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.

Eli nqaku kuqala lazisa imithetho yoyilo lobeko lwe-PCB kunye nobuchule, kwaye lichaza indlela yokuyila nokuhlola ubume be-PCB, ukusuka kwiimfuno ze-DFM yoyilo, iimfuno zoyilo lobushushu, iimfuno zomqondiso wengqibelelo, iimfuno ze-EMC, iisetingi zomaleko kunye neemfuno zokwahlulwa komhlaba amandla, kunye iimodyuli zamandla. Iimfuno kunye neminye imiba iya kucazululwa ngokweenkcukacha, kwaye ulandele umhleli ukuze ufumane iinkcukacha.

Imithetho yoyilo loyilo lwePCB

1. Kwiimeko eziqhelekileyo, onke amacandelo kufuneka acwangciswe kwindawo efanayo yebhodi yesekethe. Kuphela xa iindawo zomgangatho ophezulu zixinene kakhulu, apho ezinye izixhobo ezinobude obulinganiselweyo kunye nokuveliswa kobushushu obuphantsi, njengezixhasi ze-chip, ii-chip capacitors, kunye nee-chip capacitors, zinokufakelwa. I-Chip IC, njl. zibekwe kumaleko asezantsi.

2. Ngaphantsi kwesiseko sokuqinisekisa ukusebenza kombane, amacandelo kufuneka abekwe kwigridi kwaye acwangciswe ngokufana okanye i-perpendicular omnye komnye ukuze ahlambuluke kwaye ahle. Phantsi kweemeko eziqhelekileyo, amacandelo awavumelekanga ukuba adibane; ukucwangciswa kwamacandelo kufuneka kuhlanganiswe, kwaye amacandelo kufuneka alungelelaniswe kwi-layout yonke. Ukuhanjiswa kufana kwaye kuxinene.

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

4. Umgama ukusuka kumda webhodi yesekethe ngokuqhelekileyo ungabi ngaphantsi kwe-2MM. Ubume obungcono kakhulu bebhodi yesekethe luxande, kunye nomlinganiselo we-3: 2 okanye 4: 3. Xa ubukhulu bebhodi yesekethe bukhulu kune-200MM nge-150MM, cinga ukuba yintoni ibhodi yesekethe enokumelana namandla oMatshini.

PCB layout design skills

Kuyilo loyilo lwePCB, iiyunithi zebhodi yesekethe kufuneka zihlalutywe, kwaye uyilo loyilo kufuneka lusekelwe kumsebenzi wokuqala. Xa ubeka onke amacandelo esekethe, le migaqo ilandelayo kufuneka ifezekiswe:

1. Lungiselela indawo yecandelo lesekethe nganye esebenzayo ngokuhambelana nokuhamba kweesekethe, ukwenzela ukuba i-layout ilungele ukujikeleza kwesignali, kwaye umqondiso ugcinwe ngendlela efanayo kangangoko kunokwenzeka [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. Kwiisekethe ezisebenza kwii-frequencies eziphezulu, iiparamitha zokusabalalisa phakathi kwamacandelo kufuneka ziqwalaselwe. Kwiisekethe eziqhelekileyo, amacandelo kufuneka ahlelwe ngokuhambelana ngokusemandleni, okungeyona into enhle kuphela, kodwa kulula ukuyifaka kwaye kulula ukuyivelisa ngobuninzi.

Uyilwa njani kwaye uhlole uyilo lwePCB

1. DFM requirements for layout

1. Indlela yenkqubo efanelekileyo iye yamiselwa, kwaye zonke izixhobo zibekwe ebhodini.

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. Isikhundla sokutshintsha ukucofa, ukusetha kwakhona isixhobo, ukukhanya kwesalathisi, njl njl. kufanelekile, kwaye ibha yokubamba ayiphazamisi izixhobo ezijikelezileyo.

5. Isakhelo sangaphandle sebhodi sine-radian egudileyo ye-197mil, okanye yenzelwe ngokomzobo wesayizi wesakhiwo.

6. Iibhodi eziqhelekileyo zine-200mil process edges; amacala asekhohlo nasekunene e-backplane anemida yenkqubo engaphezulu kwe-400mil, kwaye amacala aphezulu nasezantsi anenkqubo ephela ngaphezulu kwe-680mil. Ubeko lwesixhobo alungqubani nendawo yokuvula ifestile.

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. Inowuthi yephini yesixhobo, icala lesixhobo, inowuthi yesixhobo, ithala leencwadi lesixhobo, njl.njl. eziye zalungiswa ngokuthengiswa kwamaza zithathela ingqalelo iimfuno zokubethelwa kwamaza.

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. Amalungu e-crimping angaphezulu kwe-120 mils kumgama ongaphezulu wecandelo, kwaye akukho sixhobo kwindawo yokutyhutyha kwindawo ye-welding.

11. Akukho zixhobo ezimfutshane phakathi kwezixhobo ezide, kwaye akukho zixhobo zokupakisha kunye nezixhobo ezimfutshane kunye nezincinci zokudibanisa zifakwe ngaphakathi kwe-5mm phakathi kwezixhobo ezinobude obungaphezu kwe-10mm.

12. Izixhobo zepolar zineelogo zesilika ze-polarity. Izalathiso ze-X kunye ne-Y zohlobo olufanayo lwezixhobo zeplagi ezipolarized ziyafana.

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

14. Kukho ii-3 ii-cursors zokubeka kwindawo equkethe izixhobo ze-SMD, ezibekwe kwi-“L” imilo. Umgama phakathi kombindi wekhesa yokumisa kunye nomda webhodi mkhulu kune-240 mils.

15. Ukuba ufuna ukwenza inkqubo yokukhwela ibhodi, i-layout ithathwa njengeququzelele ukuqhutyelwa kwebhodi kunye ne-PCB kunye nendibano.

