Gwaro reKuisa PCB Decoupling Capacitor

Kuisa capacitor muchikamu chimwe chete hakusi kungova pedyo neIC chete - asi kuderedza kupinza kwe current loop kubva ku capacitor kuenda ku power pin. Capacitor yakaiswa 2 mm kure ne power pin isina kugadzirwa zvakanaka inogona kuita zvakaipa kupfuura yakaiswa 5 mm kure ne 5 mm yakagadziridzwa kuburikidza ne geometry.

🕑 Kuverenga kwemaminitsi gumi nemashanu | Danho: Rakafambira Mberi | Yakagadziridzwa: Chivabvu 2025 | Chikamu che: Gwaro rekugadzira Simba rePCB

Zviri Mukati

1. Nei Kuisa Nzvimbo Kuchikosha Kupfuura Kusarudza Kukosha
2. Kukwidza Inductance: Iyo Parameter Inokosha
3. Kuburikidza neDhizaini yeDecoupling Capacitors
4. Kugadzirisa Magadzirirwo Emajiometri ePad uye Kugadzirisa Mafambiro Etsoka
5. Mitemo yekuisa nerudzi rweIC Package
6. Kusarudzwa kweKukosha kweCapacitor uye Frequency Inoshanda
7. Zvikanganiso Zvakajairika Pakuisa uye Kugadzirisa
8. Mibvunzo Inonyanya Kubvunzwa

Gwaro iri rinotarisa pakuiswa kwe capacitor, kuburikidza nedhizaini, uye geometry yemapad - sarudzo dzemagadzirirwo emuviri dzinoona kana nzira yako yekuparadzanisa ichishanda zvechokwadi. Kuti uwane hurongwa hwakakura hwesimba remagetsi hunosanganisira PDN impedance targets uye dhizaini yeplane, ona gwara guru rePCB power integrity design.

1) Nei Kuisa Nzvimbo Kuchikosha Kupfuura Kusarudza Kukosha

Mainjiniya mazhinji anopedza nguva yakawanda achisarudza kubatanidza ma capacitor uye nguva shoma pakuisa - asi kuisa ndiko kunonyanya kukonzera kushanda kwema frequency akawanda.

Kapitori yega yega yekuparadzanisa ine frequency inozviratidza pachayo (SRF) inoenderana ne capacitance yayo uye total effective series inductance yayo (ESL). Pamusoro peSRF, kapitori inova inductive uye haipe purofiti yekuparadzanisa. ESL yese inosanganisira:

• Pakeji yeESL: Yakagadziriswa nehukuru hwemuviri — 0201 ≈ 0.2–0.4 nH; 0402 ≈ 0.4–0.8 nH; 0603 ≈ 0.8–1.5 nH
• Pad uye trace inductance: 0.5–2 nH zvichienderana nehurefu hwetrace pakati pe capacitor pads nema vias
• Kuburikidza ne inductance: 0.5–1 nH pa via pa mm ye via kureba mu dielectric
• Kupararira kwemhepo mundege: 0.1–0.5 nH kubva pakupararira kwemagetsi mundege kuenda kuIC power pin

Capacitor ye100 nF ine SRF ye50 MHz zvichibva papakeji yeESL chete inogona kuva neSRF inoshanda ye20 MHz chete mushure mekuwedzera 1 nH kuburikidza ne inductance. Kuiswa kwakakodzera kunobvisa trace inductance isingakoshi kunodzoreredza huwandu hwema frequency aya.

2) Kukwidza Kupinza: Chikamu Chinokosha

Kuisa inductance (L _mount ) ndiko kutenderera kwese kwenzira iripo kubva pa capacitor kuburikidza ne vias kuenda ku power plane, kuburikidza ne plane kuenda ku IC power via, uye kudzokera kuburikidza ne GND plane kuenda ku capacitor GND via.

Kukwidza Inductance vs Nzvimbo Yekuisa

Kuverenga Via Mounting Inductance

L _{kuburikidza ne} ≈ 5.08 × h × [ln(4h/d) + 1] pH

Apo h = kuburikidza nehurefu kuburikidza ne dielectric mumainchi uye d = dhayamita yekuboorera mumainchi. Muenzaniso: 1.6 mm board, 0.3 mm drill → L _kuburikidza ≈ 1.1 nH per via.

3) Kuburikidza neDhizaini yeKubvisa MaCapacitor

Magadzirirwo mana anoshandiswa mukuita, kubva pane akaipa kusvika pakushanda kwakanakisa:

Kugadziriswa 1 — Single Via, Kuiswa Kure (Dzivisa)

Imwe kuburikidza neimwe neimwe yePWR neGND yakaiswa pamagumo etrace. Trace inductance inowedzera kuburikidza neinductance, ichisundira SRF inoshanda pasi pe20 MHz kune akawanda ma capacitor e100 nF. Inogamuchirwa chete kune ma capacitor ane frequency yakaderera.

