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Document 2589440
AN-282 ᆌᆩԴऻ 0/&5&$)/0-0(:8":t10#09t/03800%."44"$)64&554t ֑ᄣຕဣཥएԨᇱ ۆ႙%41֑ᄣຕဣཥ ํाڦఇຕገ࣑ࡗײภतڟଇ߲࠲॰߁ǖො้क़֑ᄣ ࢅଉࣅዂᆶ၌ናݴޗՐ୲ăକኄၵ߁ܔᇀDSPᆌᆩ ࠲ዘᄲă ۆ႙֑ᄣຕDSPဣཥස3.1๖ăሞํाኴႜఇຕ ገ࣑ኮമLjఇె႑ࡽཚࣷཚࡗగዖ႑ࡽۙۉୟLjኴႜ ٷݣĂປ३ई୳հీࠀڪăසࡕఇె႑ࡽڦઠᇸ࿒܈Ă უ૰Ăୁई૰LjሶႴᄲ๑ᆩߌدڦړഗLjံॽ ଉገࣅྺۉუईୁۉă ֑ᄣຕဣཥڦዷᄲᇮॲ 3.1 Rev. A | Page 1 of 21 www.BDTIC.com/ADI AN-282 ᆌᆩԴऻ ఇె႑ࡽڦො้क़֑ᄣ ఇె႑ࡽڦො้क़ࢅና֑ޗᄣ߁ڦස3.2๖ăჄ ఇెຕՂႷᅜො้ڦक़क़߰ts֑ᄣLj้क़क़߰ՂႷ ႐ስLjඓԍ֑ᄣຕీඓ௮ຎᇱ๔ఇె႑ࡽă၂ Lj֑ᄣሁ֑)ܠᄣ୲ሁ*Ljఇె႑ࡽڦຕጴ๖৽ሁ ඓăසࡕ֑ᄣডณ)֑ᄣ୲ড*Ljሶณڟగᅃ้ۅLj ఇె႑ࡽ࠲ڦ॰႑တॽᅺڥփ֑ڟᄣܸ۪฿ăኄ๑் ᅜ࠲ڥᇀలઊຯ༬ጚሶרڦຎLjස3.3๖ă ຯ༬ټዐăໜጣ֑ᄣ୲ᅃօইگLjժఇెೕ ୲fa൵ৎᇀ֑ᄣೕ୲fsLjं۠႑ࡽሞೕዐॽ൵ৎᇀDCă ं้۠ڦᇘၳᆌ ఇె႑ࡽڦො֑ᄣ 3.4 ฉຎ൧ܔڦᆌೕᇘ๖ස3.5๖ă൩ጀᅪLjᅜ֑ᄣ ୲fsܔఇె႑ࡽfaႜ֑ᄣ้Ljํाฉׂࣷิଇዖं۠ೕ୲ ݴׯǖfs+faࢅfs-faăฉं۠(fs+fa)ณࠓׯ࿚༶Ljᅺྺ࿋ ᇀలઊຯ༬ټኮྔăူं۠(ݴׯfs-fa)ሶփLjړ႑ ࡽࡗגలઊຯ༬ټfs/2้Lj৽ࣷᆅ݀࿚༶ă 3.2 లઊຯ༬ጚሶ ■ ■ ྺՆ௨႑တ۪฿Ljྺټfaڦఇె႑ࡽՂႷᅜ fs>2fa֑ڦᄣ୲ႜ֑ᄣă ं۠ڦೕᇘၳᆌ ැfs<2faLjሶఇె႑ࡽټዐॽ݀ิं۠၄ၡă 3.3 ྺକं้۠ܔᇘࢅೕᇘڦᆖၚLjံ൩୯3.4๖ ڦᅃ߲֑ᄣኟ၀հ႑ࡽ้ڦᇘ๖຺ڦዖ൧ăڼᅃዖ൧ ዐ֑ڦᄣຕଉ၂؊ፁڦLjᅜԍାኟ၀հڦ႑ တăܾڼዖ൧ዐLj߲ዜኻ֑णକ຺߲ᄣԨLjධፁ ᅜԍାኟ၀հڦ႑တăڼෙዖ൧๖fs=2faኄዖఇࢵڦ ट၌ཉॲăසࡕ֑ᄣۅᇑኟ၀հኮक़࠲ڦဣၹۙփړLjڞ ዂߑࡻሞଭሁܔتኟ၀հႜ֑ᄣ(ܸփዐ๖ރڦ ኵ)تLjሶ۪ࣷ฿࠲ᇀኟ၀հڦᆶ႑တă຺ڼዖ൧ ๖fs<2faኄዖ൧LjٗᄣԨइڦڥ႑တ၂๖ኟ၀հڦೕ ୲گᇀf s /2Ljनྔټ႑ࡽं۠ڟDCᇑf s /2ኮक़ڦలઊ 3.5 Rev. A | Page 2 of 21 www.BDTIC.com/ADI AN-282 ᆌᆩԴऻ ᆯᅜฉڦ༪ஃኪLjADCኮമՂႷݣዃੇं۠୳հഗLj ሞfs/2तᅜฉೕ୲ՂႷᆶፁࠕڦፆټປ३LjᅜݞኹփႴᄲڦ ۠ंాټăं۠ᄺీᇸጲփሞలઊຯ༬ྷݔټኮాڦ एԨ႑ࡽڦၿհLjईኁᇸጲADCڦ܋࿄୳հټሯ ำă ं֑۠ܔᄣຕဣཥۯༀڦྷݔᆖၚස3.6๖ăฉ၂ ๖లઊຯ༬ೕ୲ڦۅႴጒༀLjഄዐं۠ݴׯᇑ႑ࡽ ၎ᇀႴۯༀྷݔᅜူڦᅃۅăူ၂๖ডߛೕ୲ۯༀ ྷݔݴׯ۠ंڟ၌ڦጒăኄዖጒॽڞዂডߛೕ୲ ้ڦኝ༹႑ሯԲইگLjܸं۠ྔټ႑ࡽᅼईၿհీࣷ ᆅഐ฿ኈLjස3.7๖ă ੇं۠୳հഗڦስ ၄ሞ்ᆌൣؤLjܔᇀߴۨఇెټfaLjੇं۠୳ հഗڦᄲ൱փৈᇑ֑ᄣ୲fs၎࠲LjܸᇑႴڦဣཥۯ ༀྷݔ၎࠲ăۯༀྷݔLj०ჾኮኸᇨፌٷ႑ࡽᇑ ՂႷဆڦፌၭ႑ࡽڦԲኵLjཚᆩdB๖ă்ړമ࠲ ႐ڦं۠ۯܔༀڦྷݔ၌ăADCଉࣅሯำतഄݥ၍ Ⴀᅺ໎ڦ၌ၳᆌॽሞฎࢫ༪ஃăူ௬ڦঢ়ᄓ݆ሶܔᇀ୳ հഗڦስీࡗᇀჹ߭LjڍഄᇱᆶၳڦLjժۙ ኝᅜࢇํाڦဣཥᄲ൱ă ੇं۠୳հഗڦᄲ൱ ं۠ۯܔༀڦྷݔೕᇘၳᆌ 3.8 ံLjยዃੇं۠୳հഗڦገችೕ୲ڪᇀႴڦఇె ټfaLjኄ৽ۨᅭକ୳հഗڦཚټfpass=faăۨᅭ୳հഗፆټ ڦഐ๔ೕ୲fstop=fs/2ăସ୳հഗፆټປ३ڪᇀႴڦডߛೕ ୲ۯༀྷݔDRLjᆩdB๖ăኄၵ֖ຕۨᅭ୳հഗ܉ࡗڦ ټ༬ኙLjनՂႷሞlog2(fstop/fpass)Ԡೕײฉํ၄ᇑۯༀྷݔ ၎ڦڪፆټປ३ăࢫՍඓۨྺํ၄ࡗټ܉ၽ୲Ⴔ ୳ڦհഗৎຼຕM(टۅຕ)Ljᅺྺ୳հഗࡐইሀྺԠ ೕײ6M dBă3.9၂๖କᅃ߲०ऺڦڇ໙๖૩Ljഄዐ႑ࡽ ټfaྺ3 kHzLj֑ᄣ୲fsྺ12 kHzLjᄲ൱60 dBۯڦༀݔ ྷăऺ໙LjႴᄲᅃ߲10ट୳ۅհഗă൩ጀᅪLjሞํ७ ዐLjยऺ8टۅᅜฉڦఇె୳հഗݥઓవLjยऺ12टۅ ᅜฉ୳ڦհഗሶबࢭփీࠀׯLjݥأঢ়ᄓ୳ڦݿհ ഗยऺටᇵăڟణമྺኹLjช࿄୯୳հഗڦ၎࿋༬ኙᅜ तྔټࢅాټ࿖հᄲ൱ăසࡕेฉኄၵ֖ຕLjੇं۠୳հ ഗڦยऺ߾ፕॽସටྭܸิ࿇ă 3.6 ं۠ᆅഐ߅ڦඡ႑ࡽᅼ 3.7 Rev. A | Page 3 of 21 www.BDTIC.com/ADI AN-282 ᆌᆩԴऻ ੇं۠୳հഗ๖૩ ࡗ֑ᄣᇑ؏ൽ 3.9 ฉຎᆩᇀඓۨੇं۠୳հഗްሗڦ܈ঢ়ᄓ݆ሶ्ยଉײ ႑ࡽᅜ၄ሞలઊຯ༬ೕ୲ᅜฉڦᆶೕ୲ăํा ൧ཚժݥසُLjܸሞೕ୲ডߛ้Ljتڦ႑ ࡽࣷᆶᅃၵጲປ३ă૩සLjሞฉ૩ዐLjසࡕలઊຯ༬ೕ ୲तᅜฉೕ୲ڦ႑ࡽᅙঢ়ປ३କ12 dBLjሶሞ6 kHzڦలઊ ຯ༬ೕ୲้ৈႴᄲ48 dB୳ڦհഗፆټປ३ăኄຫLjৈႴ ᄲᅃ߲8ट୳ۅհഗă3.10၂๖କኄᅃ൧ă ྔټປ३୳۠ंੇܔհഗڦᆖၚ ኟසമ௬༪ஃڦLjܔ႑ࡽႜࡗ֑ᄣڦዷᄲࡻت ᅜ०ࣅੇं۠୳հഗڦᄲ൱ăړLjࡗ֑ᄣᄺᆶփ૧ڦ ᅃ௬Ljन༵ࣷߛADCຕ୲LjDSPՂႷీࠕ߶ฉ ୲LjᅜՍྼ้֡ํፕăසࡕຕႷᅜزႜႚ๕د Ljሶॽᆩ߸ܠೕጨᇸăᅃዖᆶဌᆅ૰ݛپ༺ڦӄ ཞ้ሏᆩఇె୳հࢅຕጴ୳հरຍĂࡗ֑ᄣᅜतᅃዖ ྺ“؏ൽ”تڦࡗײă3.11๖ྺدཥ൧ႚLjഄዐᆶ ੇं۠߾ፕۼᆯADCኮമڦఇె୳հഗڅă3.12 ሶ փ ཞ Lj ࡗ ֑ ᄣ Բ K) Kྺ ኝ ຕ * ॽ ల ઊ ຯ ༬ ೕ ୲ ༵ ߛ Kfs/2Ljܸٗইگఇె୳հഗࡐڦইᄲ൱ăADCኮࢫ ڦຕጴ୳հഗ)ڼ7বॽၘဦ༪ஃຕጴ୳հ*ߵfsํႜੇं ۠ࠀీLjժሞfs/2้ᆶፁࠕڦፆټປ३Ljᅜํ၄Ⴔڦ ۯༀྷݔăሞࢫ௬ڦჺ༪ࣷዐ்ॽକڟLjਏᆶপኹ ༬ኙࢅଆࡻ၎࿋ၚᆌڦຕጴ୳հഗᇺԲ၎ᆌڦఇె୳հഗ ඹᅟํ၄)्ยDSP܈ፁࠕ*ăᆶ၌ஞ؋ၚᆌ(FIR)୳հ ഗᅜยऺׯਏᆶ၍Ⴀ၎࿋༬ኙăᆯᇀຕጴੇं۠୳հഗ ᅙॽټইfs/2Ljᅺُຕጴ୳հഗ༵ࠃڦຕํाฉࡤᆶ රᇆ႑တLjுᆶՂᄲֱੂ߲ᄣԨă๚ํฉLjK߲ᄣԨ ኻႴᄲֱੂᅃ߲ᄣԨăኄᅃࡗ؏“ྺײൽ”Ljॽሞ࠲ᇀ Σ-Δ႙ገ࣑ഗڦჺ༪ࣷևڼ)ݴ6ব*ዐᇎᅜၘဦ༪ஃăُ ྔLjํा؏ڦൽ߾ፕᅜᆯFIR୳հഗԨวཚࡗऺ໙K߲ ᄣԨڦᅃ߲ᄣԨઠኴႜăኄዖࡗ֑ᄣᇑ؏ൽᇱ ํाDSPڦፌዘᄲᇱኮᅃă ֑ᆩఇెگཚ୳հഗႜలઊຯ༬֑ᄣ 3.10 ᆯᅜฉ༪ஃኪLjཚࡗ༵ߛ֑ᄣ୲(֑ࡗ“ྺᄣ”)Lj ᅜই୳۠ंੇܔگհഗڦᄲ൱ăሞࢫ௬ڦჺ༪ࣷዐ்ॽ ੂڟLjᆶᅃૌ༬ڦADCࢅDACLjྺΣ-Δ႙ገ࣑ഗLj ்Ԩว৽ࡗ֑ᄣገ࣑ഗLjᅜटںٷই୳۠ंੇگհഗ ްڦሗ܈ă Rev. A | Page 4 of 21 www.BDTIC.com/ADI 3.11 AN-282 ᆌᆩԴऻ FDM႑ࡽגڦలઊຯ༬ೕ୲֑ᄣ ֑ᆩఇెࢅຕጴ୳հႜࡗ֑ᄣ 3.13 3.12 വ֑ᄣतഄᆌᆩ ሞԨবዐ்ॽକڟLjᆶၵDSPᆌᆩྜඇᅜথं ۠Ljժీᆶၳेںᅜ૧ᆩăړᆯADCႜຕጴࣅتڦఇ ె႑ࡽࡗגfs/2้Ljኄዖጒԥג“ྺలઊຯ༬ೕ୲”ई “വ֑ᄣ”ăలઊຯ༬ጚሶLjྺԍା႑တLjႜຕጴࣅ تڦ႑ࡽํݥ)ټڦाೕ୲*փᆌࡗגfs/2ăਉ૩ઠຫLj ୯ᅃዖۉ႑دܠୟްᆩഗᆌᆩLjഄዐೕܠݴୟްᆩ (FDM)ຕᆩ60 kHz108 kHzټڦLjᅜ112 kHzڦೕ୲ ܔഄႜ֑ᄣă3.13၂๖କ႑ࡽڦೕᅜतं۠ݴׯ ڦ࿋ዃăሞဣཥڦথ܋LjዘࠓDACኮࢫ୳ڦհഗྺټཚ ୳հഗLjܸփگཚ୳հഗLjՂႷ୳أ4 kHz52 kHzྷݔ ᅜాݴׯ۠ंڦLjᅜत࿋ᇀ֑ᄣೕ୲112 kHzݴׯڦă גలઊຯ༬ೕ୲֡ፕڦଷᅃዖᆌᆩዐೕ႑ࡽएڦټ থገ࣑ăሞ֑ᆩADCࢅDSPܠٷڦຕدཥཚ႑ࢅૃٳথ ऐᆩڦဣཥዐLjઠጲথऐമڦ܋ዐೕ(IF)႑ࡽᆯंೕ ഗࢅگཚ୳հഗူՎೕईۙྺएټ႑ࡽLjස3.14 ๖ăፌዕዐೕप๑ᆩᅃ߲ᇑ႑ࡽሜհೕ୲၎࿋ᅃዂڦԨ ናăंೕഗԈࡤᅃ߲एټ႑ࡽLjᇑଇୟኮक़ڦ ၎࿋ֶׯԲ૩ăंೕഗኮࢫگཚ୳հഗĂٷݣഗࢅ ADCăۆ႙ंೕഗڦገ࣑ࡼሞ4 dB6 dBኮक़ăړ႑ሯ Բ၌ᇀമ้܋Ljඁंأೕഗॽᅜ߀থऐڦኝ༹ሯ ำဣຕă ఇెူՎೕईۙ 3.14 සࡕᅜᇑԨናೕ୲၎ڦڪ୲ܔዐೕ႑ࡽႜ֑ᄣLjሶ ᅜඁंأೕഗ(ස3.15๖)ă၄ሞLjADCഐڟۙഗڦ ፕᆩăසࡕADC֑ڦᄣೕ୲ᇑఇె႑ࡽڦೕ୲၎ཞLjຕጴ ࣅྺॽᅃ߲DCኵăఇె႑ࡽᇑ֑ᄣೕ୲ڦඪࢆೋֶ ੂഐઠۼၟಆೕDfLjᆯُՍྜׯۙࡗײă Rev. A | Page 5 of 21 www.BDTIC.com/ADI AN-282 ᆌᆩԴऻ ADCࢅDACݴڦՐ୲तۯༀྷݔ থዐೕገຕጴူՎೕईۙ 3.15 ઠጲADCڦຕՂႷᆯDSP๑ᆩFFTتLjऺ໙ຕጴࣅ႑ ࡽํڦևࢅႵևăྺକԍାۙ႑ࡽዐԈࡤڦ၎࿋႑တLj ኄዖتՂᄲڦă ၂ܸᅟ९LjړADCሞגలઊຯ༬ೕ୲࣍ৣዐ߾ፕ้LjՂႷ ኪڢገ࣑ഗኍܔలઊຯ༬ೕ୲ᅜฉڦೕ୲ۯڦༀႠ ీăೕ୲ডߛ้LjADCڦ႑ሯԲࢅၿհ฿ኈႠీཚ ࣷইگLjᅺُኍܔႴೕ୲ڦୁႠీՂႷፁᅜፁ ဣཥႴ൱ăגలઊຯ༬ೕ୲֡ፕཚᄲ൱ߛܔೕ႑ࡽ ߸ྺԀڦADCLjܸփኻీᆩᇀگᇀలઊຯ༬ೕ୲ڦᆌ ᆩڦADCă ଉࣅዂᆶ၌ናݴޗՐ୲ڦᆖၚ ֑ᄣຕဣཥႴᄲ୯ܾڼڦዖዷᄲᆖၚఇຕईຕఇገ ࣑ࡗڞײዂڦᆶ၌ናݴޗՐ୲ڦᆖၚă༪ஃዐLj்ॽ ADC)ईDAC*ڦ࿋ຕྺገ࣑ഗݴڦՐ୲NăܔᇀADCLj ྺݴྷݔ2N߲ොपLj߳पᆯᅃ߲N࿋ܾጴ๖ă ܔᇀDACLjᆯN࿋ܾጴፇׯLjᆶ2N߲ీڦ ොपă3.16၂๖࿋ຕNĂܔᆌڦपຕ2Nᅜतፌگᆶၳ࿋ (LSB)ڦዘLjዘᆩଇዖݛ๕๖ǖᅃྺӥݴԲLjᅃྺᆩ dB [20 log10(2N)]ई6.02N dB๖ڦԲ୲ăُԲኵ)๖ྺӥ ݴԲईdB*پገ࣑ഗۯڦༀྷݔLjनፌٷဆ႑ࡽᇑ ፌၭဆ႑ࡽڦԲኵăኄՂႷኸLj3.16ዐۯڦༀ ྷݔኵ๖ၙADCࢅDACۯڦༀྷݔኵLjܸுᆶ୯ၿ հࢅۙ฿ኈڪୁႠీ၌ăኄၵኵᄺփپ႑ࡽᇑଉ ࣅሯำڦஃԲኵăᆶ࠲ኄၵࣆ༶Lj்ॽሞฎࢫምፕ༪ ஃă ࿋ຕN पຕ2N %, 100/2N dB, 6N 8 256 0.4 48 10 1024 0.1 60 12 4096 0.025 72 14 16384 0.006 84 16 65536 0.0015 96 18 262144 0.0004 108 20 1048576 0.0001 120 22 4194304 0.000025 132 24 16777216 0.000006 144 3.16 ଉࣅஃĂ႑ሯԲतᆶၳ࿋ ADCࢅDACڦᆶ၌ݴՐ୲ڞዂ႑ሯԲ(SNR)ᆶᅃ߲ஃ၌ ኵLj࿋ຕNࡧڦຕăྺକႜᆶᅪᅭ֪ڦଉLjᆩฎگ ᇀገ࣑ഗ၌ڦྷݔޗଉײኟ၀հघADCăኄࣷڞ ዂᄣԨᇑᄣԨक़ڦဃֶLjׂܸٗิଉࣅሯำăኄᅜᆩຕ ბ݆ݛຫǖሞలઊຯ༬ڦڥ֪ాྷݔټଉࣅዂݛ ߵሯำۉუᅜᆩ்ຄဒࠅڦ๕q/√12๖Ljഄዐqྺገ ࣑ഗፌگᆶၳ࿋(LSB)ڦዘăLSBڦኵqऺڦ໙݆ݛॽ ADCईDACڦଉأྷݔײᅜ2Năሞுᆶဃֶᇸڦၙገ ࣑ഗዐLjஃฉڦߵݛଉࣅሯำۉუᄺᇑ႑ࡽናޗ ࢅೕ୲࠲ă࠲ᇀኄᅃ०ࠅڇ๕ײࡗڞླྀڦLj൩֖ᅜူ ࿔၅ǖ W.R. Bennett, Spectra of Quantized Signals, BSTJ 27, pp. 446-472, July 1948 ܔᇀଉײኟ၀հLjᅜᅃօڥኪLjஃฉڦݛ ߵ႑ࡽᇑଉࣅሯำԲऺڦ໙ࠅ๕ྺǖ SNR = 6.02N + 1.76dB. Rev. A | Page 6 of 21 www.BDTIC.com/ADI AN-282 ᆌᆩԴऻ ADCۯༀ֪ ଉࣅሯำएԨኪ๎ లઊຯ༬ټfs/2ڦాྷݔߵݛଉࣅሯำǖ లઊຯ༬ڦాྷݔټଉײኟ၀հߵݛ႑ࡽ ᇑߵݛሯำԲǖ ᆶၳ࿋ຕ(ENOB)ǖ 3.18 12࿋Ă200 kSPS ADC AD678ڦ2048ۅFFT 3.17 ᆌጀᅪLjߵݛଉࣅሯำᅃӯৎຼڪᇀలઊຯ༬ྷݔټ ాټڦሯำăڍLjኄᅃࡀሶሞగၵཉॲူփׯ૬ăස ࡕଉࣅဃֶ႑ࡽᇑႜຕጴࣅتڦ႑ࡽኮक़٪ሞ၎࠲࠲ ဣLjሶଉࣅሯำీणዐሞ႑ࡽڦၿհฉLjܸփ ሌݴොᇀኝ߲ాྷݔټăړ႑ࡽྺኟ၀հྺ֑ᄣ ೕ୲ݴڦೕၿհ้Ljटᆶీ݀ิฉຎ൧ă ֪ADC้Ljཚॽᅃ߲كኟ၀հ႑ࡽแेᇀADCڦ ܋Ljժ૧ᆩDSPरຍऺ໙SNRLjස3.18๖ăޱᄾ Վ࣑(FFT)تᆶ၌ຕଉ้ڦक़ᄣԨLjժॽഄገ࣑ڟೕ ዐLj૩ස3.19ኍܔ12࿋200 kSPS֑ᄣADC AD678๖ڦ ೕăࢫLjᆩೕऺ໙SNRࢅएԨ႑ࡽڦၿհLjኄ ᇑఇెೕݴဆᅏݥ၎ຼăံऺ໙႑ࡽڦߵݛኵLj ࢫऺ໙లઊຯ༬ాྷݔټᆶഄೕ୲)ݴׯኄփৈԈ ࡤሯำLjܸԈࡤ฿ኈׂ*ڦߵݛኵăኄଇ߲ଉڦԲኵ ᆩdB๖नྺ႑ሯԲ(SNR)ăADC߳ڦዖሯำᇸLjԈઔओ ݥݴྲࢅݴ၍ႠĂ฿ஓᅜतADCాևሯำᇸLjڞዂ֪ڦڥ SNRگᇀஃኵ6.02N+1.67dBăُྔLjኄၵဃֶཚ უӦ୲ࡧڦຕLjᅺُࣷໜጣೕ୲ܸߛ༵ڦሺٷăऺ ໙ሯำڦߵݛኵ้Ljသ࠹ฉᄲԈઔएԨ႑ࡽڦၿհăᆶ ้ࢪॽኄᅃ֖ຕྺ႑ࡽᇑሯำे฿ኈԲS/(N+D)Ljڍཚ ० ྺ ں ڇ႑ ሯ Բ SNRă ֑ ᄣ ADC) 12࿋ Ă 200 kSPS*AD678ڦS/(N+D)ۆڦ႙൸၍ස3.20๖ă 3.19 SNRڦଷᅃዖ݆ݛ๑ᆩᆶၳ࿋ຕईENOBăᆶၳ࿋ ऺ໙݆ݛ૧ᆩ֪ڦڥSNRኵLj൱SNRࠅ๕ዐڦN)֖९ 3.17*ă૩සLjၙڦ12࿋ADCਏᆶ74 dBڦஃSNRኵLj ܔᆌᇀ12߲ᆶၳ࿋ăසࡕ֪ڦڥSNRྺ68 dBLjሶܔᆌᇀ 11߲ᆶၳ࿋ăኄຫLjํाڦ12࿋ADCڦႠీᇑၙڦ11 ࿋ADCڦႠీ၎ړă3.20ᄺሞSNR൸၍ฉ၂๖କAD678 ڦENOBႠీă൩ጀᅪLjሞگೕ้LjAD678ڦᆶၳ࿋ຕג ࡗ11.4ă ᄺᅜ૧ᆩኟ၀հ൸၍ెࢇऺ݆ݛ໙ᆶၳ࿋ຕă֑ᆩኄዖ ้݆ݛLjႴॽᅃ߲ኟ၀հแेᇀADCLjժ֑णැ߅ᄣԨă Rev. A | Page 7 of 21 www.BDTIC.com/ADI AN-282 ᆌᆩԴऻ 12࿋Ă200 kSPS ADC AD678ڦS/(N+D)ࢅᆶၳ࿋ຕ ߵ႑ࡽۯༀྷݔስADCݴՐ୲ ኍۨߴܔᆌᆩስڦړADCᇺփኹഡภڟඓۨႴ࿋ ຕࢅ֑ᄣ୲Lj࣏ՂႷߵتڦఇె႑ࡽִADCڦ ୁࢅୁ༬ႠLjቴڟڦړದă၂Ljኄᅃࡗײփ Ն௨ࣷںภतڟႠీᇑׯԨڦ࢚ă DSPᆌᆩࢅۯༀྷݔᄲ൱ 3.20 ኄዖ݆ݛփ้ܔक़ᄣԨኴႜFFTLjܸऺ໙ຕڦۅፌ ॅెࢇኟ၀հăስኟ၀հናޗĂೋᅎĂೕ୲ࢅ၎࿋ڦᇱ ሶᄲ๑ํाኟ၀հຕۅᇑஃኟ၀հኮक़ڦߵݛဃ ֶፌၭăཞᄣLjၙADCڦஃߵݛဃֶྺq/ ă૧ᆩ 3.21๖ࠅ๕Ljऺ໙ํाኟ၀հᇑஃኟ၀հኮक़ڦݛ ߵဃֶᅜतᆶၳ࿋ຕă๑ᆩኟ၀հ൸၍ెࢇڦڥ֪݆ݛ ENOBᇑ๑ᆩSNRरຍइڦڥENOBኮक़ਏᆶଆࡻڦ၎࠲ ႠăසࡕSNRऺ໙ᆩڦ႑ࡽၭᇀଉײLjሶྺ๑ኄଇዖ ݆ݛ၎࠲LjՂႷሺेᅃ߲ၯኟဣຕLjසူ๖ă ๑ᆩኟ၀հ൸၍ెࢇऺ݆ݛ໙ENOB QA = ᆯెࢇኟ၀հํڦڟڥाߵݛဃֶ QT = ᆯፌॅెࢇኟ၀հڦڟڥஃN࿋ߵݛ ဃֶ= ᇑSNR၎࠲ǖ SNR = 3.22 3.22၂๖କႹܠࢇDSPتڦᆌᆩLjժߴକܔᆌ႑ ࡽڦৎຼۯࢅټༀྷݔăۯༀํྷݔाฉᆶଇݛ௬ǖ ୁࢅୁăୁۯༀܔྷݔᆌᇀ3.22ዐ༵ࠃڦኵ)ࢮ ADCৢༀဃֶ*ăୁۯༀྷݔሶᇑADCڦၿհ฿ኈႠీ ၎࠲ă૩සLjሞຕጴೕݴဆᆌᆩዐLjଉײኟ၀հ ႑ࡽڦၿհࣷ၌ဣཥሞٷ႑ࡽ٪ሞڦ൧ူဆၭ႑ࡽ ీڦ૰ăୁ၍Ⴀཚᆩၿհ฿ኈईጺၿհ฿ኈ(THD) ๖ăܔᇀํाڦADCLj࿋ຕీժփీࡻںኸ๖ገ࣑ഗ ڦၿհ฿ኈႠీăୁۯༀگྷݔᇀSNRࠅ๕ᇨ֪ۯڦ ༀྷݔ6.02N + 1.76dBăᆯᇀኄၵᇱᅺLjຕ֩ՂႷԈࡤ ୁࢅୁ༬ႠLjᅜՍᆩࢽߵᆌᆩፔڦስă SNRํा-1.76DB+گഥଉڦײ႑ࡽೝ 6.02 3.21 Rev. A | Page 8 of 21 www.BDTIC.com/ADI AN-282 ᆌᆩԴऻ ADCৢༀڿد༬Ⴀ ݥၙ3࿋ADCࡧڿدڦຕ ௮ຎADCৢༀႠీڦएԨ༬Ⴀස3.23๖ă ADCৢༀ༬Ⴀ Ŗ ྲݥݴ၍Ⴀ(DNL) Ŗ ओݥݴ၍Ⴀ(INL) Ŗ ฿ஓ Ŗ ሺᅮဃֶ Ŗ ೋᅎဃֶ 