LINEAR TECHNOLOGY DC2222A Oversampling ADCs nwere Configurable Digital Filter
LTC2500-32/LTC2508-32/LTC2512-24: 32-Bit/24-Bit Oversampling ADCs nwere Configurable Digital Filter
Nkọwa
Ihe ngosi sekit 2222A nwere LTC®2500-32, LTC2508-32 na LTC2512-24 ADC. LTC2500-32, LTC2508-32 na LTC2512-24 bụ ike dị ala, obere mkpọtụ, oke ọsọ, 32-bit/24-bit SAR ADCs nwere nzacha ọnụọgụ dijitalụ agbakwunyere na-arụ ọrụ site na otu ọkọnọ 2.5V. Ederede na-esote na-ezo aka na LTC2508-32 mana ọ metụtara akụkụ niile, naanị ihe dị iche bụ s.ample ọnụego na ọnụ ọgụgụ nke ibe n'ibe. DC2222A na-egosiputa arụmọrụ DC na AC nke LTC2508-32 yana njikọ DC590 ma ọ bụ DC2026 QuikEval™ na DC890 PScope™ data nchịkọta. Jiri DC590 ma ọ bụ DC2026 gosi arụmọrụ DC dị ka mkpọtụ elu ruo-elu yana linearity DC. Jiri DC890 ma ọ bụrụ sampAchọrọ ọnụego ling ma ọ bụ gosipụta arụmọrụ AC dịka SNR, THD, SINAD na SFDR. Ezubere DC2222A iji gosi ntọ ala akwadoro, ntinye akụrụngwa na nhọrọ, ụzọ na ngafe maka ADC a.
Nhazi files maka bọọdụ sekit a gụnyere schematic, BOM na okirikiri nhọrọ ukwuu dị na http://www.linear.com/demo/DC2222A ma ọ bụ lelee koodu QR dị n'azụ bọọdụ ahụ. L, LT, LTC, LTM, Linear Technology na akara akara Linear bụ ụghalaahịa edenyere n'akwụkwọ ikikere yana QuikEval na PScope bụ ụghalaahịa nke Linear Technology Corporation. Ighalaahịa ndị ọzọ niile bụ ihe onwunwe nke ndị nwe ha.
Ọgụgụ 1. DC2222A Njikọ Eserese
Ngwa ịmalite usoro
Tebụl 1. DC2222A Mgbakọ na Nhọrọ elekere
Nzukọ Ụdị |
U1 IKPEHE Nọmba |
Mpụta MAX DATA Ọnụọgụgụ |
DF |
BITS |
MAX CLK IN FREQ |
Mpụta |
MODE |
NKEWA |
DC2222A-A | LTC2500IDKD-32 | 175kps | 4 | 32 | 70Mhz | A | Enweghị Nyochaa | 100 |
173kps | 4 | 32 | 70Mhz | A | Nyochaa | 101 | ||
250kps | 4 | 32 | 43Mhz | A | Ekesara Gụọ | 43 | ||
250kps | 4 | 32 | 45Mhz | A | Nyochaa + Dis. Gụọ | 45 | ||
800kps | 1 | 24 | 80Mhz | B | 100 | |||
DC2222A-B | LTC2508IDKD-32 | 3.472kps | 256 | 32 | 80Mhz | A | Enweghị Nyochaa | 90 |
2.900kps | 256 | 32 | 75Mhz | A | Nyochaa | 101 | ||
3.906kps | 256 | 32 | 43Mhz | A | Ekesara Gụọ | 43 | ||
3.906kps | 256 | 32 | 45Mhz | A | Nyochaa + Dis. Gụọ | 45 | ||
900kps | 1 | 14 | 90Mhz | B | 100 | |||
DC2222A-C | LTC2512IDKD-24 | 350.877kps | 4 | 24 | 80Mhz | A | Enweghị Nyochaa | 57 |
303.03kps | 4 | 24 | 80Mhz | A | Nyochaa | 66 | ||
400kps | 4 | 24 | 62.4Mhz | A | Ekesara Gụọ | 39 | ||
400kps | 4 | 24 | 70.4Mhz | A | Nyochaa + Dis. Gụọ | 44 | ||
1.5Mps | 1 | 14 | 85.5Mhz | B | 57
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Lelee ka ị hụ na edobere jumpers niile dịka akọwara na ngalaba DC2222A Jumpers. Karịsịa, gbaa mbọ hụ na edobere VCCIO (JP3) na ọnọdụ 2.5V. Ijikwa DC2222A na DC890 ka JP3 nke DC2222A nọ n'ọnọdụ 3.3V ga-eme ka arụrụ ọrụ ama ama na SNR na THD. Njikọ jumper ndabara na-ahazi ADC ka ọ jiri nrụtụ aka na ndị na-achịkọta. Ntinye analọgụ bụ DC jikọtara ya na ndabara. Jikọọ DC2222A na DC890 USB High Speed Data Collection Board site na iji njikọ P1. (Ejikọla onye njikwa PScope na onye njikwa QuikEval n'otu oge.) Na-esote, jikọọ DC890 na PC nnabata na eriri USB A/B stan-dard. Tinye ± 9V n'ọnụ ọnụ ndị egosiri. Ọzọ tinye isi iyi dị iche iche jitter dị ala na J2 na J4.
