Selecting PCB core thickness becomes an issue when a guddiga wareegsan oo daabacan (PCB) soo -saaraha wuxuu helaa xigasho uu ku codsanayo naqshadeyn dhinacyo badan leh iyo shuruudaha agabku ma dhammaystirna ama lama sheegin haba yaraatee. Mararka qaarkood tani waxay dhacdaa sababtoo ah isku -darka agabka PCB ee la isticmaalay muhiim uma aha waxqabadka; If the overall thickness requirement is met, the end user may not care about the thickness or type of each layer.

But at other times, performance is more important and the thickness needs to be tightly controlled for optimal performance. If the PCB designer clearly communicates all requirements in the documentation, then the manufacturer will know what the requirements are and will set the materials accordingly.

Arrimaha naqshadeeyayaasha PCB waxay u baahan yihiin inay tixgeliyaan

Waxay ka caawisaa naqshadeeyayaasha inay fahmaan agabka la heli karo oo inta badan la isticmaalo, si ay u isticmaali karaan xeerarka naqshadeynta habboon si ay PCBS ugu dhisaan si degdeg ah oo sax ah. Waxa soo socdaa waa sharraxaad kooban oo ku saabsan noocyada soo -saareyaasha alaabta ay doorbidaan inay adeegsadaan, iyo waxa laga yaabo inay u baahdaan si ay shaqada ugu beddelaan si dhakhso ah iyadoon dib loo dhigin mashruucaaga.

Fahmaan qiimaha dahaarka PCB iyo alaabada

Waxaa muhiim ah in la fahmo in alaabta laminate -ka PCB la iibiyo oo ay ku shaqeeyaan “nidaam” iyo in maaddada asaasiga ah iyo sii -diyaarsiga uu sii -hayaha soo -saaraha si degdeg ah u isticmaalo ay inta badan ka soo jeedaan isla nidaamkii. In other words, the constituent elements are all parts of a particular product, but with some variations, such as thickness, copper weight and prepreg style. Ka sokow ogaanshaha iyo ku -celcelinta, waxaa jira sababo kale oo loo kaydin karo tiro kooban oo ah noocyada laminate -ka.

Prepreg and inner core systems are formulated to work together, but may not work correctly when used in combination with other products. For example, the Isola 370HR core material will not be used in the same stack as the Nelco 4000-13 prepreg. It’s possible they’ll work together in some situations, but more likely they won’t. Nidaamyada isku -dhafan ayaa ku geeya dhul aan la garanayn, halkaas oo dabeecadda agabka (oo si fiican loo yaqaan marka loo isticmaalo nidaamyo isku mid ah) aan dib dambe loo qaadan karin. Careless or unwitting mixing and matching of material types can lead to serious failures, so no manufacturer will mix and match unless the type is proven to be suitable for “mixed” stacking.

Sabab kale oo loo haysto alaab alaab cidhiidhi ah ayaa ah qiimaha sare ee shahaadaynta UL, sidaa darteed waxay ku badan tahay warshadaha PCB in la xaddido tirada shahaadooyinka xulasho yar oo agab ah. Manufacturers will often agree to make products on laminate without standard stock, but be aware that they cannot provide UL certification through QC documentation. Kani waa xulasho wanaagsan oo loogu talagalay naqshadaha aan UL ahayn haddii la shaaciyo oo hore loogu heshiiyo oo soo-saaruhu uu yaqaan shuruudaha ka-shaqaynta nidaamka dahaarka ee su’aasha ah. For UL work, it is best to find out the manufacturer inventory of your choice and design boards to match it.

Ipc-4101d and foil construction

Now that these facts are out in the open, there are two other things to know before jumping into design. First, it is best to specify laminates according to industry specification IPC-4101D and not to name specific products that not everyone can stock.

Secondly, it is easiest to construct multiple layers using the “foil” construction method. Foil construction means that the top and bottom layers (outer) are made from a single piece of copper foil and laminated to the remaining layers with prepreg. In kasta oo ay u ekaan karto mid caqli gal ah in la dhiso PCB 8-lakab ah oo leh afar geesood oo laba gees leh, waxaa la doorbidayaa in marka hore la isticmaalo foil dibadda ah, ka dibna saddex koorso L2-L3, L4-L5, iyo L6-L7. Si kale haddii loo dhigo, qorshee inaad samaysato xidhmooyin dhowr lakab ah si tirada tiirku u noqoto sida soo socota: (tirada guud ee lakabyada laga jaray 2) oo loo qaybiyey 2. Marka xigta, waxaa faa’iido leh in wax laga ogaado guryaha asaasiga ah. Naftooda.

Udub -dhexaadka waxaa lagu keenaa PIECE FR4 oo si buuxda loo bogsaday oo leh naxaas labada dhinac ah. Xargaha waxay leeyihiin dhumuc aad u ballaaran, oo cabbirrada sida badan loo isticmaalo badiyaa waxaa lagu kaydiyaa kaydka waaweyn. Kuwani waa dhumucda ay tahay inaad maanka ku hayso, gaar ahaan markaad u baahan tahay inaad dalbato badeecadaha deg-degga ah si aanad u lumin wakhtiga hoggaaminta ee amarka sugitaanka agab aan caadi ahayn oo ka imanaya qaybiyaha.