3.23 3.18 ሞᅃ߲3࿋ADCڦၙࡧڿدຕዐ)3.24*Ljఇె႑ࡽ ࿋ᇀೝዡLjຕጴ࿋ᇀؽዡăADCڦຕጴሞᅃ ۨڦ႑ࡽాྷݔᆶၳăܔᇀߴۨஓLjڦଉ ྺஓ܈ڦăၙྺ܈1 LSB)ፌگᆶၳ࿋*LjํڍाฉLj ߲ஓ܈ڦᇑഄ၎ତஓփཞăஓ܈ᇑၙڦ1 LSBኵ ڦೋֶݥݴྲྺ၍ႠईDNLăᅃ߲ਏᆶܠዖփཞဃֶڦ 3࿋ADCࡧڿدڦຕස3.25๖ă൩ጀᅪLjஓ100ᅺྺ၎ ତஓڦDNLဃֶড۪ܸٷ฿ăሞԿ࣍ဣཥዐLj฿ஓీࣷ ׂิናࢅږӦۯLjᅺُ֖ຕܔᇀኄዖᆌᆩዐڦADCስ ݥዘᄲă 3.25 DACৢༀڿد༬Ⴀ ௮ຎDACৢༀڿد༬ႠڦएԨ༬Ⴀස3.26๖ă DACৢༀ༬Ⴀ ओݥݴ၍ႠईINLཚ၎ܔᇀஓዐ႐ઠ֪ଉăཚࡗۅ܋ ࣃᅃཉ၍Ljஓዐ႐ᇑၙ၍ڦፌٷೋֶनྺINLLj ස3.25๖ăᅃၵ൧ူLjओݥݴ၍Ⴀ၎ܔᇀፌॅెࢇ ၍ઠۨᅭLj၍ཚ૧ᆩፌၭܾ݆ױઠऺ໙ă ሺᅮࢅೋᅎဃֶںڪᆖၚᆶஓLjཚᆩԲডدཥڦर ຍٗဣཥዐᇎᅜၩأă Ŗ ྲݥݴ၍Ⴀ(DNL) Ŗ ओݥݴ၍Ⴀ(INL) Ŗ ۙڇݥႠ Ŗ ሺᅮဃֶ Ŗ ೋᅎဃֶ 3.26 ၙ3࿋ADCࡧڿدڦຕ ᅃ߲ၙ3࿋DACৢڦༀࡧڿدຕස3.27๖ăຕጴ ኵ࿋ᇀೝዡฉLjܔᆌڦఇెኵ࿋ᇀؽዡฉăᇑ ADCփཞLjDACփࣷᆶ฿ஓăኍܔ߲ຕጴஓLjࣷۼ ׂิᅃ߲ොڦఇెۉუăྲݥݴ၍Ⴀۨᅭྺ၎ତఇ ెኵኮक़ڦक़߰ᇑၙڦ1 LSBኵڦೋֶăࡗڦٷDNL ဃֶీڞዂۙڇݥႠጒLjස3.28๖ăසࡕຕጴஓ ߛ༵ڦᆅഐఇెኵڦইگLjሶණྺDACྺۙڇݥ Ⴀă၎ݒLjසࡕDACڿد༬Ⴀڦၽ୲ሞኝ߲ాྷݔਏᆶ၎ ཞࡽޙڦLjሶණྺDACྺۙڇႠăሞԿ࣍ဣཥዐLjۙڇݥ ႠጒׂࣷิናږLjᅺُኄᅃ༬ႠܔᇀኄዖᆌᆩዐڦDAC ስݥዘᄲă 3.24 Rev. A | Page 9 of 21 www.BDTIC.com/ADI AN-282 ᆌᆩԴऻ ሺᅮࢅೋᅎۨڦᅭᇑADC၎ຼLjժںڪᆖၚᆶఇె ኵă ၙ3࿋DACࡧڿدڦຕ ADCۯༀႠీ ྺକీᆩᇀܠٷຕDSPᆌᆩLjADCՂႷਏᆶথڦୁ ࢅୁ༬ႠăADCڦፌዘᄲۯༀ༬Ⴀଚස3.29๖ă ADCۯༀ༬Ⴀ 3.27 ݥၙ3࿋DACࡧڿدڦຕ !!!!!Ŗ! ႑ࡽᇑሯำे฿ኈԲ(S/N + D)तᆶၳ࿋ຕ !!!!!Ŗ ރኵሗොĂރኵၿհݴׯतሗොۯༀ(ྷݔSFDR) !!!!!Ŗ ጺၿհ฿ኈ(THD) !!!!!Ŗ ඇࠀ୲(ټFPBW) !!!!!Ŗ ඇ၍Ⴀټ !!!!!Ŗ ۙ฿ኈ(IMD) !!!!!Ŗ ০ჽ้क़ࢅ০۶ۯ !!!!!Ŗ ຨༀၚᆌ !!!!!Ŗ ࡗუ࣬ް 3.29 ฎࢫ்ॽੂڟLjᆶႹܠॐࠓࢇDSP ADCยऺLjٷևݴ ॐࠓۼᄲ൱ሞገ࣑ഗኮമݣዃᅃ߲֑ᄣԍٷݣഗ (SHA)Ljස3.30๖ăኵڥጀᅪڦ૩ྔFlash႙ገ࣑ഗࢅ Σ-Δ႙ገ࣑ഗLjࢫኁᆮྺዘᄲăྺइڥSHA-ADCྜڦܔኝ ۯༀႠీLjՂႷॽܾኁणׯሞཞᅃႊೌฉLjईኁณፕྺ ᅃ߲ྜኝڇీࠀڦᇮ༵ࠃăޏሶLjᆯ߲ڇഗॲڦ༬Ⴀඓۨ SHA-ADCፇࢇڦኝ༹ۯༀႠీबࢭփీڦăܔADC ྜڦኝୁࢅୁ༬Ⴀڦᄲ൱٣ิକాዃೌฉSHA֑ڦᄣ ADCăኄၵገ࣑ഗփ٪ሞSHAᇑADCথ੨ڦ࿚༶Ljժྺᆩ ࢽ༵ࠃକྜኝڦୁࢅୁ༬Ⴀă 3.28 ओݥݴ၍Ⴀۨᅭྺఇెኵ၎ܔᇀཚࡗۅ܋ࣃڦၙ ၍ڦፌٷೋֶăᇑADCᅃᄣLjINLᄺᅜ၎ܔᇀፌॅె ࢇ၍ઠۨᅭă Rev. A | Page 10 of 21 www.BDTIC.com/ADI AN-282 ᆌᆩԴऻ ރኵሗොĂރኵၿհݴׯतሗොۯༀྷݔ (SFDR) ాዃ֑ᄣԍڦీࠀADC ރኵሗොईރኵၿհݴׯ႑ࡽࢅDCኮྔፌڦٷೕ ݴׯăኵ๖ྺ၎ܔᇀଉײ႑ࡽڦߵݛኵڦ dBኵăރኵሗො༬Ⴀᆶ้ᄺྺሗොۯༀ(ྷݔSFDR)ă 3.32၂๖କAD678ރڦኵሗොႠీۆ႙൸၍ă AD678ރڦኵሗොၚᆌ(200 kSPSĂݥೝ2048 ۅFFT) 3.30 ႑ሯԲࢅᆶၳ࿋ຕ ኟසኮമ༪ஃڦLj႑ሯԲ༬Ⴀ߁ٷৃړᄽহᆩాڦ ࡥፌڦݿୁ༬Ⴀăॽၿհ฿ኈڦᆖၚԈࡤሞኄᅃ༬Ⴀ ዐࡀፔ݆Ljᅺُ(S/N+D)ۨᅭྺ֪ڦڥ႑ࡽڦ ߵݛኵᇑలઊຯ༬ೕ୲ᅜူڦᆶഄೕ)ݴׯԈઔၿ հLjڍփԈઔDC*ڦڦࢅߵݛԲኵă3.31၂๖କෙዖ ߛFlash႙ADC(ڦS/N+D)ۆ႙൸၍ăዐཞ้၂๖କ ݒୁۉઍ႙ሏ໙ٷݣഗAD9617ڦၿհ฿ኈႠీLjᅜࠃԲ ডăSNR֪ଉࡕᄺᅜᆩᆶၳ࿋ຕईENOB๖Lj3.31 ᄺ၂๖କኄᅃۅă ጺၿհ฿ኈ(THD)ኸമୃ߲ၿհڦݴׯࢅߵݛᇑଉײ ႑ࡽڦߵݛኵኮԲLjᆩӥݴԲईdB๖ăܔᇀߛᇀ లઊຯ༬ೕ୲ڦ႑ࡽईၿհLjᆩഄं۠ऺݴׯ໙ă 3.33၂๖କAD678ۆڦ႙THDႠీă FLASH႙ADCतሏ໙ٷݣഗۯڦༀႠీ AD678ڦጺၿհ฿ኈĂඇࠀ୲ࢅټඇ၍Ⴀټ FLASH႙ADC AD9020 AD9060 AD9028/9038 AD9006/9016 ݴՐ୲ 10 BITS 10 BITS 8 BITS 6 BITS 3.32 ጺၿհ฿ኈ(THD) ֑ᄣ୲ 40 MSPS 60 MSPS 250 MSPS 400 MSPS 3.33 3.31 Rev. A | Page 11 of 21 www.BDTIC.com/ADI AN-282 ᆌᆩԴऻ ඇࠀ୲ټ ADCڦࠀ୲(ټFPBW)ኸኍܔଉײLjዘࠓ)๑ ᆩFFT*एԨೕ୲ڦናޗԲଉگײ3 dB้ڦೕ୲ăٗ 3.33ᅜੂLjAD678ڦࠀ୲ټሀྺ1 MHzăܸLj ྺ๑༬ႠᆶᅪᅭLjՂႷॽᇑSNRĂENOBࢅၿհ฿ኈ ࢇഐઠִLjܸٗඓۨADCሞFPBWೕ୲ڦኈኟۯༀݔ ྷă AD678ڦIMD൸၍DŽF1 = 9.08 kHZLjF2 = 9.58 kHzLj fs = 200 kSPSDž ඇ၍Ⴀټ ADCڦඇ၍Ⴀټኸڟٳ֑ᄣԍ(SHA)ڦუӦ୲ ้ڦೕ୲ăُ้Ljዘࠓኟ၀հڦናޗইگփڟ-0.1 dBăᅃُࡗגڋೕ୲Lj֑ᄣ႑ࡽڦ฿ኈॽ၂ዸሺٷă AD678 ADCᅙኍܔټႜᆫࣅLjᅜܔ၂ዸߛᇀገ ࣑ഗలઊຯ༬ೕ୲ڦ႑ࡽႜവ֑ᄣăAD678ڦඇ၍ Ⴀྺټ500 kHzLj3.33ᄺ၂๖କኄᅃۅă 3.35 ۙ฿ኈ(IMD) ړᆯଇዖೕ୲)F1ࢅF2*ڦኟ၀հፇ้ׯLjՍࣷ݀ิ ۙ฿ኈ(IMD)ăඪࢆਏᆶݥ၍Ⴀڦഗॲࣷۼሞࢅೕ୲ࢅֶೕ ୲mF1± nF2ׂ้ิ(m+n)฿ኈओLjഄዐmĂn = 0,1,2,3...