm-1.5mm, arus 2A dapat dilewatkan. Suhu tidak boleh lebih tinggi dari 3 . Kecuali untuk beberapa kabel khusus, lebar kabel lain pada lapisan yang sama harus sekonsisten mungkin. Di sirkuit frekuensi tinggi, jarak kabel akan mempengaruhi ukuran kapasitansi dan induktansi terdistribusi, dan dengan demikian mempengaruhi kehilangan sinyal, stabilitas sirkuit dan gangguan sinyal. In high speed switching circuit, wire spacing will affect signal transmission time and waveform quality. Oleh karena itu, jarak minimum perkawatan harus lebih besar dari atau sama dengan 0.5 mm. Cara terbaik adalah menggunakan garis lebar untuk kabel PCB bila memungkinkan.

There should be a certain distance between the printed wire and the edge of the PCB (no less than the thickness of the plate), which is not only easy to install and machining, but also improve the insulation performance.

When wiring can only be connected around a large circle of the line, we should use the flying line, that is, directly connected with short line to reduce the interference brought by long-distance wiring.

The circuit containing magnetic sensitive elements is sensitive to the surrounding magnetic field, while the bend of wiring of high-frequency circuit is easy to radiate electromagnetic wave. If magnetic sensitive elements are placed in PCB, it should ensure that there is a certain distance between the corner of wiring and it.

Crossover tidak diperbolehkan pada level kabel yang sama. For the line that may cross, can use “drill” with “wound” method to solve, let a certain lead namely from other resistance, capacitance, audion etc. device lead foot gap place “drill” past, or from the end of a certain lead that may cross “wound” past. In special cases where the circuit is very complex, to simplify the design, it is also allowed to solve the crossover problem with wire bonding.

Ketika sirkuit frekuensi tinggi beroperasi pada frekuensi tinggi, pencocokan impedansi dan efek antena kabel juga harus dipertimbangkan.

Because the client finally changed the previous agreement and required the interface definition and placement as defined by them, they had to change the layout to the diagram on the right. In fact, the entire PCB is only 9cm x 6cm. It is difficult to change the overall layout of the board according to the requirements of customers, so the core part of the board was not changed in the end, but the peripheral components were modified appropriately, mainly the position of the two connectors and the definition of pins were modified.

But the new layout obviously caused some trouble in the line, the original smooth line became a little messy, the length of the line increased, but also had to use a lot of holes, the difficulty of the line increased a lot.

Penjelasan rinci tentang metode desain kabel PCB, bantalan las dan lapisan tembaga

It is clear from this example that layout differences can have an impact on PCB design.

Penjelasan rinci tentang metode desain kabel PCB, bantalan las dan lapisan tembaga

3. Wiring requirements for power cables and ground cables

Tingkatkan lebar kabel daya sesuai dengan arus kerja yang berbeda. PCB Hf harus mengadopsi kabel ground area yang luas dan tata letak di tepi PCB sejauh mungkin, yang dapat mengurangi gangguan sinyal eksternal ke sirkuit; At the same time, the grounding wire of PCB can be in good contact with the shell, so that the grounding voltage of PCB is closer to the earth voltage. The grounding mode should be selected according to the actual situation. Different from the low-frequency circuit, the grounding cable of the high-frequency circuit should be nearby or multi-point grounding. The grounding cable should be short and thick to minimize the ground impedance, and the allowable current should be three times of the working current. The speaker grounding wire should be connected to the PCB power amplifier output level grounding point, do not arbitrarily grounding.

Dalam proses pengkabelan masih harus dalam waktu beberapa kunci pengkabelan yang wajar, jangan ulangi pengkabelan berkali-kali. To lock them, run the EditselectNet command to select Locked in the pre-wired properties.