Circuit design skills पीसीबी design process

General PCB basic design process is as follows: preliminary preparation – >; PCB structure design -& GT; पीसीबी लेआउट – & gt; तारि – – & gt; मार्ग अनुकूलन र स्क्रीन प्रिन्टि – -> 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. सिद्धान्त मा, पीसीबी घटक पुस्तकालय पहिलो, र त्यसपछि SCH घटक पुस्तकालय बनाउन। पीसीबी घटक पुस्तकालय आवश्यकताहरु उच्च छन्, यो सीधा बोर्ड स्थापना लाई प्रभावित गर्दछ; 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. तब योजनाबद्ध डिजाइन, पीसीबी डिजाइन गर्न को लागी तयार छ।

दोस्रो: पीसीबी संरचनात्मक डिजाइन। यस चरण मा, सर्किट बोर्ड आकार र मेकानिकल स्थिति अनुसार, पीसीबी बोर्ड सतह पीसीबी डिजाइन वातावरण मा तैयार छ, र कनेक्टर, बटन/स्विच, पेंच छेद, विधानसभा छेद र यति मा स्थिति आवश्यकताहरु अनुसार राखिएको छ। 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).

तेस्रो: पीसीबी लेआउट। 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), र त्यसपछि पीसीबी आरेख मा नेटवर्क तालिका आयात (डिजाइन- gt; लोडनेट)। पिन र फ्लाई लाइन शीघ्र जडान को बीच, पूरा ढेर को उपकरण हबब हेर्नुहोस्। तपाइँ त्यसपछि उपकरण बाहिर राख्न सक्नुहुन्छ। सामान्य लेआउट निम्न सिद्धान्तहरु अनुसार गरिन्छ:

(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; हीटिंग तत्व तापमान संवेदनशील तत्व बाट अलग हुनुपर्छ, र यदि आवश्यक हो, थर्मल संवहन उपायहरु लाई विचार गरिनु पर्छ;

(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); एक tantalum संधारित्र पनि धेरै एकीकृत सर्किट वरिपरि राख्न सकिन्छ जब सर्किट बोर्ड ठाउँ तंग छ।

सबै जग्गा मालिकहरु। Relay coil to add discharge diode (1N4148 can be);

आज। 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.

चौथो: तार। तारि PC पीसीबी डिजाइन मा सबैभन्दा महत्त्वपूर्ण प्रक्रिया हो। यो सीधा पीसीबी बोर्ड को प्रदर्शन लाई प्रभावित गर्दछ। पीसीबी डिजाइन को प्रक्रिया मा, तारि generally सामान्यतया विभाजन को यस्तो तीन स्तर छ: पहिलो वितरण छ, जो पीसीबी डिजाइन को सबैभन्दा आधारभूत आवश्यकता हो। 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. यो मापन को लागी मानक छ कि एक मुद्रित सर्किट बोर्ड योग्य छ। This is after the distribution, carefully adjust the wiring, so that it can achieve the best electrical performance. त्यसपछि त्यहाँ सौंदर्यशास्त्र छ। 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. तारि ne सफा र वर्दी हुनुपर्छ, नियम बिना crisscross छैन। All these should be achieved in the context of ensuring electrical performance and meeting other individual requirements, otherwise it is to abandon the essence. तारि the निम्न सिद्धान्तहरु अनुसार गरिनु पर्छ:

(1)। सामान्य मा, बिजुली केबल र जमीन केबल सर्किट बोर्ड को विद्युत प्रदर्शन सुनिश्चित गर्न को लागी पहिले मार्गनिर्देशित गर्नु पर्छ। दायरा मा शर्त छ कि अनुमति दिन्छ, बिजुली आपूर्ति को चौडाई फराकिलो, जमीन तार जहाँ सम्म सम्भव छ, यो सबै भन्दा राम्रो छ कि जमीन तार बिजुली लाइन भन्दा फराकिलो छ, तिनीहरुको सम्बन्ध हो: जमीन तार> पावर लाइन> सिग्नल लाइन, सामान्यतया संकेत लाइन चौडाइ हो : ०.२ ~ ०.३mm, पातलो चौडाई ०.०५ ~ ०.०mmmm सम्म पुग्न सक्छ, पावर लाइन १.२ ~ २.५mm सामान्यतया छ। The PCB of a digital circuit can be used in a circuit with wide ground conductors, that is, a ground network. (Analog ground cannot be used in this way.)

