Nyob rau hauv cov txheej txheem kev kawm ntawm high-speed PCB tsim, crosstalk yog ib qho tseem ceeb lub tswv yim uas yuav tsum tau mastered. Nws yog txoj hauv kev tseem ceeb rau kev nthuav tawm ntawm electromagnetic cuam tshuam. Asynchronous teeb liab kab, cov kab tswj, thiab I\ O chaw nres nkoj raug xa mus. Crosstalk tuaj yeem ua rau kev ua haujlwm tsis zoo ntawm cov khoom siv hluav taws xob lossis cov khoom siv.

Crosstalk

Hais txog qhov tsis xav tau qhov hluav taws xob tsis muaj suab nrov cuam tshuam ntawm cov kab sib txuas uas nyob ib sab vim electromagnetic coupling thaum lub teeb liab nthuav tawm ntawm cov kab sib kis. Qhov kev cuam tshuam no yog tshwm sim los ntawm kev sib nrig sib inductance thiab kev sib nrig sib capacitance ntawm cov kab sib kis. Qhov tsis sib xws ntawm PCB txheej, lub teeb liab kab sib nrug, cov yam ntxwv hluav taws xob ntawm qhov kawg ntawm kev tsav tsheb thiab qhov kawg tau txais, thiab txoj kev txiav txoj kab tag nrho muaj qee yam cuam tshuam rau crosstalk.

Cov kev ntsuas tseem ceeb los kov yeej crosstalk yog:

Ua kom qhov sib txawv ntawm cov xaim sib txuas thiab ua raws li txoj cai 3W;

Ntxig ib qho av sib cais ntawm cov kab sib txuas;

Txo qhov kev ncua deb ntawm txheej thaiv kab thiab lub dav hlau hauv av.

Yuav kom txo tau crosstalk ntawm kab, kab sib nrug yuav tsum loj txaus. Thaum cov kab nruab nrab qhov sib nrug tsis tsawg dua 3 npaug ntawm kab dav, 70% ntawm cov hluav taws xob tuaj yeem khaws cia yam tsis muaj kev cuam tshuam, uas yog hu ua 3W txoj cai. Yog tias koj xav ua kom tiav 98% ntawm qhov hluav taws xob tsis muaj kev cuam tshuam rau ib leeg, koj tuaj yeem siv qhov sib txawv ntawm 10W.

Lus Cim: Hauv kev tsim PCB tiag tiag, txoj cai 3W tsis tuaj yeem ua tau raws li qhov yuav tsum tau ua kom zam dhau kev sib tham.

Txoj hauv kev kom tsis txhob crosstalk hauv PCB

Txhawm rau kom tsis txhob muaj kev sib tham hauv PCB, cov kws tshaj lij tuaj yeem txiav txim siab los ntawm cov txheej txheem ntawm PCB tsim thiab teeb tsa, xws li:

1. Muab cov cuab yeej logic series raws li kev ua haujlwm thiab khaws cov qauv tsheb npav hauv kev tswj xyuas nruj.

2. Txo qhov kev ncua deb ntawm lub cev ntawm cov khoom.

3. Cov kab hluav taws xob ceev ceev thiab cov khoom siv (xws li siv lead ua oscillators) yuav tsum nyob deb ntawm I / () kev sib txuas sib txuas thiab lwm qhov chaw uas muaj kev cuam tshuam rau cov ntaub ntawv cuam tshuam thiab kev sib txuas.

4. Muab qhov kev txiav txim kom raug rau txoj kab kev kub ceev.

5. Tsis txhob ncua cov kab nyob deb uas sib npaug rau ib leeg thiab muab qhov sib nrug txaus ntawm cov kab sib txuas kom txo qis inductive coupling.

6. Cov xaim ntawm cov khaubncaws sab nraud povtseg (microstrip lossis stripline) yuav tsum yog qhov sib npaug rau ib leeg kom tiv thaiv kev sib txuas ntawm cov txheej txheem capacitive.

7. Txo qhov kev ncua deb ntawm lub teeb liab thiab lub dav hlau hauv av.

8. Kev sib cais thiab kev sib cais ntawm cov suab nrov emissions ( moos, I / O, kev sib txuas ceev ceev), thiab cov teeb liab sib txawv tau muab faib ua ntau txheej.

9. Ua kom qhov kev ncua deb ntawm cov kab teeb liab kom ntau li ntau tau, uas tuaj yeem txo qhov kev sib tw capacitive.

10. Txo cov hlau lead inductance, tsis txhob siv cov impedance loads siab heev thiab tsawg impedance loads nyob rau hauv Circuit Court, thiab sim stabilize lub load impedance ntawm analog Circuit Court ntawm loQ thiab lokQ. Vim hais tias lub siab impedance load yuav ua rau kom lub capacitive crosstalk, thaum siv heev impedance load, vim lub siab tshaj kev khiav hauj lwm voltage, lub capacitive crosstalk yuav nce, thiab thaum siv heev tsawg impedance load, vim lub loj khiav hauj lwm tam sim no, lub inductive Crosstalk yuav. nce.

11. Npaj cov teeb liab ceev ceev ntawm cov txheej txheem hauv PCB.

12. Siv impedance txuam tshuab los xyuas kom meej qhov tseeb ntawm BT daim ntawv pov thawj teeb liab thiab tiv thaiv overshoot.

13. Nco ntsoov tias rau cov teeb liab nrog cov npoo nrawm nrawm (tr≤3ns), ua cov txheej txheem tiv thaiv kab mob xws li qhwv hauv av, thiab npaj qee cov kab teeb liab uas cuam tshuam los ntawm EFT1B lossis ESD thiab tsis tau lim ntawm ntug ntawm PCB. .

14. Siv lub dav hlau hauv av kom ntau li ntau tau. Cov kab teeb liab uas siv lub dav hlau hauv av yuav tau txais 15-20dB attenuation piv rau cov kab teeb liab uas tsis siv lub dav hlau hauv av.

15. Cov teeb liab siab zaus thiab cov teeb liab rhiab heev yog ua tiav nrog hauv av, thiab siv cov cuab yeej siv hauv av hauv ob lub vaj huam sib luag yuav ua tiav 10-15dB attenuation.

16. Siv cov xov hlau sib npaug, thaiv cov xov hlau lossis cov xov hlau coaxial.

17. Lim cov kab teeb liab thab plaub thiab kab rhiab.

18. Teem txheej txheej thiab xaim tsim nyog, teeb tsa cov txheej txheem thiab cov kab sib txuas sib txuas kom tsim nyog, txo qhov ntev ntawm cov teeb liab sib npaug, txo qhov kev ncua deb ntawm lub teeb liab txheej thiab lub dav hlau txheej, ua kom qhov sib nrug ntawm cov kab teeb liab, thiab txo qhov ntev ntawm cov kab sib txuas. Cov kab teeb liab (hauv qhov ntev ntawm qhov tseem ceeb), cov kev ntsuas no tuaj yeem txo cov lus sib tham.