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APPLICATIONINFORMATION
GENERALFUNCTION
REF
代号
0x1000
[V]
(1)
SERIALINTERFACE
SCLK
FS
DIN
SCLK
FS
F15F15XXE0 XE1E14E15D0D1D14D15X
DIN
F15F15XXE1 E0E14E15XD0D1D14D15X
DSP模式:
µ
c 模式:
TLV5608
TLV5610
TLV5629
SLAS268E–MAY2000–REVISEDMARCH2004
thetlv5610,tlv5608,andtlv5629are8-频道,12-位,单独的-supplydacs,basedonaresistorstring
architecture.theyconsistofaserialinterface,aspeedandpower-downcontrollogic,areferenceinputbuffer,一个
resistorstring,andarail-至-railoutputbuffer.
theoutputvoltage(fullscaledeterminedbyexternalreference)foreachchannelisgivenby:
whererefisthereferencevoltageandcodeisthedigitalinputvalue.theinputrangeis0x000to0xffffor
thetlv5610,0x000to0xffcforthetlv5608,and0x000to0xff0forthetlv5629.apower-在-resetinitially
putstheinternallatchestoadefinedstate(allbitszero).
AfallingedgeofFSstartsshiftingthedataonDINstartingwiththeMSBtotheinternalregisteronthefalling
edgesofsclk.after16bitshavebeentransferred,thecontentoftheshiftregisterismovedtooneofthedac
holdingregisters,dependingontheaddressbitswithinthedataword.alogic0ontheldacpinisrequiredto
transferthecontentofthedacholdingregistertothedaclatchandtoupdatethedacoutputs.ldacisan
asynchronousinput.itcanbeheldlowifasimultaneousupdateofalleightchannelsisnotneeded.
fordaisy-chaining,doutprovidesthedatasampledondinwithadelayof16clockcycles.
figure13.datasampledondin
differencebetweendspmode(模式=n.c.or0)andµc(模式=1)模式:
•
inµcmode,fsneedstobeheldlowuntilall16databitshavebeentransferred.iffsisdrivenhighbefore
the16thfallingclockedge,thedatatransferiscancelled.thedacisupdatedafterarisingedgeonfs.
•
indspmode,fsneedstostaylowfor20nsandcangohighbeforethe16thfallingclockedge.
•
indspmodethereneedstobeonefallingsclkedgebeforefsgoeslowtostartthewrite(din)循环.
thisextrafallingsclkedgehastohappenatleast5nsbeforefsgoeslow,t
su(ck-fs)
≥
5ns.
•
inµcmode,theextrafallingsclkedgeisnotnecessary.不管怎样,ifitdoeshappen,theextranegative
sclkedgeisnotallowedtooccurwithin10nsafterfsgoeshightofinishthewritecycle(t
su(fs-c17)
).
11