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LoadCircuits
推荐 电阻 values:
为 5 v nom 供应, r
T
= 200
Ω
, r
S
= 90
Ω
为 3.3 v nom 供应, r
T
= 100
Ω
, r
S
= 30
Ω
R
T
/2
Transmission 线条
输出
输入
R
S
R
T
/2
推荐 电阻 values:
为 5 v 和 3.3 v nom 供应, r
T
= 100
Ω
,
V
T
= v
CC
- 2.55 v
R
T
/2
Transmission 线条
输出
输入
V
T
R
T
/2
_
+
输入
R
T
= 100
输出
R
S
R
S
Transmission 线条
推荐 电阻 values:
为 5-v 名义上的 供应, r
S
= 200
为 3.3-v 名义上的 供应, r
S
= 75
tb5d1m,tb5d2h
SLLS579B–SEPTEMBER2003–REVISEDMAY2004
ThetestloadcircuitsshowninFigure3andFigure4
arebasedonarecommended
pi
typeofloadcircuit
showninfigure15.the100-
Ω
differentialload
resistorR
T
atthereceiverprovidepropertermination
fortheinterconnectingtransmissionline,assumingit
hasa100-
Ω
characteristicimpedance.thetwo
resistorsR
S
togroundatthedriverendofthe
figure16.arecommended
Y
LoadCircuit
transmissionlinelinkprovidedccurrentpathsforthe
emitterfolloweroutputtransistors.thetworesistors
anadditionalloadcircuit,similartoonecommonly
togroundnormallyshouldnotbeplacedatthe
usedwitheclandpecl,isshowninfigure17.
receiverend,astheyshunttheterminationresistor,
potentiallycreatinganimpedancemismatchwith
undesirablereflections.
figure17.arecommendedpecl-styleload
电路
figure15.arecommended
pi
LoadCircuit
Animportantfeatureofalloftheserecommended
loadcircuitsisthattheyensurethatbothofthe
anothercommonloadcircuit,一个
Y
加载,isshownin
emitterfolloweroutputtransistorsremainactive
figure16.thereceiver-endlineterminationofr
T
是
(conductingcurrent)atalltimes.whendeviatingfrom
providedbytheseriescombinationofthetwort/2
theserecommendedvalues,itisimportanttomake
电阻器,whilethedccurrentpathtogroundis
surethatthelow-sideoutputtransistordoesnotturn
providedbythesingleresistorR
S
.推荐
止.failuretodosoincreasesthet
skew2
andV
oc(pp)
值,asafunctionofthenominalsupplyvoltage
值,increasingthepotentialforelectromagnetic
范围,areindicatedinthefigure.
辐射.
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