Jikọọ obere jitter 2.5VP-P sine wave ma ọ bụ square wave na njikọ J1, na-eji Tebụl 1 dị ka ntuziaka maka oge elekere kwesịrị ekwesị. Rịba ama na J1 nwere 49.9Ω nkwụsị nkwụsị n'ala.
Gbaa ngwa PScope (ụdị PScope.exe K86 ma ọ bụ karịa) nke DC890 wetara ma ọ bụ budata ya na ya. www.linear.com/software.
Akwụkwọ ngwanrọ zuru ezu dị site na menu enyemaka. Enwere ike ibudata mmelite site na menu Ngwaọrụ. Lelee maka mmelite kwa oge ka enwere ike ịgbakwunye atụmatụ ọhụrụ.
Ngwa PScope kwesịrị ịmata DC2222A wee hazie onwe ya na-akpaghị aka. Nhazi ndabara bụ iji Verify na Distributed Read adịghị ahọrọ na Down Sampling Factor (DF) atọrọ na uru kacha nta enwere ike. Iji gbanwee nke a, pịa na Ntọala Demo Bd Nhọrọ nke PScope Tool Bar dị ka egosiri na Figure 2. Igbe Nhazi Nhọrọ nke egosiri na Figures 3a, 3b na 3c na-enye ohere ka mmepụta ADC, DF, Verify na Distributed Read to set. N'ihe banyere LTC2500 ọ nwekwara ike ịhọrọ ụdị nzacha, nweta compres-sion na nweta mgbasawanye. Ọ bụrụ na ahọpụtaghị Verify mgbe ahụ usoro mmalite ngwa ngwa
A ga-emechi ọnụ ọgụgụ kacha nta nke ibe n'ibe. Ọ bụrụ na ahọpụtara Verify ọnụ ọgụgụ nke ibe n'ibe emechiri ga-abawanye site na asatọ nke gụnyere ọnụọgụ samples were maka mmepụta ugbu a. Ọgụgụ ekesara na-enye ohere iji elekere nwayọ nwayọ site na ịgbasa data emechiri emechi n'ọtụtụ s.amples. Enwere ike ịtọ DF n'ofe oke nke ngwaọrụ eji arụ ọrụ kpebiri. Ịbawanye DF ga-eme ka SNR dịkwuo mma. N'usoro iwu, SNR ga-akawanye mma site na 6dB ma ọ bụrụ na ala sampling factor na-abawanye site na ihe anọ. Na omume, mkpọtụ ntụnye aka ga-emecha mechie nkwalite SNR. Ịbawanye REF bypass capacitor (C20) ma ọ bụ iji obere mkpọtụ ntụaka mpụga ga-agbatị oke a.
Pịa bọtịnụ Anakọta (Lee eserese 4) ka ịmalite inweta data. Bọtịnụ Anakọta wee gbanwee gaa kwụsịtụ, nke enwere ike ịpị ka kwụsị nweta data.
Ọgụgụ 2. PScope Toolbar
Ngwa ịmalite usoro
DC590 ma ọ bụ DC2026 Usoro mmalite ngwa ngwa
Ọ dị mkpa! Iji zere mmebi nke DC2222A, jide n'aka na JP6 nke DC590 ma ọ bụ JP3 nke DC2026 ka atọrọ na 3.3V tupu jikọọ na DC2222A.
