Circuit design skills PCB inqubo yokuklama

Inqubo yokwakhiwa okuyisisekelo ye-PCB imi kanjena: ukulungiselela kokuqala ->; PCB structure design -& GT; Ukuhlelwa kwe-PCB – & gt; Intambo – & gt; Ukusebenza komzila nokuphrinta kwesikrini -> Network and DRC inspections and structural inspections – > Plate making.

First: preparation. This includes preparing component libraries and schematics. “To do good work, must first sharpen its device”, to make a good board, in addition to the principle of good design, but also draw well. Before PCB design, the component library of schematic SCH and the component library of PCB should be prepared first. Peotel libraries can be used, but in general it is difficult to find a suitable library, it is best to make your own library according to the standard size information of the selected device. In principle, make PCB component library first, and then SCH component library. Izidingo zomtapo wolwazi we-PCB ziphakeme, kuthinta ngqo ukufakwa kwebhodi; Izidingo zomtapo wolwazi we-SCH zikhululekile, inqobo nje uma kukhokhelwa incazelo yezimpawu zephini nobudlelwano obuhambisana nezinto ze-PCB. PS: Note the hidden pins in the standard library. Lapho-ke umklamo ohleliwe, olungele ukwenza ukwakheka kwe-PCB.

Okwesibili: PCB design kwesakhiwo. Kulesi sinyathelo, ngokuya ngosayizi webhodi lesifunda nokuma ngomshini, indawo yebhodi le-PCB idonswa kwimvelo yokwakhiwa kwe-PCB, nezixhumi, izinkinobho / amaswishi, izimbobo zesikulufa, izimbobo zomhlangano nokunye kubekwa ngokuya ngezidingo zokubeka. And fully consider and determine the wiring area and non-wiring area (such as how much of the screw hole around the non-wiring area).

Okwesithathu: Ukuhlelwa kwe-PCB. Layout is basically putting devices on a board. At this point, if all the preparatory work mentioned above is done, the network table can be generated on the schematic diagram (Design- >; CreateNetlist), bese ungenisa itafula lenethiwekhi kumdwebo we-PCB (design-gt; Ama-LoadNets). Bona i-hubbub yedivayisi yenqwaba yonke, phakathi kwezikhonkwane nokuxhuma komugqa we-fly line. Ngemuva kwalokho ungabeka idivayisi. Ukuhlelwa okujwayelekile kwenziwa ngokwemigomo elandelayo:

(1). According to the electrical performance reasonable partition, generally divided into: digital circuit area (that is, afraid of interference, and interference), analog circuit area

(fear of interference), power drive area (interference source);

(2). Complete the same function of the circuit, should be placed as close as possible, and adjust the components to ensure the most simple connection; At the same time, adjust the relative position between the functional blocks to make the connection between the functional blocks the most concise;

(3). Installation position and installation intensity should be considered for components with large mass; Into yokushisa kufanele yehlukaniswe nento ebucayi yezinga lokushisa, futhi uma kunesidingo, kufanele kuthathwe izinyathelo zokuhambisa ngomshini ezishisayo;

(4). I/O drive device as close as possible to the edge of the printing plate, close to the outlet connector;

(5). Clock generator (such as: crystal oscillator or clock oscillator) should be as close as possible to the device using the clock;

6. In each integrated circuit between the power input pin and the ground, need to add a decoupling capacitor (generally using high frequency good monolithic capacitor); I-tantalum capacitor nayo ingabekwa izungeze izifunda eziningi ezihlanganisiwe lapho isikhala sebhodi lesifunda siqinile.

Bonke abanikazi bomhlaba. Relay coil to add discharge diode (1N4148 can be);

Namuhla. Layout requirements should be balanced, dense and orderly, not top-heavy or heavy

— Special attention should be paid to the actual size (area and height) of the components and the relative position of the components when placing the components to ensure the electrical performance of the circuit board and the feasibility and convenience of production and installation. At the same time, the above principles should be reflected

Under the premise, modify the placement of devices appropriately to make them neat and beautiful. For example, the same devices should be placed neatly and in the same direction, instead of being “strewn at random”. This step concerns the difficulty of board integral figure and next wiring degree, want to spend big effort to consider so. When layout, can make preliminary wiring first to not quite affirmative place, sufficient consideration.

