高速PCB设计指南之二

PCBPCB(HD)″″1))“”“”″″“”“”()-1-PCB()()()IEC-0.60.40.2-0.00.00.0-0.10.00.00.50.250.050.50.050.05()(:mm)IEC-0.80.50.2-0.50.350.2-0.050.050.030.50.250.050.50.050.05L(0.625mm)(:mm)J(:mm)-0.20.20.2-0.80.60.4-0.10.050.01.50.80.20.50.050.05MELF(:mm)-1.00.40.2-0.20.10.0-0.20.10.0-2-PCB0.20.250.250.50.050.05(:mm)-0.20.10-0.20.10-0.20.100.250.10.050.50.050.05L(:mm)-0.10.10.0-1.00.50.2-0.10.10.10.50.250.050.50.050.052BGACAP“”3BGA“”“”“”(“”)()″-3-PCB()4()µ*µµ“”µ5“”BGA(mm)-0.050.250.300.350.25-0.300.650.250.300.350.25-0.300.650.350.400.450.35-0.400.800.250.300.350.25-0.300.800.350.400.450.35-0.400.800.450.500.550.40-0.501.000.550.600.650.50-0.601.270.700.750.800.60-0.701.500.700.750.800.60-0.70″″()-4-PCB6()″7°(,)()µ″()µ(µ)µµµ″8-5-PCB9µ(µ″)µ10sldermask)″″″(″)()()-6-PCB33123I/OIC4IMP809IMP706IMP813X25043X2504556ICIC-●10100uF100uF●0.01uF410110uF500kHz20MHz1Ω0.5uA●ROMRAMVccGND●PCBPCBPCBPCB/ICPCBPCBd20001PCBEMC···CAD··PCB·//PCB-7-PCBPCBS-VCCS-VEEVEE-VCC1MOSIOL=IOH,TTLIOLIOH./ZO(Ω)10ECL50TTL100HC(T)2001ZOZO11IC2IC32Cdec..0.50.61µH/m0.4-0.5µH/m.4050PCB11TTLVccSVEES1.5mm/ICICdi/dtIC25I=c·dV/dt2Cdec.4PCBPCBIC100-100Pf,LF-IC[1/(π.τr)],τrICVEEVCCICLtrace-8-PCB1MHzQ2VccIC1MHz21MHz*1µHzZ1=6.28ΩRs=3.14ΩQ2Rp=12.56ΩZ0ICZ0=Ltrace/Cdecoupling1µHIC325Ltrace.2IC313ICLchoke+Cdec.τr3ns350mm50hH50pF3.2nsICICIC3EDILSOEMPCB3=1/π.τr=1/π.τrI(f)=2.I.τr/TI=T=τrτH5=PCBn30MHz60300µmPCBDILPCBPCBPCBPCB10kHz10kHz1MHz80-9-PCB10Nh/m1MHz//-10-