Kugadziriswa 2 — Kuburikidza nePad (Standard)

Mavhiya akaiswa pedyo nepadhi yega yega ye capacitor, chidimbu chidiki pakati pepadhi ne via. Trace inductance yakaderedzwa kusvika 0.1–0.3 nH. Chidimbu chinogamuchirwa kune ma capacitor anoshanda pamusoro pe50 MHz. Kupfuura nepakati-ku-pad daro remupendero harifanirwe kudarika 0.3 mm.

Kugadziriswa 3 — Dogbone Via (Kushanda Kwakanyanya)

Mavhiya maviri pa capacitor imwe neimwe, imwe pad imwe neimwe, akaiswa pedyo nemadhiya sezvinobvumirwa neDRC, nemavhiya ePWR neGND ari kumativi akasiyana emuviri we capacitor. Inogadzira current loop pfupi inogoneka. Inoshanda kusvika ku200–500 MHz ine ma capacitor e0402.

Kugadziriswa 4 — Via-in-Pad (Kushanda Kwakanyanya)

Iyo via inoiswa zvakananga mukati me capacitor pad. Inobvisa zvese zvinobuda pad-to-via trace inductance. Inoda ma vias akazadzwa, akavharirwa, uye akarongwa. Inowedzera inenge 15–25% pamutengo wekugadzira PCB. Yakajairika yemabhodhi anomhanyisa kupfuura 1 Gbps. Ona gwara redu rekugadzira nekugadzira via-in-pad.

Mavhiza Akawanda muParallel

Ma-vias maviri ari pamwe chete anoderedza inductance inoshanda kusvika painenge 60% ye-via imwe chete. Ma-vias matatu ari pamwe chete: anenge 45%. Kune ma-capacitor ane simba guru (47 µF zvichikwira), shandisa ma-vias maviri kusvika mana papad imwe neimwe kuderedza inductance uye kuramba kupisa.

4) Kugadzirisa Magadzirirwo Emajiyomethri Epad uye Kugadzirisa Mafambiro Etsoka

Kune ma capacitor e0402 anoshandiswa pamusoro pe100 MHz, deredza urefu hwepad kubva paIPC standard 0.8 mm kusvika pa0.5–0.6 mm. Izvi zvinoderedza trace inductance inoshanda ne0.1–0.2 nH uku uchichengetedza kugona kusungirirwa kwakakwana. Simbisa chero shanduko yetsoka nemumwe wako wekugadzira usati wagadzira.

Kuwedzera upamhi hwemapedhi kubva pa 0.5 mm kusvika 0.7–0.8 mm yema capacitor ekubvisa simba kunoderedza inductance neinenge 15–20% pasina muripo wekugadzira.

Deredza gomba rekuvhura (anti-pad) munzvimbo dzisina kubatana kusvika pa 0.1–0.15 mm kupfuura dhayamita yekuboorera. Ma anti-pads akakura anoderedza kugona kweplane uye anowedzera zvishoma kupararira kweinductance.

5) Mitemo yekuisa nerudzi rweIC Package

Mapakeji eBGA

Mabhora emagetsi eBGA ari mukati mechikamu chechikamu. Kune 1.0 mm pitch zvichikwira: isa ma capacitor e0201 zvakananga pasi peBGA pakati pemabhora. Kune ese ma pitches: isa ma capacitor emutsara wekutanga mukati me1–2 mm kubva pabhora remagetsi riri pedyo. Kune fine-pitch BGA pa0.65 mm uye pasi: shandisa via-in-pad paBGA escape vias yakasanganiswa nema capacitor e0201 kunze kwemuganhu wechikamu. Ona gwara redu reBGA PCB assembly.

Mapakeji eQFN

Mapakeji eQFN anoisa power pad iri pakati pepasi. Isa macapacitor ekuparadzanisa padyo neperimeter yepower pad, nemavias achibatana nemagetsi emukati zvakananga pasi peQFN thermal pad.

Zvinobatanidza Simba Rinoburitswa Nepaburi

Isa ma capacitor ekubatanidza zvinhu zvakawanda (47–470 µF) mukati me10 mm kubva pamapini ekubatanidza pane imwe layer. Isa kusanganisa zvinhu zvakawanda (100 nF) pakati pema capacitor ekubatanidza zvinhu zvakawanda nenzira inotakurwa zvinhu.