ă ۙၜኸmईnփڪᇀ0ڦఫၵၜă૩සLjܾၜྺ(F1 + F2) ࢅ(F1 - F2)Ljෙၜྺ(2F1 + F2)Ă(2F1 - F2)Ă(F1 + 2F2)ࢅ (F1 - 2F2)DŽ֖९3.34DžăIMDओ๖ྺ֪ڦڥ႑ࡽ ڦࢅߵݛᇑ฿ኈၜڦࢅߵݛኮdBԲăแेᇀADCڦଇ ߲႑ࡽਏᆶ၎ཞڦናޗLjഄࢅރڦኵᇑଉײ၎ֶ-0.5 dBăIMDओࡃᅃࣅྺ0 dB႑ࡽă3.35၂๖କAD678ڦ ۆ႙IMD FFT൸၍ă ۙओ ᆩ݆ݛݛइڥୁ၍Ⴀ൸၍ ܔᇀኄዖ֪ଉLjႴॽᅃ߲ଉײኟ၀հแेᇀADCLjժ֑ णٷଉᄣԨă߲ஓڦ၄ْຕऻሞݛฉLjස 3.36ፑฉݛ൸၍๖ăܔᇀ12࿋ገ࣑ഗLjྺକइڥᆶཥऺ ᅪᅭڦࡕLjႴᄲ֑णຕӥྤᄣԨăݛᆌࢇޙኟ၀հ ڦၙ߁୲ݴ܈քLjස3.36ᆸฉݛ൸၍๖ăࢫLj ૧ᆩኟ၀հ߁୲ࡧ܈ຕࡃᅃࣅݛຕLjᅜइڥዐ ူݛ൸၍๖ڦDNLăओݥݴ၍ႠᅜཚࡗՊેओ ݛઠඓۨăેओݛዹڿدྺ܈ೝă3.37๖ྺ 12࿋Ă100kSPS ADC AD7870ᅜ100 kSPS୲ܔᅃ߲25 kHz ႑ࡽႜຕጴࣅت้Lj૧ᆩ݆ݛݛइڦڥୁ ၍Ⴀ൸၍ăዐுᆶ၄ডڦٷॖރLjਏᆶଆࡻֶڦ ݴ၍Ⴀ܈ăᆶ࠲ຕბऺ໙ၘڦဦ႑တLj൩֖AD7870ຕ ֩ă 3.34 Rev. A | Page 12 of 21 www.BDTIC.com/ADI AN-282 ᆌᆩԴऻ ᆶၳ০ჽ้क़֪ڦଉ ᆩऺݛ໙ୁ၍Ⴀ 3.38 3.36 AD7870ڦୁ၍Ⴀ12࿋Ă100 kSPS ADCLj25 kHz ০۶ۯ ০۶ۯኸᄣԨᇑᄣԨኮक़ሞํा֑ᄣڦᆶၳ้क़ۅฉڦ ֶᅴLjස3.39๖ăኄၵဃֶิׂڦᇱᅺᅃӯᆶܠዖă ሞํाڦADCዐLjঢ়ࣷᆶ߅ඡᇸ֑ܔᄣ้ዓႜ၎࿋ۙ ǗփଆքਆĂಖୟࢅথںरຍᆅഐټڦໜऐሯำĂۉ ᇸ၍ሯำईຕጴሯำۼీ߅ྺׯඡᇸăᆯُሰڦׯဃֶ ᅜᆩ้ߵݛक़۶ۯઠ๖ăߵݛ০۶ۯᆅഐڦ၎ ᆌۉߵݛუဃֶࣷইگADCڦኝ༹႑ሯԲăኟ၀հ ฉڦ၎࿋۶ۯᅜׂิᇑ֑ᄣ้ዓฉڦ۶ۯ၎ཞڦᆖၚă ০۶ڦۯᆖၚ 3.37 ০ჽ้क़(ईᆶၳ০ჽ้क़) ০ჽ้क़)ᆶ้ᄺྺ০้क़*ኸ֑ٗᄣ้ዓڦമᄂ ڟADCํा֑ᄣ้ڦक़ଉ)֖९3.38*ăኄᅃ༬Ⴀኮᅜ ዘᄲLjᅺྺᆶዺᇀᆩࢽኪڢ၎ܔᇀ႑ࡽ้ႾLjࢆ ้ᆌᆩ֑ᄣ้ዓăሞ߲ܠADCتۯༀ႑ࡽ้Ⴔᄲཞօ֑ ᄣईႴᄲԵُ߶ጷڦഄᆌᆩዐLjՂႷኪ߳ڢഗॲኮक़࠲ ᇀ֖ຕֶڦᅴईඹֶă 3.39 Rev. A | Page 13 of 21 www.BDTIC.com/ADI AN-282 ᆌᆩԴऻ 3.40၂๖କփཞ০۶ۯኵ้০۶ۯኄᅃ߲ڇᅺ໎ܔ SNRׂิڦᆖၚLjଉײኟ၀հೕ୲ࡧڦຕă࠲ ᇀSNRᇑ০۶࠲ڦۯဣײݛ๕ײࡗڞླྀڦLj൩֖࿔၅1ă ๑ᆩఇెܠୟްᆩഗدڦཥຕ֑णဣཥ ০۶ܔۯSNRڦᆖၚ 3.42 ࡗუ࣬ް้क़ ࡗუ࣬ް้क़ۨᅭྺٗࡗუ႑ࡽዘႎገ࣑ഗ้ྷݔਸ ๔ڟADCۨࡀڟٳ܈Ⴔ้ڦक़ଉLjස3.43๖ăኄ ᅃ༬ႠཚኍגܔADCྷݔ50%ڦ႑ࡽܸჾă ႴჾLjADCܔᇀגଉײ႑ࡽᆌഐڟၙ၌ޗഗڦፕᆩǗ ሞࡗუጒူLjADCᆌׂิኟଉײஓईଉײஓăᅃ ၵገ࣑ഗ༵ࣷࠃגଉࢅײവଉײՔኾLjᅜՍघऄሺᅮۙኝ ۉୟă 3.40 ADCࡗუ࣬ް้क़ ຨༀၚᆌईॺ૬้क़ ADCڦຨༀၚᆌ)ईॺ૬้क़*ኸሞแेଉײሂ ࢫLjADCॺ૬ۨܮ܈Ⴔ้ڦक़)֖९3.41*ăሞ ADC֑ᆩఇెܠୟްᆩഗൻڦۯᆌᆩዐLjස3.42๖Lj ኄᅃ༬Ⴀ࠲ዘᄲăܠୟްᆩഗᅜ๑ADCڦ݀ ิଉڦ܈ޗײཌՎăසࡕܠୟްᆩഗࢅADC࿄؊ॺݴ ૬Ⴔ܈Ljሶॽᆅഐୁཚڢᇑཚڢक़زඡă ADCຨༀၚᆌ 3.43 3.41 Rev. A | Page 14 of 21 www.BDTIC.com/ADI AN-282 ᆌᆩԴऻ DACॺ૬้क़հႚ DACۯༀႠీ ܠٷຕDSPᆌᆩፌዕۼᄲዘࠓۯༀఇె႑ࡽLjᅺُDACڦ ୁႠీᇑADCႠీᅃᄣዘᄲăDACڦዷᄲୁ༬Ⴀස 3.45๖ă DACۯༀ༬Ⴀ ■ ■ ■ ■ ■ ॺ૬้क़ றِஞ؋௬ओ ၿհ฿ኈ ႑ሯԲ ᅼೕጆᆩ༬Ⴀ 3.44 ॺ૬้क़ DACॺڦ૬้क़دཥฉۨᅭྺٗຕጴገ࣑(ཚٗ50% ۅਸ ๔ ֪ ଉ ) ڟDAC ॺ ૬ గ ᅃ ဃ ֶ ( ټཚ ྺ 1/2 LSBLjᅜፌዕኵྺዐ႐)ᅜా้ڦक़ăස3.45๖Ljॺ૬ ้क़ڦᅃևݴీᄲࡃᅺᇀਸ࠲دۨࠦڦჽăසࡕ DACᆶᅃፇ٪ഗईस٪ഗLjሶॺ૬้क़ᆌٗ٪ഗ ཚஞ؋ईस٪ഗ้ዓஞ؋ڦ50%ۅਸ๔֪ଉăDACଉ ॺײ૬้क़၎ܔᇀٗ000...0111...1ڦຕጴገ࣑ܸ ჾăDACዐଉॺײ૬้क़၎ܔᇀٗ011...1ڟ100...0ईٗ 100...0ڟ011...1ڦຕጴገ࣑ܸჾă 3.45 ၎ܔᇀDACۨᅭॺڦ૬้क़ ৈৈ၎ܔᇀLjۨᅭDACॺ૬้क़ᄺྜඇኟඓڦLjස 