In design, layout is an important part. The quality of the layout result will directly affect the effect of the wiring, so it can be considered that a reasonable layout is the first step to a successful PCB design. Especially the pre-layout is the process of thinking about the entire circuit board, signal flow, heat dissipation, structure and other structures. If the pre-layout fails, no amount of effort will be needed.

PCB layout design The design process flow of printed circuit boards includes schematic design, electronic component database registration, design preparation, block division, electronic component configuration, configuration confirmation, wiring and final inspection. In the process of the process, no matter which process is found to be a problem, it must be returned to the previous process for reconfirmation or correction.

Artikel iki pisanan pirso aturan lan Techniques desain tata PCB, lan banjur nerangake carane ngrancang lan mriksa tata letak PCB, saka syarat DFM tata letak kang, syarat desain termal, syarat integritas sinyal, syarat EMC, setelan lapisan lan syarat divisi lemah daya, lan modul daya. Syarat lan aspek liyane bakal dianalisis kanthi rinci, lan tindakake editor kanggo ngerteni rincian kasebut.

Aturan desain tata letak PCB

1. Ing kahanan normal, kabeh komponen kudu disusun ing lumahing padha Papan sirkuit. Mung nalika komponen ndhuwur-tingkat banget kandhel, sawetara piranti karo dhuwur winates lan generasi panas kurang, kayata resistor chip, kapasitor chip, lan kapasitor chip, bisa diinstal. Chip IC, etc diselehake ing lapisan ngisor.

2. Ing premis kanggo mesthekake kinerja electrical, komponen kudu diselehake ing kothak lan disusun podo karo utawa jejeg kanggo saben liyane supaya rapi lan ayu. Ing kahanan normal, komponen ora diijini tumpang tindih; susunan komponen kudu kompak, lan komponen kudu disusun ing kabeh tata letak. Distribusi kasebut seragam lan padhet.

3. The minimum distance between adjacent land patterns of different components on the circuit board should be above 1mm.

4. Jarak saka pinggir papan sirkuit umume ora kurang saka 2MM. Bentuk papan sirkuit sing paling apik yaiku persegi dowo, lan rasio aspek yaiku 3: 2 utawa 4: 3. Nalika ukuran papan sirkuit luwih gedhe saka 200MM dening 150MM, nimbang apa papan sirkuit bisa tahan kekuatan Mechanical.

PCB layout design skills

Ing desain tata letak PCB, unit papan sirkuit kudu dianalisis, lan desain tata letak kudu adhedhasar fungsi wiwitan. Nalika laying metu kabeh komponen saka sirkuit, prinsip ing ngisor iki kudu ketemu:

1. Atur posisi saben unit sirkuit fungsional miturut aliran sirkuit, supaya tata letak trep kanggo sirkulasi sinyal, lan sinyal tetep ing arah sing padha sabisa [1].

2. Take the core components of each functional unit as the center and lay out around him. The components should be uniformly, integrally and compactly arranged on the PCB to minimize and shorten the leads and connections between the components.

3. Kanggo sirkuit operasi ing frekuensi dhuwur, paramèter distribusi antarane komponen kudu dianggep. Ing sirkuit umum, komponen kudu disusun ing podo karo sabisa, kang ora mung ayu, nanging uga gampang kanggo nginstal lan gampang kanggo gawé massa.

Cara ngrancang lan mriksa tata letak PCB

1. DFM requirements for layout

1. Rute proses optimal wis ditemtokake, lan kabeh piranti wis diselehake ing Papan.

2. The origin of the coordinates is the intersection of the left and lower extension lines of the board frame, or the lower left pad of the lower left socket.

3. The actual size of the PCB, the location of the positioning device, etc. are consistent with the process structure element map, and the device layout of the area with restricted device height requirements meets the requirements of the structure element map.

4. Posisi switch dial, piranti ngreset, lampu indikator, lan sapiturute cocok, lan gagang ora ngganggu piranti ing saubengé.