VCCIO (JP3) nke DC2222A kwesịrị ịdị na 3.3V posi-tion maka DC590 ma ọ bụ DC2026 (QuikEval) ọrụ. Iji jiri QuikEval njikwa na DC2222A, ọ dị mkpa itinye -9V na ala na -9V na GND ọnụ. 9V maka DC2222A bụ onye njikwa QuikEval. Jikọọ QuikEval njikwa na PC nnabata na eriri USB A/B ọkọlọtọ. Jikọọ DC2222A na QuikEval njikwa na-eji eriri rib-bon 14-conductor wetara. (Ejikọla ma onye njikwa QuikEval na PScope n'otu oge.) Tinye isi iyi mgbama na J4 na J2. Enweghị mgbama elekere dị mkpa na J1 mgbe ị na-eji njikwa QuikEval. A na-enye mgbama elekere site na njikọ QuikEval (J3).
Gbaa ngwa QuikEval (ụdị K109 ma ọ bụ karịa) nke ejiri QuikEval njikwa wetara ma ọ bụ budata ya na ya.
DC590 ma ọ bụ DC2026 Usoro mmalite ngwa ngwa
Ịpị bọtịnụ nhazi ga-ebulite nhọrọ nhọrọ Con-figuration yiri nke egosiri maka PScope ma e wezụga na ọ bụ naanị mmepụta enyo dị ma ọ nweghị nhọrọ maka nyochaa na ikesa agụ. Ịbawanye DF ga-ebelata mkpọtụ dị ka e gosiri na histo-gram nke Figure 6. A ga-ebelata mkpọtụ site na mgbọrọgwụ square nke ọnụ ọgụgụ nke ugboro ole s.amples na-abawanye. Na omume, dị ka ntinye voltage na-abawanye mkpọtụ nrụtụ aka ga-emecha kwụsị mmụba mkpọtụ.

Ọgụgụ 6. QuikEval Histogram nwere DF = 1024

Ike DC
DC2222A chọrọ ± 9VDC wee dọta ihe dịka 115mA/–18mA mgbe ejiri elekere 90MHz na-arụ ọrụ. Ọtụtụ n'ime ihe ndị dị ugbu a bụ ndị FPGA na-eri, op amps, ndị na-achịkwa na mgbagha pụrụ iche na bọọdụ. Ntinye 9VDC voltage na-enye ike ADC site na ndị na-achịkwa LT1763 nke na-enye nchebe pụọ na nhụsianya mgbanwe mberede. Ndị nchịkwa ọzọ na-enye ike maka FPGA na op amps. Lee eserese 1 maka nkọwa njikọ.
Mgbe ị na-eji njikwa DC890 ọ dị mkpa ịnye obere jitter 2.5VP-P (Ọ bụrụ na VCCIO nọ na ọnọdụ 3.3V, elekere. amplitude kwesịrị ịbụ 3.3VP-P.) sine ma ọ bụ square ife ka J1. Ntinye elekere bụ AC jikọtara ya mere ọkwa DC nke mgbama elekere adịghị mkpa. A na-atụ aro onye nrụpụta elekere dịka Rohde & Schwarz SMB100A. Ọbụna onye na-emepụta elekere dị mma nwere ike ịmalite ịmepụta jitter a na-ahụ anya na obere ugboro. Ya mere, a na-atụ aro maka ala sample ọnụego iji kewaa ala elekere ugboro dị elu na ugboro ntinye achọrọ. Egosiri nha nke ugboro elekere na ọnụego ntụgharị na Tebụl 1. Ọ bụrụ na a ga-eji ezi uche mee ntinye elekere, a na-atụ aro ka ewepụ 49.9Ω terminator (R5). Ọnụ na-ebili nwayọọ nwayọọ nwere ike imebi SNR nke onye ntụgharị n'ihu elu ampakara ngosi ntinye ugboro dị elu.
