Impedance tswj txoj hauv kev hloov pauv PCBs

Nyob rau hauv no blog ncej, peb yuav delve rau hauv lub ntiaj teb no ntawm saj zawg zog PCBs thiab tshawb txog cov txheej txheem sib txawv siv los xyuas kom meej kev pom impedance tswj.

qhia:

Kev tswj hwm impedance yog ib qho tseem ceeb ntawm kev tsim thiab tsim cov ntawv luam tawm yooj yim (Flex PCBs). Raws li cov laug cam tau nrov zuj zus thoob plaws ntau qhov kev lag luam, nws yuav tsum nkag siab txog ntau yam kev tswj hwm impedance muaj.

Dab tsi yog qhov hloov pauv PCB?

Flexible PCB, tseem hu ua hloov pauv hloov hluav taws xob lossis cov khoom siv hluav taws xob hloov tau yooj yim, hais txog cov hluav taws xob hluav taws xob uas nyias nyias, lub teeb thiab hloov tau yooj yim. Tsis zoo li PCBs nruj, uas yog tsim los siv cov ntaub ntawv nruj xws li fiberglass, hloov tau PCBs yog tsim los siv cov ntaub ntawv hloov tau xws li polyimide. Qhov yooj yim no tso cai rau lawv khoov, twist thiab contour kom haum txhua yam duab lossis daim ntawv.

Vim li cas kev tswj hwm impedance tseem ceeb hauv kev hloov pauv PCBs?

Kev tswj hwm impedance yog qhov tseem ceeb hauv kev hloov pauv ntawm PCBs vim nws ua kom muaj kev ncaj ncees ntawm cov teeb liab, txo cov teeb liab poob, thiab txhim kho kev ua haujlwm tag nrho. Raws li qhov kev thov rau cov ntawv thov siv ntau zaus xws li smartphones, ntsiav tshuaj, cov khoom siv, thiab cov khoom siv hluav taws xob tsheb txuas ntxiv nce ntxiv, kev tswj hwm kev tswj hwm impedance tseem ceeb dua.

Impedance tswj txoj kev hloov pauv PCB:

1. Circuit geometry:
Circuit geometry plays lub luag haujlwm tseem ceeb hauv kev tswj impedance. Impedance tuaj yeem raug kho kom zoo los ntawm kev kho qhov dav dav, qhov sib nrug thiab qhov hnyav tooj liab. Kev suav kom raug thiab simulations pab ua kom tiav qhov xav tau tus nqi impedance.

2. Tswj cov khoom siv dielectric:
Qhov kev xaiv ntawm cov khoom siv dielectric cuam tshuam cuam tshuam rau impedance tswj. High-speed saj zawg zog PCBs feem ntau siv cov khoom siv qis-dielectric-constant kom txo cov teeb liab propagation speeds kom ua tiav tswj impedance.

3. Microstrip thiab stripline configurations:
Microstrip thiab stripline configurations yog dav siv rau impedance tswj ntawm saj zawg zog PCBs. Microstrip yog hais txog kev teeb tsa uas cov kab hluav taws xob tau muab tso rau saum npoo ntawm cov khoom siv hluav taws xob, thaum stripline cuam tshuam nrog kev sib tsoo cov kab hluav taws xob ntawm ob txheej dielectric. Ob qho kev teeb tsa muab cov yam ntxwv impedance pom tau.

4. Embedded capacitor:
Embedded capacitors kuj tseem siv los muab cov txiaj ntsig siab capacitance thaum tswj impedance. Kev siv cov khoom siv capacitive xws li cov yeeb yaj kiab pab tswj kom muaj qhov sib npaug ntawm qhov sib npaug ntawm PCB.

5. Kev sib koom ua ke sib txawv:
Kev taw qhia sib txawv yog feem ntau siv hauv kev sib txuas lus ceev thiab xav tau kev tswj hwm impedance. Los ntawm kev sib koom ua ke ntawm qhov sib txawv ntawm qhov sib txawv thiab tswj qhov sib txawv ntawm qhov sib txawv, impedance tuaj yeem tswj tau nruj, txo cov teeb liab kev xav thiab crosstalk.

6. Kev xeem txoj kev:
Kev tswj hwm impedance yuav tsum tau ua nruj me ntsis kev ntsuam xyuas thiab xyuas kom ntseeg tau tias ua raws li cov qauv tsim tshwj xeeb. Cov thev naus laus zis xws li TDR (Time Domain Reflectometry) thiab cov ntsuas impedance yog siv los ntsuas thiab txheeb xyuas qhov tseem ceeb ntawm impedance ntawm ntau zaus.

nyob rau hauv xaus:

Kev tswj hwm impedance yog ib qho tseem ceeb ntawm kev tsim cov PCBs hloov tau raws li cov kev xav tau ntawm kev siv hluav taws xob niaj hnub. Cov kws tsim khoom tuaj yeem ua tiav qhov kev tswj xyuas impedance zoo los ntawm kev siv qhov tsim nyog Circuit Court geometry, tswj cov khoom siv hluav taws xob, cov kev teeb tsa tshwj xeeb xws li microstrip thiab stripline, thiab cov tswv yim xws li cov khoom siv hluav taws xob thiab cov khoom sib txawv. Kev soj ntsuam zoo thiab kev siv tau ua lub luag haujlwm tseem ceeb hauv kev ua kom ntseeg tau qhov tseeb ntawm impedance thiab kev ua haujlwm. Los ntawm kev nkag siab txog cov kev tswj hwm impedance no, cov tsim qauv thiab cov chaw tsim khoom tuaj yeem muab cov PCB txhim khu kev qha thiab ua haujlwm siab rau ntau yam kev lag luam.