5. Pigura njaba Papan wis radian Gamelan saka 197mil, utawa dirancang miturut drawing ukuran struktural.

6. Papan biasa duwe pinggiran proses 200mil; sisih kiwa lan tengen backplane duwe sudhut proses luwih saka 400mil, lan sisih ndhuwur lan ngisor duwe sudhut proses luwih saka 680mil. Panggonan seko piranti ora konflik karo posisi mbukak jendhela.

7. All kinds of additional holes (ICT positioning hole 125mil, handle bar hole, elliptical hole and fiber holder hole) that need to be added are all missing and set correctly.

8. Piranti pin Jarak, arah piranti, Jarak piranti, perpustakaan piranti, lan sapiturute sing wis diproses dening gelombang soldering njupuk menyang akun syarat gelombang soldering.

9. The device layout spacing meets the assembly requirements: surface mount devices are greater than 20mil, IC is greater than 80mil, and BGA is greater than 200mil.

10. Ing bagean crimping duwe luwih saka 120 mils ing kadohan lumahing komponèn, lan ora ana piranti ing area liwat saka bagean crimping ing lumahing welding.

11. Ora ana piranti cendhak antarane piranti dhuwur, lan ora piranti tembelan lan piranti interposing cendhak lan cilik diselehake ing 5mm antarane piranti karo dhuwur luwih saka 10mm.

12. Piranti polar duwe logo silkscreen polaritas. Pandhuan X lan Y saka jinis komponen plug-in polarisasi sing padha padha.

13. All devices are clearly marked, no P*, REF, etc. are not clearly marked.

14. Ana 3 posisi kursor ing lumahing ngemot piranti SMD, kang diselehake ing wangun “L”. Jarak antarane tengah kursor posisi lan pinggiran Papan luwih saka 240 mil.

15. Yen sampeyan kudu nindakake proses asrama, tata letak dianggep nggampangake proses boarding lan PCB lan perakitan.

16. Pinggir-pinggiran sing dicemplungake (pinggiran ora normal) kudu diisi kanthi alur panggilingan lan bolongan cap. Bolongan prangko minangka kekosongan non-metal, umume diameter 40 mil lan 16 mil saka pinggir.

17. The test points used for debugging have been added in the schematic diagram, and they are placed appropriately in the layout.

Kapindho, syarat desain termal saka tata letak

1. Heating components and exposed components of the casing are not in close proximity to wires and heat-sensitive components, and other components should also be properly kept away.

2. The placement of the radiator takes into account the convection problem, and there is no interference of high components in the projection area of ​​the radiator, and the range is marked on the mounting surface with silk screen.

3. Tata letak njupuk menyang akun saluran boros panas cukup lan Gamelan.

4. Kapasitor elektrolitik kudu dipisahake kanthi bener saka piranti panas dhuwur.

5. Coba boros panas piranti lan piranti daya dhuwur ing sangisore gusset.

Katelu, syarat integritas sinyal saka tata letak

1. The start-end matching is close to the sending device, and the end matching is close to the receiving device.

2. Place decoupling capacitors close to related devices

3. Place crystals, crystal oscillators and clock drive chips close to related devices.

4. Kacepetan dhuwur lan kacepetan kurang, digital lan analog disusun kanthi kapisah miturut modul.

5. Nemtokake struktur topologi bis adhedhasar asil analisis lan simulasi utawa pengalaman sing wis ana kanggo mesthekake yen syarat sistem wis ketemu.

6. If it is to modify the board design, simulate the signal integrity problem reflected in the test report and give a solution.

7. The layout of the synchronous clock bus system meets the timing requirements.

Papat, syarat EMC

1. Inductive devices that are prone to magnetic field coupling, such as inductors, relays, and transformers, should not be placed close to each other. When there are multiple inductance coils, the direction is vertical and they are not coupled.