3.46๖ăُ้Ljॺ૬้क़ኸٗਸᅜ؛๔ኵྺ ዐ႐ڦ±1/2 LSBဃֶڟټཕାሞᅜፌዕኵྺዐ႐ڦ±1/2 LSBဃֶټᅜా้ڦक़ଉăኄᄣLj±1/2 LSBଉॺײ૬้क़ ܔᆌڦፌٷඹႹDAC߸ႎ୲नྺfmax = 1/tsăසࡕDAC ڦᄣԨᇑᄣԨक़Վࣅኵ๔ዕگᇀଉײLjሶᅜ๑ᆩ߸ ߸ڦႎ୲ă 3.46 றِஞ؋௬ओ றِஞ؋௬ओڦፌॅ݆ݛִ3.47๖ڦհႚă DACհิׂڦᇱᅺຕጴஇडೋၽࢅDACਸ࠲دڦ ჽփᅃዂ)ڍΣ-Δ႙DACॐࠓᅃ߲ኵ࠲ڥጀڦ૩ྔLj ࢫ௬ڦჺ༪ࣷॽᇎᅜ༪ஃ*ăறِཚሞዐଉײገ้࣑ፌ ٷLjᅺྺُ้DACዐڦᆶ࿋ۼᄲ߀Վă011...1ڟ100...0ገ ׂ࣑ิڦறِཚᇑ100...0ڟ011...1ገׂ࣑ิڦறِփ ཞLjᅺُՂႷݴ܀ڇဆዖ൧ăறِஞ؋௬ओ৽༬ۨ றِڦ௬ओLjཚᅜpV-sྺڇ࿋ઠ๖ǗᅺُLjྺ๑փཞ DACኮक़ڦԲডᆶᅪᅭLjՂႷኪڢDACڦଉײۉ უă๑ᆩ“றِీଉ”ኄᅃຍᇕփኟඓڦLjᅺྺڇ࿋pV-s ժփీଉ܈ڦଉՔጚă ٗ3.47ᅜੂLjᆶ6߲ీڦறِஞ؋௬ओႴᄲتă Rev. A | Page 15 of 21 www.BDTIC.com/ADI AN-282 ᆌᆩԴऻ ࣷ၄ଇْ)ሞ߲ଭሁฉ*Ljᅺׂܸࣷิኟ၀հܾڼڦ ߲ၿհLjස3.48๖ă൩ጀᅪLjዘႎं۠ڟలઊຯ༬ټ ాڦኟ၀հڦডߛၿհ݆୳հăవᇨ֪༬ۨ৫ற ِஞ؋௬ओᆅഐڦၿհ฿ኈLjᅺُLjྺକ؊ݴೠࠚዘࠓ DACۯڦༀႠీLjኄଇ߲༬ႠႴᄲ୯ă հஞ؋հႚ ጺၿհ฿ኈ(THD)ᅜᆩDSPरຍઠ֪ଉLjස3.49 ๖Ljഄዐܔ18࿋ᅼೕDAC AD1860ႜକ֪ăDAC֑ ᆩೕ୲ྺ990.5 Hzڦ18࿋ຕጴኟ၀հઠൻۯLjDAC߸ႎ ୲ྺ176.4 kHzăDSPܔ֪հႚڦ4096߲ᄣԨႜຕ ጴࣅتLjԈࡤኟ၀հڦ23߲ྜኝዜă֪ܔࡕኴ ႜ4096ۅޱᄾՎ࣑(FFT)ăࢫLjߵFFTࡕऺ໙ ጺၿհ฿ኈࢅSNRă။հ୳հഗݞኹ990.5 Hzٷڦናޗए հݴׯຕጴገ࣑ഗLjᅺُຕጴገ࣑ഗڦඇևྷݔ ጆோᆩᇀتሯำࢅၿհݴׯă3.50၂๖କଉײ ࢅ-20 dBଇዖ൧ۆڦ႙THDेሯำăᆌጀᅪLjኄ ၵ֪ଉዐժ࿄๑ᆩඁறِഗࢅMSBۙኝरຍă 3.47 ْገ࣑ᆶଇ߲၎࠲ڦறِஞ؋Ljॽഄ௬ओݴ՚ྺ1Ă 2Ă3Ă4ăُྔLj୯ᇑْ߳ገ࣑၎࠲“ڦ৫றِஞ؋”ᄺ ᆶᆩă৫றِஞ؋௬ओݴ՚ྺAREA 1 - AREA 2ࢅAREA 3 - AREA 4ăᅺُLjੂֱړDACຕ ֩ฉڦறِஞ؋௬ओ༬Ⴀ้Ljසࡕሰฆຫڥփࠕൣ ؤLjሶీࣷሰंׯၫă ஃ୳հᇑޏLjறِஞ؋௬ओԍփՎăॺ૬้क़ժ փጺᅪ࿆ጣறِஞ؋௬ओၭăԲডၙڦጒLjܔᇀ ْገ࣑LjDACڦ৫றِஞ؋௬ओྺ0LjनAREA 1 - AREA 2 = AREA 3 - AREA 4 = 0ăړLjሞၙጒူLjᆶ຺߲ ௬ओྺ0ă ၿհ฿ኈ ৫றِஞ؋௬ओᇑஓ၎࠲LjᅺُړDACዘࠓኟ၀հ้Lj ׂࣷิၿհăሞዘࠓኟ၀հڦᅃ߲ዜాLj৫ዐଉײறِ 3.48 18࿋ᅼೕDAC AD1860ڦFFT֪ 3.49 Rev. A | Page 16 of 21 www.BDTIC.com/ADI AN-282 ᆌᆩԴऻ ૧ᆩFFTڦڥ֪݆ݛ18࿋ᅼೕDAC AD1860ڦጺၿ հ฿ኈ Sin(x)/xೕ୲ࡐইၳᆌ ዘࠓDACڦᅜႚၡں๖ྺᅃဣଚਈႚஞ؋Ljഄ ڪ܈ᇀ߸ႎ୲ڛڦຕLjස3.52๖ă൩ጀᅪLj၎ܔᇀ گೕኵLjዘࠓ႑ࡽሞలઊຯ༬ೕ୲ट၌้گ3.92 dBăᆶ้ ሞDACኮࢫݣዃᅃ߲ݒၠsin(x)/x୳հഗLjᅜၯኟُၳᆌă SIN X/Xࡐই 3.50 ᆩSHAඁأDACڦறِ ᆩSHAᅜඁأDACڦறِLjස3.51๖ă৽ሞᄲॽႎ ຕ٪DACኮമLjॽSHAዃᇀԍఇ๕LjܸٗॽDAC ਸ࠲հᇑ߰ăSHAׂิڦਸ࠲ຨՎᇑஓ࠲Lj ժᅜ߸ႎೕ୲၄Ljᅺُඹᅟᇎᅜ୳أă SHAᆩፕඁհഗ 3.52 3.51 Rev. A | Page 17 of 21 www.BDTIC.com/ADI AN-282 ᆌᆩԴऻ ਸ࠲ۉඹ୳հഗ ਸ࠲ۉඹĐۉፆđ ႑ࡽ୳հᅃྜ܈ඇሞჄఇెᇘዐᆯᇸഗॲ(ཚۉ ߌĂۉፆࢅۉඹ)ڦದዃઠኴႜăࢫઠLjཚࡗ࣐؋ࢅሺᅮڦ ሏڦॺࠓݣᆶᇸ୳հഗྺ୳հഗยऺටᇵ༵ࠃକ߸ڦٷଳ ऄႠࢅ߸ߛڦႠీLjڍධሞఇె႑ࡽฉჄ߾ፕă DSPरຍ٣ิକ࿘ܸۨଳऄڦො้क़ຕጴ୳հഗLj֑ᄣ ఇె႑ࡽྜඇᆯຕኵऺ໙ઠتLjഄዐᆩڦᅃၵ୳հ໙ ݆݆ᆯჄ้क़ఇె୳հഗઠํ၄ă ਸ࠲ۉඹ୳հഗ(SCF)ᅃዖዐक़ૌ႙ڦഗॲLjጹࢇକჄ ้क़ࢅො้क़ଇݛ௬༬ኙăኄዖ୳հഗཚ૧ᆩCMOS ਸ࠲ࢅۉඹํ၄LjᅜఇెۉፆڦႜྺăᅺُLjႹ୳ܠհഗ ॐࠓۼᅜྜඇᆯڇႊೌഗॲઠํ၄LjܸႴྔևഗॲă ਸ࠲ۉඹ୳հഗᇑDSPरຍᅃഐLjሞᇕᅼࢅᅼೕټ႑ࡽ ᆌᆩዐ༬՚ᆶᆩăᆯᇀਸ࠲ۉඹ୳հഗ֑ᄣഗॲLjᅺُ ࠲ᇀො้क़֑ᄣڦᆶ߁ᆩᇀኄዖഗॲǖలઊຯ ༬ۨĂं۠ڪڪă ሞणۉׯୟዐLjژڇມዀਸ࠲૧ᆩCMOSਸ࠲ํ၄Ljᆯݥ ዘ۠ڦມ၎้ዓൻۯLjස3.55ăྺ๑ኄዖरຍᆶၳLjਸ ࠲ՂႷਏᆶڞڦگݥཚۉፆࢅۉ࠲ڦߛݥፆLjܸ CMOSरຍኟࡻీ༵ࠃኄᄣڦਸ࠲ă ୳հरຍ ਸ࠲ۉඹڦCMOSํ၄݆ݛ ■ ■ ■ ■ ■ ! 3.54 ৗናĂSAW୳հഗ ᇸഗॲ)ۉፆĂۉࢅߌۉඹ* ᆶᇸ୳հഗ)ۉፆĂۉඹࢅሏ*ݣ ਸ࠲ۉඹ୳հഗ)ᆩCMOSਸ࠲ࢅۉඹൽۉپፆ* ຕጴ୳հഗ)૧ᆩຕኵऺ໙ํ၄Ljీுᆶܔᆌ!