Mwepụta data yiri nke sitere na bọọdụ a (0V ruo 2.5V na ndabara), ọ bụrụ na ejikọtaghị ya na DC890, enwere ike nweta ya site na onye nyocha mgbagha, wee webata ya na mpempe akwụkwọ, ma ọ bụ ngwugwu mgbakọ na mwepụ dabere n'ụdị nhazi akara dijitalụ chọrọ. . N'aka nke ọzọ, enwere ike ịnye data ahụ ozugbo na sekit ngwa. Jiri pin 50 nke P1 iji jide data. Enwere ike ijide data ahụ site na iji ihu ọdịda nke mgbaama a. Na nyochaa ọnọdụ a chọrọ akụkụ abụọ na-ada ada maka data ọ bụlaample. Enwere ike gbanwee ọkwa mgbama mmepụta data na P1 ka ọ bụrụ 0V gaa na 3.3V ma ọ bụrụ na sekit ngwa chọrọ volta dị elu.tage. Emezuru nke a site na ịkwaga VCCIO (JP3) gaa na ọnọdụ 3.3V.
Ntuziaka ndabara bụ ntụaka LTC6655 5V. Ọ bụrụ na ejiri ntụaka mpụga, ọ ga-edozi ngwa ngwa n'ihu glitches na ntụtụ REF. N'ịtụ aka na sekit ntụaka nke eserese 7, desolder R37 ma tinye akwụkwọ ntụaka mpụta voltage gaa na ọdụ VREF.

Ọkwọ ụgbọala ndabara maka ntinye analọgụ nke ADC na DC2222A ka egosiri na foto 8a na 8b. Sekit ndị a
chekwaa mgbama ntinye 0V ruo 5V etinyere na AIN+ na AIN-. Na mgbakwunye, eriri sekit ndị a na-amachi akara ntinye na ntinye ADC. Ọ bụrụ na a ga-eji ọkwọ ụgbọala LTC2508-32 Figure 8a maka ngwa AC, a na-atụ aro ka ewepụ capaci-tors C71 na C73 ma jiri WIMA P/N SMDTC04470XA00KT00 4.7µF obere ihe nkiri capacitors ma ọ bụ dakọtara na ọnọdụ C90 na C91. Nke a ga-enye mgbagọ kacha ala.
DC2222A nhazi


A na-anwale bọọdụ ngosi a n'ụlọ site na iji FFT nke ebili mmiri sine etinyere na ntinye dị iche nke bọọdụ ngosi. Nke a gụnyere iji isi iyi elekere jitter dị ala, yana ihe nrụpụta sinusoidal generator dị iche na ugboro dị nso 200Hz. Ọkwa mgbama ntinye dị ihe dịka -1dBFS. A na-atụgharị ọkwa ntinye ma kpochaa ya na sekit egosiri na eserese 9. A na-egosipụta FFT nke a na-enweta na DC2222A na Figure 4. Rịba ama na iji gbakọọ ezigbo SNR, ọkwa mgbaàmà (F1). amplitude = -1dB) ka agbakwunyere azụ na SNR nke PScope gosipụtara. Ya na example egosiri na eserese 4 nke a pụtara na SNR n'ezie ga-abụ 123.54dB kama 122.54dB nke PScope gosipụtara. Inweta nchikota RMS nke SNR na THD agbakọgharịrị na-ewepụta SIAD nke 117.75dB. Enwetara THD ahụ site na iji ikike WIMA nhọrọ.
Ọgụgụ 9. Ọkwa mgbanwe dị iche iche
Enwere ọtụtụ ọnọdụ ndị nwere ike iwepụta nsonaazụ na-eduhie eduhie mgbe ị na-enyocha ADC. Otu ihe a na-ahụkarị bụ iji ugboro ugboro na-enye ihe ntụgharị nri, ya bụ obere-ọtụtụ sample ọnụego, na nke ga-emega naanị obere subset nke ekwe omume mmepụta codes. Ụzọ kwesịrị ekwesị bụ ịhọrọ ugboro M/N maka ntinye sine ugboro ugboro. N bụ ọnụọgụ nke samples na FFT. M bụ nọmba bụ isi n'etiti otu na N/2. Mụbaa M/N site na sample ọnụego iji nweta ntinye sine ugboro ugboro. Ihe atụ ọzọ nwere ike iwepụta nsonaazụ na-adịghị mma bụ ma ọ bụrụ na ịnweghị igwe na-emepụta sine nke nwere ike ịme ugboro ugboro ppm.
DC2222A nhazi
izi ezi ma ọ bụ ọ bụrụ na enweghị ike ịkpọchi ya na ugboro elekere. Ị nwere ike iji FFT nwere windo iji belata ntapu ma ọ bụ gbasaa nke bụ isi, iji nweta nso nso nke arụmọrụ ADC. Ọ bụrụ na achọrọ windo, a na-atụ aro windo Blackman-Harris 92dB. Ọ bụrụ otu ampA na-eji ihe ọkụ ọkụ ma ọ bụ ebe elekere na-adịghị mma na-eme mkpọtụ, windo agaghị eme ka SNR dịkwuo mma.