2. Supaya gangguan elektromagnetik antarane piranti ing lumahing welding saka Papan siji lan Papan siji jejer, ora piranti sensitif lan piranti radiation kuwat kudu diselehake ing lumahing welding saka Papan siji.

3. The interface components are placed close to the edge of the board, and appropriate EMC protection measures have been taken (such as shielding shells, hollowing out of the power supply ground, etc.) to improve the EMC capability of the design.

4. Sirkuit proteksi diselehake ing cedhak sirkuit antarmuka, miturut prinsip perlindungan pisanan lan banjur nyaring.

5. Jarak saka awak shielding lan Nihan shielding kanggo awak shielding lan shielding tutup Nihan luwih saka 500 mils kanggo piranti karo daya ngirim dhuwur utawa utamané sensitif (kayata osilator kristal, kristal, etc.).

6. A 0.1uF capacitor is placed near the reset line of the reset switch to keep the reset device and reset signal away from other strong devices and signals.

Five, layer setting and power supply and ground division requirements

1. Nalika loro lapisan sinyal langsung jejer kanggo saben liyane, aturan wiring vertikal kudu ditetepake.

2. Lapisan daya utama jejer kanggo lapisan lemah sing cocog sabisa, lan lapisan daya meets aturan 20H.

3. Each wiring layer has a complete reference plane.

4. Papan multi-lapisan laminated lan materi inti (CORE) simetris kanggo nyegah warping disebabake distribusi ora rata saka Kapadhetan kulit tembaga lan kekandelan asimetris saka medium.

5. Ing kekandelan saka Papan ngirim ora ngluwihi 4.5mm. Kanggo sing duwe kekandelan luwih saka 2.5mm (backplane luwih saka 3mm), teknisi kudu wis dikonfirmasi sing ora ana masalah karo Processing PCB, Déwan, lan peralatan, lan kekandelan Papan kertu PC 1.6mm.

6. Nalika rasio kekandelan-kanggo-diameteripun liwat luwih saka 10:1, iku bakal dikonfirmasi dening Produsèn PCB.

7. The power and ground of the optical module are separated from other power and ground to reduce interference.

8. Daya lan pangolahan lemah komponen kunci nyukupi syarat.

9. Nalika kontrol impedansi dibutuhake, paramèter setelan lapisan ketemu syarat.

Six, power module requirements

1. The layout of the power supply part ensures that the input and output lines are smooth and do not cross.

2. Nalika Papan siji Penyetor daya kanggo subboard, nyeleh sirkuit Filter cocog cedhak stopkontak saka Papan siji lan welingan daya saka subboard.

Seven, other requirements

1. Tata letak njupuk menyang akun Gamelan sakabèhé saka wiring, lan aliran data utama cukup.

2. Nyetel assignments pin saka pangecualian, FPGA, EPLD, driver bis lan piranti liyane miturut asil tata kanggo ngoptimalake tata.

3. Tata letak njupuk menyang akun Tambah cocok saka papan ing wiring kandhel supaya kahanan sing ora bisa routed.

4. Yen bahan khusus, piranti khusus (kayata 0.5mmBGA, etc.), lan pangolahan khusus sing diadopsi, wektu pangiriman lan processability wis kebak dianggep, lan dikonfirmasi dening manufaktur PCB lan personel proses.

5. Pin cocog hubungan konektor gusset wis dikonfirmasi kanggo nyegah arah lan orientasi saka konektor gusset saka kuwalik.

6. If there are ICT test requirements, consider the feasibility of adding ICT test points during layout, so as to avoid difficulty in adding test points during the wiring phase.

7. When a high-speed optical module is included, the layout of the optical port transceiver circuit is prioritized.

8. Sawise tata letak wis rampung, drawing Déwan 1: 1 wis kasedhiya kanggo personel project kanggo mriksa apa pilihan paket piranti bener marang entitas piranti.

9. Ing bukaan saka jendhela, bidang njero wis dianggep retracted, lan wilayah larangan wiring cocok wis disetel.