ڦ ఇెഗॲ* 3.55 3.53 ૧ᆩ3.54๖ࢁۉڦገᅎ߁Ljᅜๆݴൣںؤକਸ࠲ ۉඹ؊ۉړፆڦएԨ߁ăසࡕۉඹٗV1ൎ࣑V2Ljሶॽ݀ ิຨ้ࢁۉገᅎLjΔQ = C(V1 - V2)LjୁࢁۉईୁV2ăഄ ዐԈࡤ्ڦยཉॲCுᆶۉزፆLjܸV1ࢅV2ྺၙۉ უᇸăසࡕਸ࠲ᅜగᅃ้ዓೕ୲fs)ዜྺT*ઠ࣮ਸࢇLjሶ V1ᇑV2ኮक़ॽᆶᅃ߲ೝୁۉiୁࡗLji =ΔQ/T = CAV/Tă༵ ࠃཞᄣٷၭೝڪڦୁۉၳۉፆ“R”ྺǖ ૧ᆩኄዖڪၳڦਸ࠲ۉඹۉፆLjᅜํ၄Ⴙدܠཥڦᇸ ࢅᆶᇸ୳հഗದዃă3.56၂๖କᅃ߲ڇटۅᇸRC୳ հഗतഄڪၳڦਸ࠲ۉඹ୳հഗăRC୳հഗڦ-3 dBೕ୲ ྺ1/(2πR1C1)ăܔᇀਸ࠲ۉඹ୳հഗLj f3dB = fsC1/(2πC2) ᇸRCྪஏڪڦၳਸ࠲ۉඹ “R” =ΔV/i = T/C = l/(Cfs) 3.56 Rev. A | Page 18 of 21 www.BDTIC.com/ADI AN-282 ᆌᆩԴऻ ൩ጀᅪLjܔᇀਸ࠲ۉඹ୳հഗLjټൽਦᇀ֑ᄣ୲ࢅۉ ඹኵኮԲăྺ๑้क़֑ᄣࢅࠌࢁۉၛڦᆖၚፌၭLjՂႷፔ ᅃ߲ዘᄲ्ยLjनfs>>f3dB)ཚᄲ൱50ڟ100Ԡ*ăᅺُLj ړ๑ᆩਸ࠲ۉඹ୳հഗ߁้Ljଣহೕ୲ᆯۉඹԲࢅ֑ᄣ ้ዓೕ୲ਦۨLjܾኁᅜݥඓᅎă Sin(x)/xೕ୲ࡐইၳᆌ ֑ᆩਸ࠲ۉඹ୳հഗႜᅼೕࢅᇕᅼ୳հLjᅜٷٷ३ၭ ᇸഗॲڦ٫ăࠓॺᅼೕ୳հഗ้Ljැᄲ๑ᆩࢇ ٷၭڇڦႊೌۉඹ)ሀ10 pF*Ljሶᄲ൱ۉፆሞ10 MΩຕଉपă ᅜ100 kHz୲ൎ࣑ᅃ߲1 pFۉඹᅜൟํ၄ۉፆኵLj Ⴔࡂ௬ओሀྺ0.01 mm2ăසࡕ๑ᆩܠৗࡂईકොरຍઠ ํ၄10 MΩۉፆLjሶႴ௬ओณᄲٷ100Ԡă SIN X/Xࡐই ዘࠓDACڦᅜႚၡں๖ྺᅃဣଚਈႚஞ؋Ljഄ ڪ܈ᇀ߸ႎ୲ڛڦຕLjස3.52๖ă൩ጀᅪLj၎ܔᇀ گೕኵLjዘࠓ႑ࡽሞలઊຯ༬ೕ୲ट၌้گ3.92 dBăᆶ้ ሞDACኮࢫݣዃᅃ߲ݒၠsin(x)/x୳հഗLjᅜၯኟُၳᆌă ਸ࠲ۉඹ୳հഗڦᆫ ■ ୳հഗټᇑۉඹԲׯԲ૩Ljܸփᇑਨܔኵ!ׯ Բ૩ ■ ■ ■ ୳հഗټໜ้ዓೕ୲ܸՎࣅ ! 3.58 ၟঢ়ۆఇె୳հഗᅃᄣۨᅭ ᅼೕೕ୲ᄲ൱گኵۉඹǖᅜ100 kSPSൎ࣑ 1 pFۉඹڪၳᇀ10 MΩۉፆ ■ ݥࢇDSP CMOS߾ᅝ 3.57 ਸ࠲ۉඹۉፆᇑഄۉඹࢅሏݣᅃഐ๑ᆩLjᅜํ၄دཥ RCᆶᇸ୳հഗዐ๑ᆩڦႹۉܠୟದዃăᇑຕጴ୳հഗփ ཞLjਸ࠲ۉඹ୳հഗྜඇᅜၟఇె୳հഗᅃᄣۨᅭă 3.58၂๖କᅃ߲ᅃჄ้क़ᆶᇸگཚRC୳հഗतഄܔᆌ ڦਸ࠲ۉඹ୳հഗă ྺକۉܔᇸ၍ሯำ߅ڪඡ႑ࡽํႜ؊ࠌڦݴఇᅞLjఇె ۉୟঢ়๑ᆩֶٷݣݴഗăਸ࠲ۉඹ୳հഗڦยऺᄺᅜ ๑ᆩኄၵᇱሶă3.59၂๖କᅃ߲ᆶᇸֶݴओݴഗतഄڪ ၳڦਸ࠲ۉඹăأକీ༵ࠃܔሯำڦଆࡻࠌఇᅞԲ (CMRR)ኮྔLjֶݴದዃ࣏ీܔਸ࠲֡ፕᆅഐڦຨՎํႜ ࠌఇᅞăਸ࠲ۉඹओݴഗঢ়ᆩᇀΣ-Δ႙ADCۙڦഗ ۉୟዐLjኄॽሞࢫ௬ڦჺ༪ࣷᇎᅜ༪ஃă ᆶᇸֶݴओݴഗतഄڪၳਸ࠲ۉඹ୳հഗ ਸ࠲ۉඹ୳հഗܔఇె႑ࡽႜ֑ᄣLjᅺُཚՂႷമዃ Ⴤ้क़ੇं۠୳հഗLjᅜၩأలઊຯ༬ೕ୲ᅜฉڦೕ ݴׯăᆯᇀਸ࠲ۉඹ୳հഗ֑ڦᄣ୲ཚᇺߛᇀഄཚ ټLjᅺُᅃ߲ڇटۅईມटۅRC୳հഗཚڟٳీ৽ฉຎ ణڦă 3.59 Rev. A | Page 19 of 21 www.BDTIC.com/ADI AN-282 ᆌᆩԴऻ ਸ࠲ۉඹ୳հഗᄺᆶܠዖਆ၌Ⴀࢅဃֶᇸăኻీሞᅼೕ ాټ๑ᆩLjᅺྺ૧ᆩణമڦCMOSरຍ࣏փీൟํں ၄ຕӥkHzᅜฉ֑ڦᄣ୲ăਸ࠲ۉඹࢅሏࣷݣᆅໜऐ ሯำLjႅୁۉሶీׂࣷิ฿ۙဃֶăઠጲਸ࠲Ԩวڦ ้ዓઍཚీׂࣷิཞօဃֶăፌࢫLjᆯᇀਸ࠲ۉඹ୳հ ഗ֑ᄣഗॲLjᅺُྺକݞኹं۠ᆅഐဃֶLjཚᄲ൱ড ֑ࡗڦٷᄣԲă ਸ࠲ۉඹ୳հഗڦਆ၌Ⴀࢅဃֶᇸ ■ ■ ■ ■ ਆ၌ᇀডگೕ୲ ሯำĂ฿ۙĂ฿ኈ ՂႷፏٗలઊຯ༬֑ᄣ݆ሶ ਸ࠲Ԩวࣷڞዂ้ዓઍཚ)ᄲ൱ੇं۠୳հഗDž 3.60 ֖࿔၅ 1. Frederic J. Harris, "On the Use of Windows for Harmonic Analysis with the Discrete Fourier Transform", IEEE Proceedings, Vol. 66, No. 1, Jan. 1978, pp. 51-83. 2. Joey Doernberg, Hae-Seung Lee, David A. Hodges, "Full Speed Testing of A/D Converters", IEEE Journal of Solid State Circuits, Vol. SC-19, No. 6, Dec. 1984, pp. 820-827. 3. James R. Andrews, Barry A. Bell, Norris S. Nahman, and Eugene E. Baldwin, "Reference Waveform Flat Pulse Generator", IEEE Transactions on Instrumentation and Measurement, Vol. IM-32, No. 1, March 1983, pp. 27-32. 4. Brendan Coleman, Pat Meehan, John Reidy and Pat Weeks, "Coherent Sampling Helps When Specifying DSP A/D Converters", EDN, October 15, 1987, pp. 145-152. 