16. Imiphetho echotshiweyo (i-edges engaqhelekanga) kufuneka izaliswe ngokusebenzisa i-grooves yokusila kunye nemingxuma yesitampu. Umngxuma wesitampu yi-non-metallized void, ngokubanzi i-40 mls ububanzi kunye ne-16 mils ukusuka emphethweni.

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

Okwesibini, iimfuno zoyilo lwe-thermal yoyilo

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. Uyilo luthathela ingqalelo iitshaneli ezifanelekileyo kunye nezigudileyo zokuphelisa ubushushu.

4. I-electrolytic capacitor kufuneka ihlulwe ngokufanelekileyo kwisixhobo sokushisa okuphezulu.

5. Cinga ukutshatyalaliswa kobushushu bezixhobo eziphezulu zamandla kunye nezixhobo phantsi kwe-gusset.

Okwesithathu, iimfuno zemfezeko yomqondiso woyilo

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. Isantya esiphezulu kunye nesantya esiphantsi, idijithali kunye ne-analog zicwangciswe ngokwahlukileyo ngokweemodyuli.

5. Ukumisela i-topological structure yebhasi esekelwe kuhlalutyo kunye neziphumo zokulinganisa okanye amava akhoyo ukuze kuqinisekiswe ukuba iimfuno zenkqubo ziyafezekiswa.

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.

Isine, iimfuno ze-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. Ukuze uthintele ukuphazamiseka kwe-electromagnetic phakathi kwesixhobo esikumphezulu we-welding webhodi enye kunye nebhodi enye emeleneyo, akukho zixhobo ezinovakalelo kunye nezixhobo ezinamandla zemitha kufuneka zibekwe kumphezulu we-welding webhodi enye.

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. Isekethe yokukhusela ibekwe kufuphi ne-interface yesiphaluka, ngokulandela umgaqo wokukhusela kuqala kwaye emva koko ukucoca.

5. Umgama osuka kumzimba okhuselayo kunye negobolondo elikhuselayo ukuya kumzimba okhuselayo kunye negobolondo lekhava elikhuselayo lingaphezulu kwe-500 mils yezixhobo ezinamandla okuhambisa okanye ngokukodwa ubuthathaka (njenge-crystal oscillators, iikristale, njl.).

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. Xa iileya ezimbini zesignali zihambelana ngokuthe ngqo komnye nomnye, imigaqo yocingo echanekileyo kufuneka ichazwe.

2. Uluhlu lwamandla oluphambili lukufuphi nomgangatho walo ohambelana nomhlaba kangangoko kunokwenzeka, kwaye umbane wamandla udibana nomgaqo we-20H.

3. Each wiring layer has a complete reference plane.

4. Iibhodi ze-Multi-layer zi-laminated kunye ne-core material (CORE) i-symmetrical ukuthintela ukulwa okubangelwa ukusabalalisa okungalinganiyo koxinano lwesikhumba sobhedu kunye nobukhulu be-asymmetrical medium.

5. Ubukhulu bebhodi akufanele budlule i-4.5mm. Kulabo abanobukhulu obungaphezulu kwe-2.5mm (i-backplane enkulu kune-3mm), amagcisa kufuneka aqinisekise ukuba akukho ngxaki nge-PCB processing, indibano, kunye nezixhobo, kwaye ubukhulu bebhodi yekhadi le-PC yi-1.6mm.

6. Xa umlinganiselo wokutyeba ukuya kububanzi be-via mkhulu kuno-10:1, uya kuqinisekiswa ngumvelisi we-PCB.

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

8. Amandla kunye nokulungiswa komhlaba kwamacandelo abalulekileyo ahlangabezana neemfuno.

9. Xa ulawulo lwe-impedance lufunekayo, iiparamitha zokumisela umaleko zihlangabezana neemfuno.

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. Xa ibhodi enye inika amandla kwi-subboard, beka isiphaluka esihambelanayo sokucoca kufuphi ne-outlet yamandla yebhodi enye kunye ne-inlet yamandla ye-subboard.

Zisixhenxe, ezinye iimfuno

1. Uyilo luthathela ingqalelo ukuguquguquka okupheleleyo kwe-wiring, kwaye ukuhamba kwedatha okuphambili kunengqiqo.

2. Lungisa izabelo zepin yokukhutshelwa ngaphandle, iFPGA, EPLD, umqhubi webhasi kunye nezinye izixhobo ngokweziphumo zoyilo ukuze kunyuswe ubeko.

3. Uyilo luthathela ingqalelo ukunyuka okufanelekileyo kwendawo kwi-wiring exineneyo ukuphepha imeko engenakuhamba ngayo.

4. Ukuba izinto ezikhethekileyo, izixhobo ezikhethekileyo (ezifana ne-0.5mmBGA, njl.njl.), kunye neenkqubo ezizodwa zamkelwa, ixesha lonikezelo kunye nokuqhubekeka kuqwalaselwe ngokupheleleyo, kwaye kungqinwe ngabavelisi bePCB kunye nabasebenzi benkqubo.

5. I-pin ehambelanayo yobudlelwane be-gusset connector iqinisekisiwe ukukhusela isalathiso kunye nokuqhelaniswa kwekhonkco ye-gusset ukuba iguqulwe.

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. Emva kokugqitywa koyilo, umzobo wendibano oyi-1:1 unikezelwe kubasebenzi beprojekthi ukujonga ukuba ngaba ukhetho lwephakheji yesixhobo luchanekile kusini na kwindawo yesixhobo.

9. Ekuvuleni kwefestile, indiza yangaphakathi ithathwa njengento ehlehlisiwe, kwaye indawo efanelekileyo yokuthintela i-wiring ibekwe.