PCB电磁兼容设计(马双武4h)

2PCBSI3PCBTdtrtr=d+tr10.5t∑∞=Φ++=1)2(cos)(nnntTnCTtVπτTtnTtnTnTnTCrrnππτπτπτ)sin()sin(2=Ttnrn)(+−=ΦτπV(t)4PCBC1=2/TC2=0.64/TfC3=0.2/Ttrf21/π1/πtr-20dB/dec-40dB/decC1C2C35PCB3nS5nS10nS9nS50nSSTTLLSTTLTTLHCMOSCMOS6PCBI13247PCBHzd=0.65cm10cm1md=0.27cm10cm1md=0.06cm10cm1md=0.04cm10cm1m10Hz51.4µ517µ327µ3.28m5.29m52.9m13.3m133m1k429µ7.14m632µ8.91m5.34m53.9m14m144m100k42.6m712m54m828m71.6m1.090.3m1.071M426m7.12540m8.28714m10783m10.65M2.1335.52.741.33.57503.865310M4.2671.25.482.87.141007.710650M21.33562741435.750038.5530100M42.65471.477150M63.981107115E=KfLI––E=Kf2AI11PCB=KfAHZGZLV~H–––12PCBHHDtrace1trace22)(1),(HDLtKr+=15PCB3W16PCB3WWWWWWWW3W3W17PCB3WWWWW2WWW2WW18PCB19PCB20PCB21PCB22PCB23PCB24PCB25PCB26PCB27PCBrGroundGroundS1S2S3S428PCB29PCBPCBPCBTopGroundPowerBottomTopGroundPowerBottomTopGroundPowerBottomS1S2TopGroundPowerBottomS1S2TopGroundPowerBottomGroundS1TopGroundPowerBottomGroundS1S2S3TopGroundPowerBottomGroundGroundS1S2TopGroundPowerBottomGroundGroundS1S3S2S4TopGroundPowerBottomGroundGroundS1S4S2S3TopGroundPowerBottomGroundGroundS1S3S2Ground20H20H3mm20H20H20HDigitalpowerAnalogpowerDigitalgroundAnaloggroundMoat394041bad42ÔÔÔ()Ô47PCBr48PCB☯☯VCCCICEVCCÔÔÔÔÔCLRCZfofZfLCfoπ21=LCIVCCVtIC∆∆⋅∆=tICVVCCCICEVCCI=20mAC=2nFt=10nSV=100mVVCCgoodpoor60SISI61SI62SISIÒreflectionÒcross-talkÒ/groundbounce63SI64SISIIC65SI66SIDelayrTt6≤)(3)(nstcmlr≥or90%10%RiseTimePropagationDelay()6*l67xx+dxGLRCuiu+dui+di68))((CjGLjRωωγ++=tiLRixu∂∂+=∂∂−CjGLjRZcωω++=γtuCGuxi∂∂+=∂∂−------)(tjeωcZ-----ILjRdxdU)(ω+=−xxebeaxUγγ+=−)()(1)(xxcebeaZxIγγ−=−UCjGdxdI)(ω+=−a,b690xtXU0I0U(x)I(x)UtItZtcZ,γ)sinh()cosh()()sinh()cosh()(0000xZUxIxIxZIxUxUccγγγγ−=−={)sinh()cosh()()sinh()cosh()(1111xZUxIxIxZIxUxUcttcttγγγγ+=+={(x1=t-x)70)()()(xIxUxZ=)tanh()(1nxZxZc+=γxtxZZnct−==1)tanh(71)tanh()(1xZxZcγ=)(2LCjjωβλπβγ===)2tan()(1xZjxZcλπ=7200.10.20.30.40.50.60.70.80.91012345678910x1/λabs(Z(x)/Zc)73∞===nZZnct1)tanh(cccZZnxZxZ=∞=+=)tanh()tanh()(1γ74LCV1==βωLCVtpd==1750xtXU0U(x)UtItZtcZ,γUiUrriUUxU+=)(irUU=ΓctctZZZZ+−=Γ0=→=rctUZZ76777879ftnstrpd/67.0475.0017.1+=εmilsWforohmsTWHZr25158.098.5ln41.1870++=εmilsWforohmsTWHZr1558.098.5ln41.1790++=ε151rε0.31.0HWWTH80THrεWH1ohmsTWHZr+=8.098.5ln87'0ε−−=HHrr155.1exp1'εεftnstrpd/017.1'ε=0.31.0HW151rε81wHHTohmsTWTHZr++=8.0)2(9.1ln600εftnstrpd/017.1ε=0.21.0HW25.0HT151rε82wswTrεhohmseZZhsdiff)48.01(296.00−−≈ohmsTWhZr++=)8.0(67.04ln67.0475.0600ε83wswhohmseZZhsdiff−≈−9.20374.012ohmsTWhZr+=)8.0(67.04ln600πε84–858687•RT=Z’0CT~20-600pF88Z0VccR1R2021//ZRR→89Z0Vcc•••90pinICtracepadgroundviapinICtracepadgroundvia391PrintedCircuitBoardDesignTechniquesforEMCComplianceEMCandtheprintedcircuitboard,MarkI.MontroseHighspeeddigitaldesign-Ahandbookofblackmagic,HOWARDW.JOHNSON••••••