Okwesine: izintambo. Ukwenza izintambo kuyinkqubo ebaluleke kakhulu ekwakhiweni kwe-PCB. Lokhu kuzothinta ngqo ukusebenza kwebhodi le-PCB. In the process of PCB design, wiring generally has such three levels of division: the first is the distribution, which is the most basic requirement of PCB design. If the line is not cloth, get everywhere is flying line, it will be a unqualified board, can say that there is no entry. The second is the satisfaction of electrical performance. Leli izinga elijwayelekile lokukala ukuthi ibhodi lesifunda eliphrintiwe liyafaneleka yini. This is after the distribution, carefully adjust the wiring, so that it can achieve the best electrical performance. Bese kuba khona ubuhle. Uma indwangu yakho yezintambo yayixhunyiwe, futhi awunayo indawo yokuthi okuthinta ukusebenza kwezinto zikagesi, kepha ubheke ngokudlulele ngokweqile, engeza okugqamile, okugqamile, okubala ukuthi ukusebenza kwakho kwezinto zikagesi kuhle kanjani, kusengudoti kwabanye iso. This brings great inconvenience to testing and maintenance. Ukuxhuma izintambo kufanele kucoceke futhi kufane, kungabi yinqwaba ngaphandle kwemithetho. Konke lokhu kufanele kufinyelelwe kumongo wokuqinisekisa ukusebenza kukagesi nokuhlangabezana nezinye izidingo zomuntu ngamunye, ngaphandle kwalokho kufanele kushiywe ingqikithi. Ukuxhuma izintambo kufanele kwenziwe ngokwemigomo elandelayo:

(1). Ngokuvamile, ikhebula lamandla nentambo yomhlabathi kufanele ihanjiswe kuqala ukuqinisekisa ukusebenza kagesi kwebhodi lesifunda. Ngokwesilinganiso leso simo esivumayo, nweba ububanzi bokuphakelwa kwamandla, ucingo lwasemhlabathini ngangokunokwenzeka, kungcono ukuthi ucingo lwasemhlabeni lubanzi kunolayini wamandla, ubudlelwano babo yile: intambo yomhlabathi> intambo yamandla> ulayini wesiginali, imvamisa ulayini wesiginali : 0.2 ~ 0.3mm, ububanzi obuncane bungafinyelela ku-0.05 ~ 0.07mm, ulayini wamandla ngu-1.2 ~ 2.5mm ngokuvamile. I-PCB yesekethe yedijithali ingasetshenziswa esifundeni esinabaqhubi bomhlaba abanzi, okungukuthi, inethiwekhi yomhlaba. (Umhlabathi we-Analog awunakusetshenziswa ngale ndlela.)

(2). In advance, wire strict requirements (such as high frequency line) for wiring, input and output side line should avoid adjacent parallel, so as not to produce reflection interference. When necessary, ground wire should be added to isolate, and the wiring of two adjacent layers should be perpendicular to each other, which is easy to produce parasitic coupling in parallel.

(3). The oscillator housing should be grounded, and the clock line should be as short as possible, and not spread all over the place. Below the clock oscillation circuit, the special high-speed logic circuit should increase the area of the ground, and should not go to other signal lines, so that the surrounding electric field tends to zero;

(4). In order to reduce the radiation of high frequency signal, 45O broken line should be used as far as possible, instead of 90O broken line. (High requirements of the line also use double arc)

(5). Any signal line should not form a loop, if unavoidable, loop should be as small as possible; Umugqa wesiginali odlula emgodini kufanele ube mncane ngangokunokwenzeka;

6. Ulayini wokhiye kufanele ube mfushane futhi ube mkhulu, ngokuvikela ezinhlangothini zombili.

Bonke abanikazi bomhlaba. When the sensitive signal and noise field signal are transmitted through flat cable, the method of “ground – signal – ground wire” is used.

Namuhla. Test points should be reserved for key signals to facilitate production and maintenance testing

Pet-name ruby. After schematic diagram wiring is completed, wiring should be optimized; At the same time, after the preliminary network check and DRC check is correct, the ground wire is filled in the area without wiring, and a large area of copper layer is used as ground wire, and the unused places are connected with the ground as ground wire on the printed board. Noma yenze ibhodi enezendlalelo eziningi, ukunikezwa kwamandla, ulayini wokubeka phansi ngamunye ungqimba.

— PCB wiring process requirements

(1). umugqa

Generally, the signal line width is 0.3mm(12mil), and the power line width is 0.77mm(30mil) or 1.27mm(50mil). Line with

The distance between lines and between lines and pads should be greater than or equal to 0.33mm(13mil). In practical application, it should be considered to increase the distance when conditions permit; When the cabling density is high, it is advisable (but not recommended) to use two cables between IC pins. The width of the cables is 0.254mm(10mil), and the distance between the cables is not less than 0.254mm(10mil).

