www.德州仪器.com
b0058-01
PECL
输入
vcxo_在
vcxo_在
P 分隔物
÷ 3
÷ 4
÷ 6
/8
÷ 8
÷ 16
÷ 1
÷ 2
÷ 4
÷ 8
9
0
o
9
0
o
p16-div
t0065-01
涉及 时钟
vcxo 时钟
y-输出 div4
y-输出 div4
(90 deg 变换)
y-输出 div8
(90 deg 变换)
90 deg
90 deg
y-输出 div8
90 deg
90 deg
lvcmos 输出
LVPECL 输出
CDCM7005
SCAS793A–JUNE2005–REVISEDJUNE2005
thelvpecloutputsaredesignedtoterminateintoa50-
Ω
loadtoV
CC
–2v.thelvcmosoutputssupports
thestandardlvcmosload(看Figure12).thelvpeclandlvcmosoutputscanbeenabled(正常的
运作)ordisabled(3-状态).
inaddition,theoutputphasecanbeshiftedby90degreeswhenusingtheadditionaldiv-用-4ordiv-用-8mode
ofthep16-div(看Figure20).inthedefaultmode(afterpowerup),thediv-用-16modeofthep16-divisactive.
tochangeittoa90degreephaseshift,bit30orbit31ofword1hastobeprogrammedaccordingly.thep
16-divhastobeselectedviathededicatedyxmuxtoobtainthe90degreephaseshift.theoutputsare
switchedinpairs.whenselectingthe90degreephaseshiftmode,thediv-用-16functionswillnolongerbe
有.the90degreephaseshiftedsignalislaggingtothenon-shiftedsignal.
figure20.90degreephaseshiftoptionofp-分隔物
thefollowingdiagramshowsthelvcmosandlvpecloutputsignalwhen90degreephaseshiftison.
figure21.outputswitchingdiagram
inaddition,thelvcmossupportsdisabled-至-lowand180degreeoutputphaseshiftforeachoutputindividually.
whenselectingthe180degreephaseshifttogetherwiththe90degreephaseshift,therespectiveoutputshasa
totalphaseshiftof270degree(看Table2).
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