(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; छेद को माध्यम बाट सिग्नल लाइन सकेसम्म सानो हुनुपर्छ;

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

सबै जग्गा मालिकहरु। When the sensitive signal and noise field signal are transmitted through flat cable, the method of “ground – signal – ground wire” is used.

आज। 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)। लाइन

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

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)

जब घनत्व उच्च छ:

PADandVIA: ≥0.254mm (10mil)

PADandPAD: ≥0.254mm (10mil)

PADandTRACK: ≥0.254mm (10mil)

TRACKandTRACK: ≥0.254mm (10mil)

पाँचौं: तार अनुकूलन र स्क्रीन प्रिन्टि। “त्यहाँ कुनै उत्तम छैन, मात्र राम्रो”! कुनै फरक पर्दैन कती मेहनत तपाइँ डिजाइन मा राख्नुभएको छ, जब तपाइँ गर्नुभयो, यसलाई फेरि हेर्नुहोस्, र तपाइँ अझै पनी महसुस गर्नुहुन्छ कि तपाइँ धेरै परिवर्तन गर्न सक्नुहुन्छ। औंठा को एक सामान्य डिजाइन नियम हो कि इष्टतम तारि twice दुई पटक लामो प्रारम्भिक तारिख को रूप मा लामो समय लाग्छ। एक पटक तपाइँलाई लाग्छ कि केहि फिक्सिंग को आवश्यकता छैन, तपाइँ तामा राख्न सक्नुहुन्छ। बहुभुज विमान)। तांबे सामान्यतया जमीन तार बिछ्याउने (एनालग र डिजिटल जमीन को अलग गर्न ध्यान दिनुहोस्), multilayer बोर्ड पनि बिजुली बिछ्याउन आवश्यक हुन सक्छ। For screen printing, we should pay attention to not be blocked by the device or removed by the hole and pad. एकै समयमा, घटक सतह को सामना गर्न को लागी डिजाइन, शब्द को तल दर्पण प्रशोधन हुनु पर्छ, ताकि स्तर को भ्रमित गर्न को लागी।

छैटौं: नेटवर्क र DRC जाँच र संरचना जाँच। सर्वप्रथम, आधार मा कि योजनाबद्ध डिजाइन सही छ, उत्पन्न पीसीबी नेटवर्क फाइलहरु र योजनाबद्ध नेटवर्क फाइलहरु शारीरिक सम्बन्ध सम्बन्ध को लागी NETCHECK हो, र डिजाइन समय मा आउटपुट फाइल परिणाम अनुसार तारि connection जडान सम्बन्ध को शुद्धता सुनिश्चित गर्न को लागी संशोधन गरीन्छ; नेटवर्क जाँच सही तरिकाले पारित गरेपछि, DRC जाँच पीसीबी डिजाइन मा बाहिर गरिनेछ, र डिजाइन समय मा आउटपुट फाइल परिणाम अनुसार पीसीबी तारि of को विद्युत प्रदर्शन सुनिश्चित गर्न को लागी संशोधन गरिनेछ। अन्तमा, पीसीबी को मेकानिकल स्थापना संरचना थप जाँच गरीयो र पुष्टि गर्नुपर्छ।

सातौं: प्लेट बनाउने। It is best to have a review process before doing so.

पीसीबी डिजाइन काम को मन को एक परीक्षण हो, जो मन, उच्च अनुभव को नजिक छ, बोर्ड को डिजाइन राम्रो छ। तेसैले डिजाइन अत्यन्त सावधान हुनु पर्छ, पुरा तरिकाले सबै पक्षहरु को कारकहरु लाई विचार गर्नुहोस् (जस्तै रखरखाव को सुविधा को रूप मा र यो धेरै मानिसहरु लाई विचार गर्दैन को निरीक्षण), उत्कृष्टता, एक राम्रो बोर्ड डिजाइन गर्न सक्षम हुनेछ।