Under special circumstances, when the pin of the device is dense and the width is narrow, the line width and line spacing can be appropriately reduced.

(2). PAD (PAD)

The basic requirements of PAD and transition hole (VIA) are: the diameter of PAD is greater than 0.6mm than the diameter of hole; For example, universal pin type resistors, capacitors and integrated circuits, using disk/hole size 1.6mm/0.8mm (63mil/32mil), socket, pin and diode 1N4007, using 1.8mm/1.0mm (71mil/39mil). In practical application, it should be determined according to the size of the actual components. If conditions are available, the size of the pad can be appropriately increased. The installation aperture of the components designed on the PCB board should be about 0.2 ~ 0.4mm larger than the actual size of the pins.

(3). Through hole (VIA)

Generally 1.27mm/0.7mm(50mil/28mil);

When the wiring density is high, the hole size can be appropriately reduced, but not too small, can consider 1.0mm/0.6mm(40mil/24mil).

(4). Spacing requirements for pads, wires and through-holes

PADandVIA: ≥0.3mm (12mil)

I-PAD ne-PAD: ≥0.3mm (12mil)

I-PADandTRACK: ≥0.3mm (12mil)

TRACKandTRACK: ≥0.3mm (12mil)

Lapho ukuminyana kuphezulu:

PADandVIA: ≥0.254mm (10mil)

I-PAD ne-PAD: ≥0.254mm (10mil)

I-PADandTRACK: ≥0.254mm (10mil)

TRACKandTRACK: ≥0.254mm (10mil)

Okwesihlanu: ukwenza kahle izintambo nokuphrinta kwesikrini. “Akukho okungcono kakhulu, okungcono kuphela”! Akunandaba noma ngabe uzikhandla kangakanani ekwakhiweni, uma usuqedile, kubheke futhi, futhi usazozwa ukuthi ungashintsha okuningi. Umthetho wokuklama ojwayelekile wesithupha ukuthi i-wiring efanele ithatha kabili ubude bokubamba izintambo kokuqala. Lapho usuzwa ukuthi akukho okudinga ukulungiswa, ungabeka ithusi. I-PolygonPlane). Ukubeka ithusi ngokuvamile kubekwa phansi ucingo (naka ukwahlukaniswa komhlaba we-analog nedijithali), ibhodi le-multilayer lingadinga nokubeka amandla. Ukuphrinta kwesikrini, kufanele sinake ukuthi singavinjelwa yidivayisi noma sisuswe yimbobo nephedi. Ngasikhathi sinye, idizayini yokubhekana nengxenye yengxenye, phansi kwegama kufanele kube ukucubungula kwesibuko, ukuze kungadidanisi ileveli.

Owesithupha: ukuhlolwa kwenethiwekhi kanye nokuhlolwa kwesakhiwo. Okokuqala, ngombono wokuthi ukwakheka okuhlelekile kulungile, amafayela enethiwekhi akhiqizwe enziwe ngamafayili kanye namafayela wenethiwekhi ahlelwe yi-NETCHECK yobudlelwano bokuxhumeka ngokomzimba, futhi idizayini ichitshiyelwa ngesikhathi ngokuya ngemiphumela yefayela lokukhipha ukuqinisekisa ukunemba kobudlelwano bezintambo zokuxhuma; Ngemuva kokuthi isheke lenethiwekhi liphasiswe kahle, isheke le-DRC lizokwenziwa ekwakhiweni kwe-PCB, futhi umklamo uzochibiyelwa ngokuya ngemiphumela yefayela lokukhipha ngesikhathi ukuqinisekisa ukusebenza kukagesi kwentambo ye-PCB. Ekugcineni, isakhiwo sokufakwa kwemishini se-PCB kufanele sihlolwe futhi siqinisekiswe.

Okwesikhombisa: ukwenza amapuleti. It is best to have a review process before doing so.

Idizayini ye-PCB isivivinyo somqondo womsebenzi, osondelene nengqondo, isipiliyoni esiphakeme, ukwakheka kwebhodi kuhle. Ngakho-ke ukwakheka kufanele kuqashelwe ngokweqile, kubhekwe ngokuphelele izici zazo zonke izici (njengokwenza lula ukugcinwa nokuhlolwa kwalokhu abantu abaningi abangakubheki), ubuhle, bazokwazi ukuklama ibhodi elihle.