Lattice Semiconductor
145
Data Sheet
September, 2002
ORCA Series 4 FPGAs
Package Parasitics
TheelectricalperformanceofanICpackage,suchassignalqualityandnoisesensitivity,isdirectlyaffectedbythe
packageparasitics.Table74listseightparasiticsassociatedwiththeORCApackages.Theseparasiticsrepresent
thecontributionsofallcomponentsofapackage,whichincludethebondwires,allinternalpackagerouting,and
theexternalleads.
FourinductancesinnHarelisted:LSWandLSL,theself-inductanceofthelead;andLMWandLML,themutualinduc-
tancetothenearestneighborlead.Theseparametersareimportantindetermininggroundbouncenoiseand
inductivecrosstalknoise.ThreecapacitancesinpFarelisted:CM,themutualcapacitanceoftheleadtothenearest
neighborlead;andC1andC2,thetotalcapacitanceoftheleadtoallotherleads(allotherleadsareassumedtobe
grounded).Theseparametersareimportantindeterminingcapacitivecrosstalkandthecapacitiveloadingeffectof
thelead.Resistancevaluesareinm.
Theparasiticvaluesin
Table74areforthecircuitmodelofbondwireandpackageleadparasitics.Ifthemutual
capacitancevalueisnotusedinthedesigner’smodel,thenthevaluelistedasmutualcapacitanceshouldbeadded
toeachoftheC1andC2capacitors.
Table74.ORCASeries4PackageParasitics
5-3862(C)r2
Figure60.PackageParasitics
PackageType
LSW
LMW
RW
C1
C2
CM
LSL
LML
352-PinPBGA
5.00
2.00
220
1.50
7—12
3—6
416-PinPBGAM
3.52
0.80
235
0.40
1.00
0.25
1.5—5.0
0.5—1.3
680-PinPBGAM
3.80
1.30
250
0.50
1.00
0.30
2.8—5
0.5—1.5
PAD N
LSW
RW
CIRCUIT
BOARD PAD
CM
C1
LSW
RW
LSL
LMW
C2
C1
LML
C2
LSL
PAD N + 1