Kab dav yog dab tsi?

Cia peb pib nrog qhov pib. Dab tsi yog txoj kab dav? Vim li cas nws thiaj tseem ceeb uas yuav tsum qhia kom meej ib qho kab dav dav? Lub hom phiaj ntawm PCB thaiv yog txhawm rau txuas txhua yam teeb liab hluav taws xob (analog, digital lossis fais fab) los ntawm ib qho mus rau lwm qhov.

Lub node tuaj yeem yog tus pin ntawm cov khoom siv, ib ceg ntawm cov kab loj dua lossis dav hlau, lossis lub ncoo khoob lossis qhov ntsuas ntsuas rau kev tshuaj xyuas. Cov kab dav dav feem ntau ntsuas hauv mils lossis ntau txhiab ntiv tes. Kev thaiv dav dav dav rau cov cim zoo ib yam (tsis muaj qhov tshwj xeeb xav tau) yuav yog ob peb ntiv tes ntev hauv 7-12 mils ntau, tab sis ntau yam yuav tsum tau txiav txim siab thaum txiav txim siab qhov dav dav thiab ntev.

Daim ntawv thov feem ntau tsav cov kab dav thiab hom thaiv hauv PCB tsim thiab, ntawm qee kis, feem ntau sib npaug PCB kev tsim nqi, pawg thawj coj/qhov loj, thiab kev ua tau zoo. Yog tias lub rooj tsavxwm muaj cov qauv tsim tshwj xeeb, xws li kev ua kom nrawm dua, suab nrov lossis tshem tawm kev sib txuas, lossis siab tam sim no/qhov hluav taws xob, qhov dav thiab hom kev taug yuav yog qhov tseem ceeb tshaj li ua kom zoo dua tus nqi tsim khoom ntawm PCB liab qab lossis tag nrho pawg thawj coj loj.

Cov lus qhia tshwj xeeb ntsig txog thaiv hauv PCB tsim khoom

Typically, the following specifications related to wiring begin to increase the cost of manufacturing bare PCB.

Kev tsim qauv ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom ntom tuaj yeem ua tau zoo heev, yog li yuav tsum tau kho qhov tob ntawm 2.5m lossis ntau dua lossis ntau dua, raws li laser drilled microthrough-qhov. Hloov pauv, qee qhov kev tsim hluav taws xob siab yuav xav tau cov hlua loj lossis dav hlau, siv tag nrho cov txheej thiab nchuav cov ooj uas tuab dua li tus qauv. Hauv qhov chaw txwv tsis pub siv, cov phaj nyias nyias uas muaj ob peb txheej thiab txwv cov tooj liab ua kom tuab ntawm ib nrab ounce (0.7 mil tuab) yuav xav tau.

Hauv lwm qhov xwm txheej, kev tsim kom muaj kev sib txuas lus nrawm los ntawm ib qho txuas mus rau lwm qhov yuav xav tau txuas nrog kev tswj hwm qhov tsis txaus thiab qhov dav tshwj xeeb thiab sib nrug ntawm ib leeg kom txo qis kev xav thiab kev sib koom ua ke. Lossis qhov tsim qauv yuav xav tau qee qhov ntev kom phim lwm cov cim tseem ceeb hauv lub npav. Cov ntawv thov hluav taws xob siab xav tau qee yam kev nyab xeeb, xws li txo qis qhov nruab nrab ntawm ob qhov kev sib txawv qhia tawm los tiv thaiv kev sib tw. Tsis hais tus yam ntxwv lossis tus yam ntxwv, taug qab cov ntsiab lus tseem ceeb, yog li cia peb tshawb xyuas ntau yam kev thov.

Ntau txoj kab dav thiab tuab

PCBS typically contain a variety of line widths, as they depend on signal requirements. Cov kab me me uas pom tau yog rau lub hom phiaj TTL (transistor-transistor logic) qib cov cim thiab tsis muaj qhov tshwj xeeb xav tau rau tam sim no lossis tiv thaiv suab nrov.

Cov no yuav yog hom kab hluav taws xob feem ntau ntawm lub rooj tsavxwm.

Cov kab hluav taws xob tau tuab dua tau ua kom zoo rau lub peev xwm nqa tam sim no thiab tuaj yeem siv rau cov khoom siv hluav taws xob lossis lub zog ntsig txog kev ua haujlwm uas xav tau lub zog siab dua, xws li kiv cua, lub cev muaj zog, thiab kev xa hluav taws xob tsis tu ncua mus rau cov khoom qis dua. Sab saud sab saud ntawm daim duab txawm qhia pom lub teeb liab sib txawv (USB kev kub ceev) uas piav qhia qhov sib nrug tshwj xeeb thiab dav kom tau raws li qhov xav tau ntawm 90 ω. Daim duab 2 qhia me ntsis ntu ntu ntu ntawm pawg thawj coj saib xyuas uas muaj rau txheej thiab xav tau BGA (pob kab sib chaws sib dhos) sib dhos uas xav tau cov hlua txuas ntxiv.

Yuav xam cov kab dav dav hauv PCB li cas?