6) Kusarudzwa kweValue yeCapacitor uye Frequency Inoshanda

SRF = 1 / (2π × √(C × L _huwandu )) apo _huwandu hweL = package ESL + inductance yekumisikidza.

Shandisa kanenge makumi matatu emakumi emakumi emakumi emakumi emakumi emagetsi kuti uve nechokwadi chekuti chiteshi chimwe chete chinofukidza chiteshi. Zvisinei nekuti chiteshi chimwe chete che capacitor, chiri pedyo neIC, chinosiya mipata yakakura yefrequency muPDN impedance profile.

7) Zvikanganiso Zvakajairika Pakuisa uye Kugadzirisa

8) Mibvunzo Inowanzobvunzwa

Ko capacitor yekuparadzanisa inofanira kunge iri padanho rimwe chete neIC here?

Ehe, kana zvichibvira. Kuisa mativi akasiyana kunoda kuti current loop ipfuure ukobvu hwebhodhi rose kaviri, zvichiita kuti iite kaviri kuburikidza ne inductance. Kune ma assemblies ane mativi maviri uko kuisa mativi akasiyana kusingadzivisiki, shandisa via-in-pad kuderedza mupiro we via inductance.

Capacitor yekuparadzanisa inofanira kuva pedyo zvakadii neIC?

Chinokosha kuisa inductance, kwete daro chairo. Capacitor iri kure ne5 mm ine via-in-pad uye 0201 package inogona kupa connection iri nani pane 0603 capacitor iri kure ne1 mm ine trace refu kuenda kune remote via. Kune ma capacitor anotarisa pamusoro pe100 MHz: chengeta daro re via-to-pad riri pasi pe0.5 mm uye capacitor iri mukati me3 mm kubva paIC power pin.

Ndingashandisa capacitor imwe chete hombe panzvimbo pemadiki akawanda here?

Capacitor imwe chete hombe inopa mukana wakanaka wekuparadzanisa mafrequency mashoma asi inosiya PDN isina dziviriro pamusoro peSRF yayo. Macapacitor akawanda ari pamwe chete — kunyanya akasiyana — anopa bandwidth yakakura. Musanganiswa we10 µF + 100 nF + 10 nF unofukidza bandwidth yakawanda kanenge ka100 kupfuura chero capacitor imwe chete.

Ndeipi mhando ye dielectric yandinofanira kushandisa pakupatsanura ma capacitor?

Shandisa X7R kana X5R dielectric MLCCs pakubvisa simba. Dzivisa Y5V dielectric — capacitance yayo inoderedza 70–80% pasi peDC bias, saka chivharo che10 µF Y5V chinogona kupa 2–3 µF chete pamagetsi ari kushanda. C0G (NP0) ine kugadzikana kwakanaka asi inowanikwa chete muzviyero zvidiki uye inonyanya kushandiswa pakusefa RF.

Ko ma capacitor ekuparadzanisa anofanira kushandisa thermal relief kana kuti direct connect kune power plane here?

Shandisai zvakananga zvinongedzo nguva dzose. Maspokes ekupisa anowedzera 0.5–2 nH ye inductance nekuda kwehutete hwespokes, zvichideredza zvakanyanya mashandiro e high-frequency. Chengetedzai thermal relief yezvinhu zvinoda kusungirirwa nemaoko kana kuti kupinda mu-circuit testing.

Kuti uwane hurongwa hwakazara hwesimba — kuverenga kwePDN impedance, dhizaini yeplane yesimba, uye kutonga kweSSN — ona gwara redu rekugadzira simba rePCB . Kuti uwane zvinodiwa pakugadzira kuburikidza nepad, bata Highleap Electronics.

Kuisa capacitor zvakanaka kwakakosha pakuchengetedza mashandiro ePDN uye kuderedza kumhanya kwemagetsi ane frequency yakakwira. Nekufunga zvakanyatsonaka nezvekuisa inductance, kuburikidza ne geometry, dhizaini yemapad, uye kuva pedyo nemapini emagetsi eIC, mainjiniya vanogona kugadzirisa frequency inoshanda yekuzvitenderedza uye kuve nechokwadi chekuti impedance inovharwa nguva dzose mu power rail. Kushandisa nzira dzepamusoro dzakadai se via-in-pad kana multiple parallel vias kunoderedzawo loop inductance uye kunowedzera kushanda kwe decoupling, zvichitsigira magadzirirwo ePCB ane speed yakakwira uye high-density. Kuitwa kwakakodzera kwenheyo idzi kwakakosha kuti simba rive rakavimbika mumabhodhi emazuva ano e multilayer.