5. Howard K Schoenwetter, "A Programmable Voltage Step Generator for Testing Waveform Recorders", IEEE Transactions on Instrumentation and Measurement, Vol. IM-33, No. 3, Sept. 1984, pp. 196-200. 6. Robert W. Ramirez, The FFT: Fundamental and Concepts, Prentice-Hall, 1985. 7. R.B. Blackman and J.W. Tukey, The Measurement of Power Spectra, Dover Publications, New York, 1958. 8. James J. Colotti, "Digital Dynamic Analysis of A/D Conversion Systems Through Evaluation Software Based on FFT/DFT Analy sis", RF Expo East 1987 Proceedings, Cardiff Publishing Co., pp. 245-272. 9. Sid Kaufman, "Multistage Error Correcting A/D Converters", Electronic Products, April 18, 1983, pp. 103-110. 10. HP Journal, Nov. 1982, Vol. 33, No. 11 11. HP Product Note 5180A-2. 12. HP Journal, April 1988, Vol. 39, No. 2. 13. HP Journal, June 1988, Vol. 39, No. 3. 14. Dan Sheingold, Editor, Analog-to-Digital Conversion Handbook, Third Edition, Prentice-Hall, 1986. Rev. A | Page 20 of 21 www.BDTIC.com/ADI AN-282 ᆌᆩԴऻ 15. W.R. Bennett, "Spectra of Quantized Signals", Bell System Technical Journal, No. 27, July 1948, pp. 446-472. 16. G.A. Gray and G.W. Zeoli, "Quantization and Saturation Noise Due to Analog-Digital Conversion", IEEE Transactions on Aerospace and Electronic Systems, Jan. 1971, pp. 222-223. 17. M.J. Tant, The White Noise Book, Marconi Instruments, July 1974. 18. W.A. Kester, "PCM Signal Codecs for Video Applications", SMPTE Journal, No. 88, November 1979, pp. 770-778. 19. Lawrence Rabiner and Bernard Gold, Theory and Application of Digital Signal Processing, Prentice-Hall, 1975. 20. Matthew Mahoney, DSP -Based Testing of Analog and Mixed-Signal Circuits, IEEE Computer Society Press, Washington, D.C., 1987. 21. IEEE Trial-Use Standard for Digitizing Waveform Recorders, No. 1057-1988. 22. Richard J. Higgins, Digital Signal Processing in VSLI, Prentice-Hall, 1990. 23. High Speed Design Seminar, Analog Devices, 1990. 24. M. S. Ghausi and K R. Laker, Modern Filter Design: Active RC and Switched Capacitors, Prentice Hall, 1981. 25. Brodersen, Gray, and Hodges, MOS Switched-Capacitor Filters, Proc. IEEE Vol. 67, January 1979, pp. 61 - 65. 26. J. T. Caves, et. al., Sampled Analog Filtering Using Switched Capacitors as Resistor Equivalents, IEEE J. Solid State Circuits VoL SC-12, pp. 592 - 599. Rev. A | Page 21 of 21 www.BDTIC.com/ADI