Cia peb nqis los ntawm cov txheej txheem ntawm kev suav qee qhov dav dav rau lub teeb liab lub zog uas hloov pauv tam sim no los ntawm cov khoom siv hluav taws xob mus rau ib qho khoom siv ib puag ncig. Hauv qhov piv txwv no, peb yuav suav qhov dav kab dav dav ntawm txoj kab hluav taws xob rau DC lub cav. Txoj kev fais fab pib ntawm lub fuse, hla H-choj (cov khoom siv los tswj kev xa hluav taws xob hla DC lub tshuab cua), thiab txiav tawm ntawm qhov txuas ntawm lub cav. Qhov nruab nrab txuas ntxiv qhov siab tshaj tam sim no xav tau los ntawm DC lub cav yog li 2 amperes.

Tam sim no, PCB thaiv ua raws li tus tiv thaiv, thiab ntev dua thiab nqaim dua cov thaiv, qhov kev tiv thaiv ntxiv tau ntxiv. Yog hais tias thaiv tsis tau hais qhia kom raug, qhov siab tam sim no yuav ua rau cov kab hluav taws xob puas tsuaj thiab/lossis ua rau muaj qhov hluav taws xob poob qis rau lub cav (ua rau txo qis). Yog tias peb xav tias qee qhov xwm txheej dav dav, xws li 1 ooj tooj liab nchuav thiab kub hauv chav thaum lub sijhawm ua haujlwm ib txwm muaj, peb yuav tsum suav qhov kab dav dav yam tsawg kawg nkaus thiab qhov kev cia siab yuav poob ntawm qhov dav ntawd.

PCB kab nrug thiab ntev

Txog kev tsim qauv digital nrog kev sib txuas lus nrawm, tshwj xeeb qhov sib txawv thiab hloov kho qhov ntev yuav xav tau kom txo qis kev sib tshuam, sib txuas, thiab rov xav dua. Rau lub hom phiaj no, qee qhov kev siv yog USB-raws cov cim sib txawv cim thiab RAM-raws qhov sib txawv sib txawv cov cim. Feem ntau, USB 2.0 yuav xav tau kev sib txawv ntawm 480Mbit/s (USB chav kawm ceev) lossis siab dua. Qhov no yog ib nrab vim tias USB-high-speed feem ntau ua haujlwm qis dua qhov sib txawv thiab sib txawv, nqa tag nrho cov teeb liab theem ze rau lub suab nrov tom qab.

Muaj peb yam tseem ceeb los txiav txim siab thaum xa cov kab hluav taws xob USB nrawm: xaim dav, ua qhov sib nrug, thiab ntev cable.

Tag nrho cov no yog qhov tseem ceeb, tab sis qhov tseem ceeb tshaj plaws ntawm peb yog kom paub tseeb tias qhov ntev ntawm ob kab sib phim kom ntau li ntau tau. As a general rule of thumb, if the lengths of the cables differ from each other by no more than 50 mils, this significantly increases the risk of reflection, which may result in poor communication. 90 ohm sib piv qhov tsis txaus ntseeg yog qhov dav dav tshwj xeeb rau kev sib txuas sib txuas sib txuas. Txhawm rau ua tiav lub hom phiaj no, txoj hauv kev yuav tsum tau ua kom zoo dua hauv qhov dav thiab qhov sib nrug.

Daim duab 5 qhia txog qhov piv txwv ntawm kev sib txawv sib txawv rau kev xaim hluav taws xob USB cuam tshuam uas muaj 12 lab dav txuas hauv 15 lab sib nrug.

Interfaces for memory-based components that contain parallel interfaces will be more constrained in terms of wire length. Feem ntau high-end PCB tsim software yuav muaj peev xwm hloov kho qhov ntev uas ua kom zoo ntawm kab ntev kom phim txhua qhov kev cuam tshuam cuam tshuam hauv kev caij npav. Daim duab 6 qhia qhov piv txwv ntawm DDR3 kev teeb tsa nrog kev hloov kho qhov ntev.

Cov kab thiab cov dav hlau ntawm kev sau av

Qee cov ntawv thov uas muaj cov khoom tiv thaiv suab nrov, xws li cov wireless chips lossis antennas, yuav xav tau kev tiv thaiv me ntsis ntxiv. Kev tsim cov thaiv thiab dav hlau nrog rau qhov av hauv av tuaj yeem pab txo qis kev sib txuas ntawm cov xov hluav taws xob nyob ze lossis xaiv lub dav hlau thiab cov cim qhia tawm ntawm lub nkoj uas nkag mus rau ntawm ntug ntawm pawg thawj coj.

Figure 7 shows an example of a Bluetooth module placed near the edge of the plate, with its antenna outside a thick line containing embedded through-holes connected to the ground formation. Qhov no pab cais cov kav hlau txais xov los ntawm lwm lub voj voos thiab dav hlau.

This alternative method of routing through the ground can be used to protect the board circuit from external off-board wireless signals. Daim duab 8 qhia txog lub suab nrov-cuam tshuam nrog PCB nrog lub hauv paus nkag los ntawm lub qhov dav hauv lub dav hlau raws ib puag ncig ntawm pawg thawj coj saib.

Cov kev coj ua zoo tshaj plaws rau PCB thaiv

Ntau yam txiav txim siab tus yam ntxwv thaiv ntawm PCB thaj chaw, yog li nco ntsoov ua raws li kev coj ua zoo tshaj plaws thaum txuas koj lub PCB tom ntej, thiab koj yuav pom qhov sib npaug ntawm PCB tus nqi fab, kev sib tw hauv Circuit Court, thiab kev ua haujlwm tag nrho.