Xuddunta birta ee caadiga ah iyo dhumucda naxaasta

Xargaha inta badan loo isticmaalo in lagu dhiso 0.062 “isku -dhufanayayaal qaro weyn waa 0.005”, 0.008 “, 0.014”, 0.021, 0.028 ”, iyo 0.039“. Inventory of 0.047 “is also common, as it is sometimes used to build 2-layer boards. Xudunta kale ee mar walba la keydin doono waa 0.059 gudaha., Maxaa yeelay waxaa loo isticmaalaa in lagu soo saaro boodhadh 2-ply ah oo 0.062 gudaha ah Booskan, waxaan ku xaddidnaa baaxadda naqshadda asaasiga ah oo leh dhumucda magacaaban ee ugu dambeysa ee 0.062 inji.

Dhumucda naxaasta waxay u dhexaysaa nus wiqiyad ilaa saddex ilaa afar wiqiyadood, taas oo ku xidhan isku -darka badeecadda soo saaraha, laakiin kaydka badankiisu wuxuu noqon karaa laba wiqiyadood ama ka yar. Maskaxda ku hay oo xusuusnow in ku dhawaad ​​dhammaan saamiyadu ay isticmaali doonaan culeys naxaas ah labada dhinac ee xudunta. Isku day inaad ka fogaato shuruudaha naqshadeynta PCB ee u baahan naxaas kala duwan dhinac kasta, sida badanaa tani waxay u baahan tahay iibsi gaar ah waxaana laga yaabaa inay u baahan tahay lacag degdeg ah (gaarsiinta degdegga ah), mararka qaarkood xitaa xitaa ma fuliso amarka ugu yar ee qaybiyaha.

For example, if you want to use 1oz of copper on an airplane and plan to use H oz of signal, consider making the airplane in H oz or increasing the signal to 1oz to make the core use both sides like copper with weight. Dabcan, waxaad tan samayn kartaa oo keliya haddii aad weli buuxin karto shuruudaha korantada ee naqshadda oo aad haysato aagag XY ku filan si aad u dejiso xeerarka ballaadhinta raad -raaca/bannaan si aad ula kulanto ugu yaraan 1oz ee lakabka signalada. Haddii aad buuxin karto shuruudahan, waxaa fiican inaad u isticmaasho sida miisaanka naxaasta. Otherwise, you may need to consider a few extra days of lead time.

Adoo u malaynaya inaad dooratay dhumucda asaasiga ah ee habboon iyo miisaanka naxaasta ah, isku -darka kala duwan ee xaashiyaha prepreg ayaa loo adeegsadaa si loo dejiyo meelaha korontada ku haray illaa inta la dhammaystirayo dhumucda loo baahan yahay. Naqshadaha aan u baahnayn xakamaynta impedance, waxaad uga tagi kartaa soo -saaraha ikhtiyaarka prepreg. Waxay isticmaali doonaan nooca ay jecel yihiin ee “caadiga ah”. Dhinaca kale, haddii aad leedahay shuruudo is -diidmo ah, ku sheeg shuruudahan dukumintiga si soo -saaraha uu u hagaajiyo xaddiga prepreg ee u dhexeeya xudunta si uu u buuxiyo qiyamka la cayimay.

Xakamaynta xakamaynta

Haddii loo baahan yahay xakamaynta xannibaadda iyo haddii kale, laguma talinayo inaad isku daydo inaad diiwaangeliso nooca iyo dhumucda prepreg ee goob kasta haddii aadan ku fiicnayn dhaqankan.Often, such detailed stacks eventually need to be adjusted, so they can cause delays. Taa baddalkeeda, jaantuskaaga xidhmooyinku wuxuu muujin karaa dhumucda asaasiga ah ee lammaanaha lakabka gudaha ah wuxuuna tilmaami karaa “booska loo sii diyaariyey ee loo baahan yahay iyadoo lagu saleynayo is -hortaag iyo shuruudaha dhumucda guud”. This allows manufacturers to create ideal laminations to match your design.

Muuqaalka

Xirmooyin ku habboon oo ku saleysan kaydka jira ayaa muhiim u ah in laga fogaado dib -u -dhacyada aan loo baahnayn marka la dalbanayo wareegyo degdeg ah oo leh waqtiyo adag. Inta badan soo -saarayaasha PCB waxay isticmaalaan qaab -dhismeedyo badan oo isku mid ah oo ku salaysan isla kernel -ka tartamayaashooda. Haddii PCB -ga si weyn loo habeeyey mooyee, ma jiro sixir ama dhisme qarsoodi ah. Therefore, it is worth familiarizing yourself with the preferred material for a particular layer and making every effort to design a PCB to match it. Had iyo jeer waxaa jiri doona waxyaabo ka reeban shuruudaha naqshadeynta gaarka ah, laakiin guud ahaan, agabyada caadiga ah ayaa ah doorashada ugu fiican.