Circuit design skills PCB kapangidwe kake

Njira yayikulu yopangira PCB ndi iyi: kukonzekera koyambirira ->; PCB structure design -& GT; Makhalidwe a PCB – & gt; Kulumikizana – & gt; Kukhathamiritsa ndi kusindikiza pazenera -> 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. Zofunikira pa laibulale ya PCB ndizokwera, zimakhudza kukhazikitsa kwa board; SCH’s component library requirements are relatively loose, as long as attention is paid to the definition of pin attributes and the corresponding relationship with PCB components. PS: Note the hidden pins in the standard library. Ndiye kapangidwe koyeserera, kokonzeka kupanga kapangidwe ka PCB.

Chachiwiri: Mapangidwe a PCB. Mu gawo ili, malinga ndi kukula kwa bolodi la dera ndi mawonekedwe amakanema, PCB board pamwamba imakopeka ndi kapangidwe ka PCB, ndi zolumikizira, mabatani / ma swichi, mabowo opangira, mabowo amisonkhano ndi zina zotero zimayikidwa malingana ndi malo omwe mukufuna. 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).

Chachitatu: Makhalidwe a 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), ndiyeno tumizani tebulo lapa netiweki pazithunzi za PCB (design-gt; Zambiri Zamtundu) Onani chipwirikiti cha mulu wonsewo, pakati pa zikhomo ndi kulumikizana kwa mzere wouluka. Mutha kuyala chipangizocho. Kapangidwe kake kamachitika malinga ndi mfundo izi:

(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; Chowotcha chiyenera kupatulidwa kuchokera kuzinthu zotentha, ndipo ngati kuli kotheka, njira zotumizira zotentha ziyenera kuganiziridwa;

(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); Tantalum capacitor itha kuyikidwanso mozungulira ma circuits angapo ophatikizika pomwe bolodi la dera ndi lolimba.

Eni malo onse. Relay coil to add discharge diode (1N4148 can be);

Lero. 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.

Chachinayi: kulumikiza. Kulumikizana ndi njira yofunikira kwambiri pakupanga kwa PCB. Izi zidzakhudza mwachindunji magwiridwe antchito a PCB board. 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. Uwu ndiye muyezo woyesa ngati bolodi losindikizidwa lili loyenerera. This is after the distribution, carefully adjust the wiring, so that it can achieve the best electrical performance. Ndiye pali zokongoletsa. If your wiring cloth was connected, also do not have the place that what affects electric appliance performance, but look past desultorily, add colourful, brightly colored, that calculates how your electric appliance performance is good, still be rubbish in others eye. This brings great inconvenience to testing and maintenance. Kulumikizana kuyenera kukhala koyenera komanso yunifolomu, osadutsa popanda malamulo. All these should be achieved in the context of ensuring electrical performance and meeting other individual requirements, otherwise it is to abandon the essence. Kulumikizana kuyenera kuchitidwa molingana ndi mfundo izi:

(1). Mwambiri, chingwe chamagetsi ndi chingwe pansi chimayenera kuyendetsedwa kaye kuti zitsimikizire magwiridwe antchito a bolodi. Potengera momwe mkhalidwewo ungalolere, kukulitsa mphamvu zamagetsi, waya wapadziko lonse momwe zingathere, ndibwino kuti waya wapansi azikhala wokulirapo kuposa mzere wamagetsi, ubale wawo ndi: waya wapansi> chingwe champhamvu> mzere wazizindikiro, nthawi zambiri mzere wazizindikiro ndi : 0.2 ~ 0.3mm, m’lifupi woonda angafikire 0.05 ~ 0.07mm, mphamvu mzere ndi 1.2 ~ 2.5mm ambiri. PCB yoyendetsa digito itha kugwiritsidwa ntchito poyenda ndi oyendetsa pansi, ndiye kuti netiweki yapansi. (Malo a Analogi sangathe kugwiritsidwa ntchito motere.)

(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; Chizindikiro chopyola mu bowo chizikhala chocheperako;

6. The key line should be short and thick, with protection on both sides.

Eni malo onse. When the sensitive signal and noise field signal are transmitted through flat cable, the method of “ground – signal – ground wire” is used.

Lero. 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. Or make it multi-layer board, power supply, grounding line each occupy a layer.

— PCB wiring process requirements

(1). mzere

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)

PADandPAD: ≥0.3mm (12mil)

PADandTRACK: ≥0.3mm (12mil)

TRACKandTRACK: ≥0.3mm (12mil)

Pamene kachulukidwe kali:

PADandVIA: ≥0.254mm (10mil)

PADandPAD: ≥0.254mm (10mil)

PADandTRACK: ≥0.254mm (10mil)

TRACKandTRACK: ≥0.254mm (10mil)

Chachisanu: kukhathamiritsa kwa zingwe ndi kusindikiza pazenera. “Palibe chabwino, koma chabwino”! Ngakhale mutachita khama bwanji pakupanga, mukamaliza, yang’aninso, ndipo mukumvabe kuti mutha kusintha zambiri. Malingaliro apadera a chala chachikulu ndikuti kulumikizana koyenera kumatenga kawiri bola kutalika kwa waya woyamba. Mukawona kuti palibe chomwe chikufunika kukonza, mutha Kuyika mkuwa. PolygonPlane). Kuyika mkuwa nthawi zambiri kuyika waya wapansi (samalani kupatukana kwa analog ndi digito), bolodi yama multilayer ingafunikenso kuyika mphamvu. For screen printing, we should pay attention to not be blocked by the device or removed by the hole and pad. Nthawi yomweyo, mapangidwe oyang’anizana ndi mawonekedwe am’munsi, pansi pamawu akuyenera kukhala kukonza kwagalasi, kuti asasokoneze mulingo.

Chachisanu ndi chimodzi: maukonde ndi kuwunika kwa DRC ndikuwunika mawonekedwe. Choyamba, poganiza kuti mapangidwe ake ndi olondola, mafayilo amtundu wa PCB ndi mafayilo amachitidwe amtunduwu ndi NETCHECK yolumikizana, ndipo mapangidwe ake amasinthidwa munthawi yake malinga ndi zotsatira za mafayilo kuti awonetsetse kulumikizana kwa kulumikizana kwa zingwe; Pambuyo cheke maukonde wadutsa moyenera, cheke cha DRC chidzachitike pamapangidwe a PCB, ndipo mapangidwewo adzasinthidwa malinga ndi zotsatira za fayilo mu nthawi kuti zitsimikizire magwiridwe antchito amagetsi a PCB. Pomaliza, makina okhazikitsa mawonekedwe a PCB ayenera kuwunikiridwa ndikutsimikiziridwa.

Chachisanu ndi chiwiri: kupanga mbale. It is best to have a review process before doing so.

Kupanga kwa PCB ndi kuyesa kwa ntchitoyo, yemwe ali pafupi ndi malingaliro, luso lapamwamba, kapangidwe ka bolodi ndiwabwino. Chifukwa chake mapangidwe ake ayenera kukhala osamala kwambiri, kulingalira mokwanira pazinthu zonse (monga kuthandizira kukonza ndikuwunika anthu ambiri samawaganizira), kuchita bwino, kudzatha kupanga bolodi labwino.