Nhazi
Dị ka ọ dị na ADC ọ bụla dị elu, akụkụ a na-enwe mmetụta maka nhazi. Mpaghara ozugbo gbara ADC gburugburu na DC2222A kwesịrị iji ya mee ihe dị ka ntụzịaka maka ntinye, na ntụgharị nke akụkụ dị iche iche metụtara ADC. Nke a bụ ụfọdụ ihe ị ga-echeta mgbe ị na-ewepụta bọọdụ maka LTC2508-32. Ụgbọ elu ala dị mkpa iji nweta arụmọrụ kachasị. Debe capacitors uzo ka nso inye ntụtụ dị ka o kwere mee. Jiri nloghachi impedance dị ala jikọọ ozugbo na ụgbọ elu ala maka capacitor ụzọ ọ bụla. Iji nhazi ihe nlebara anya gburugburu ntinye analọgụ ga-ebelata mmetụta nke ihe nje nje. Chekwa akara ntinye analọgụ na ala iji belata njikọ site na akara ndị ọzọ. Debe akara dị mkpụmkpụ ka enwere ike.
Nhọrọ akụrụngwa
Mgbe ị na-anya obere mkpọtụ, obere mgbagha ADC dị ka LTC2508-32, nhọrọ akụrụngwa dị mkpa ka ọ ghara imebi arụmọrụ. Ndị na-emegide kwesịrị inwe ụkpụrụ dị ala iji belata mkpọtụ na mgbagha. A na-atụ aro ndị na-emegide ihe nkiri metal iji belata nhụsianya nke ọkụ onwe ya kpatara. N'ihi obere voltaji hatage coefficients, ka n'ihu belata distortion NPO ma ọ bụ silver mica capaci-tors kwesịrị iji. Ihe nchekwa ọ bụla a na-eji maka ngwa AC kwesịrị inwe mgbagha dị ala, obere mkpọtụ na oge nhazi ngwa ngwa dịka LTC6363 na LT6202. Maka ngwa ziri ezi DC, LTC2057 bụkwa ihe a na-anabata ma ọ bụrụ na etinyere nzacha mmepụta zuru oke.
DC2222A JUMPERS
Nkọwa
- JP1: EEPROM bụ naanị maka ụlọ ọrụ mmepụta ihe. Hapụ nke a na ọnọdụ WP ndabara.
- JP2: Njikọta na-ahọrọ AC ma ọ bụ DC njikọ nke AIN-. Ntọala ndabara bụ DC.
- JP3: VCCIO na-edobe ọkwa mmepụta na P1 ka ọ bụrụ 3.3V ma ọ bụ 2.5V. Jiri 2.5V iji interface na DC890 nke bụ ntọala ndabara. Jiri 3.3V ka interface na DC590 ma ọ bụ DC2026.
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JP4: CM na-esetịpụ echiche DC maka AIN + na AIN- ma ọ bụrụ na etinyere AC. Iji mee ka njikọ AC nwee ike, R35 na R36 (R = 1k) nke egosiri na nhazi nke eserese 10 ga-etinyerịrị. Ịwụnye resistors ndị a ga-eweda THD nke mgbama ntinye na ADC. VREF/2 bụ ntọala ndabara. Ọ bụrụ na ahọpụtara EXT ndenye nkịtị mode voltagEnwere ike ịtọ ya site na ọdụ ụgbọ ala E5 (EXT_CM).
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JP5: Njikọta na-ahọrọ njikọ AC ma ọ bụ DC nke AIN +. Ntọala ndabara bụ DC.
Akwụkwọ ntuziaka DEMO DC2222A
BODO Ngosipụta OKWU dị mkpa
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LINEAR TECHNOLOGY DC2222A Oversampling ADCs nwere Configurable Digital Filter [pdf] Ntuziaka onye ọrụ DC2222A, ihe karịrịampling ADCs nwere Configurable Digital Filter, DC2222A Oversampling ADCs nwere Configurable Digital Filter, ADCs nwere Configurable Digital Filter, OversampNdị ADC, ADCs |