View AD9245_2167903.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

14-bit, 80 msps, 3 v a/d converter AD9245 fea t ures single 3 v supp ly operation (2. 7 v to 3. 6 v) snr = 72.7 dbc to nyq u ist sfdr = 87.6 dbc to nyqu ist low power: 366 mw differential inp u t with 500 mhz bandwidth on-chip reference and sample-and-hold dnl = 0. 5 ls b flexible analog input: 1 v p-p to 2 v p-p range offset binary o r twos comple ment data format clock du ty cy cle stabilizer a pplic a t io ns high end me di cal imaging eq uipment if sampling in communications receivers: wcdma, cdm a -one, cdm a - 2000, t d s-c d ma battery-powered instrum e nts hand-hel d scopemeters low cost digital oscilloscopes power sensitive militar y appli c ations gener a l de scription the AD9245 is a m o n o l i thic, sin g le 3 v s u p p l y , 14-b i t, 80 ms ps a n alog-t o-d i g i ta l co n v er t e r f e a t ur in g a h i gh per f o r m a n c e s a m p le- a n d -h ol d a m pl if ier (s h a ) a nd vol t a g e refer e n c e. t h e AD9245 us es a m u l t is t a g e dif f er en tial p i p e lin e d a r c h i t ec t u r e w i t h output e r r o r c o r r e c t i on l o g i c to prov i d e 1 4 - b it a c c u r a c y at 80 ms ps an d g u a r a n t e e n o missin g co des o v er t h e f u l l o p er a t - in g t e m p er a t ur e ra n g e . the wide b a n d wi d t h, t r u l y dif f er en t i a l s h a al lo ws a va r i ety o f us er -s e l e c t a b l e i n p u t ran g es an d co mm on m o de s, in cl udin g sin g le-e n d e d a p p l ica t ion s . i t is sui t a b le fo r m u l t i p lexe d sys t em s tha t s w i t ch f u l l -s cale v o l t a g e le ve ls in s u cce s si v e c h a n n e ls, an d fo r s a m p lin g sing le-cha n n el in pu ts a t f r e q ue n c i e s w e l l b e yo nd t h e n y q u ist ra t e . c o m b ine d w i t h p o w e r a nd co st s a vi n g s o v er p r evio u s l y a v a i l a b l e a n alog-t o-dig i t a l con v er t e rs, th e AD9245 is sui t ab le fo r a p pl ica t ion s i n co m m unic a t ion s , im a g ing, a nd m e dica l u l t r as ound . a sin g le-e nde d c l o c k in p u t is us e d t o con t r o l al l in t e r n al con - v e rsio n c y cles. a d u ty c y cle s t a b i l i z er (d cs) c o m p e n s a t e s fo r wid e va r i a t io n s in t h e clo c k d u t y c y cle w h i l e ma in t a ini n g func ti onal bl oc k di a g ram 03583-b-001 drvdd avdd agnd 0.5v clk pdwn mode dgnd otr vin+ vin? reft refb AD9245 vref sense sha a/d mdac1 4 16 14 3 a/d 8-stage 1 1/2-bit pipeline ref select clock duty cycle stabilizer mode select correction logic output buffers d13 (msb) d0 (lsb) f i gur e 1 . f u nctio n al bl oc k dia g r a m exce l l en t o v eral l ad c p e r f o r ma n c e . th e dig i t a l o u t p ut da t a is p r es en t e d i n s t r a ig h t b i na r y o r tw os co m p le m e n t fo r m a t s. an out - of - r ang e ( o t r ) s i g n a l i n d i c a te s a n ove r f l ow c o nd it i o n t h at ca n b e us e d wi t h t h e m o st sig n i f ica n t b i t t o deter m in e lo w o r h i g h ove r f l ow . f a br i c ate d on a n a d v a nc e d c m o s pro c e s s , t h e AD9245 is a v a i l a b l e in a 32-lead lfcs p and is s p ecif ie d o v er t h e i n d u s t r i al t e m p er a t ur e ra n g e (C40c t o +85 c). pr oduc t highligh t s 1. the AD9245 o p era t es f r o m a sin g le 3 v p o w e r s u p p l y a nd fe a t ur es a s e p a r a te dig i t a l o u t p u t dr i v er su p p ly to acco m m o - da t e 2.5 v a nd 3 . 3 v log i c fa milies. 2. o p era t ing a t 80 ms ps, th e ad9 245 co n s u m es a lo w 366 mw . 3. the p a ten t e d sh a in p u t m a in t a in s exce l l en t p e r f o r ma n c e fo r in p u t f r eq uen c ies u p t o 100 mh z, and can be co nf igur ed f o r sin g le-e n d e d o r dif f er en t i al op er a t io n. 4. the AD9245 is p i n com p a t i b le wi t h t h e ad921 5, ad9235, a nd ad9236. this al lo ws a sim p lif i ed mig r a t ion f r o m 10 b i ts t o 14 b i ts an d 2 0 ms ps t o 80 ms ps. 5. t h e cl o c k d c s m a i n t a i n s ove r a l l a d c p e r f or manc e ove r a wid e ra n g e o f clo c k p u ls e w i d t h s . 6. the otr o u t p ut b i t i n di c a t e s w h e n t h e sig n al is b e yo n d t h e se l e ct e d in p u t ra n g e . in fo rmation furn ished by an alog d e v i c e s is believed to be accurate and reliable. how e ver, n o resp on sibili ty is assume d b y a n alog de vices fo r its use, nor for an y i n fri n geme nt s of p a t e nt s or ot h e r ri ght s o f th ird parties th at may result fro m its use . s p ecificatio n s subj ec t to ch an g e witho u t n o tice. no licen s e is g r an te d by implicati o n or ot herwi s e u n der a n y p a t e nt or p a t e nt ri ghts of analog de v i ces. trademarks an d registered tra d ema r ks are the prop erty o f their respective ow ners. one technolog y way, p.o . box 9106, norwood, ma 02062-9106, u.s.a. t e l: 781. 329. 4 700 www.analog.com fax: 781. 326. 87 03 ? 2003 analog de vices, i n c. al l r i ght s r e ser v ed . rev. b
AD9245 table of contents AD9245Cd c s p ecif ic a t io n s ............................................................ 3 AD9245Ca c s p ecif ica t ion s ............................................................. 4 AD9245Cd i g i ta l s p ecif ica t io n s ....................................................... 5 AD9245Cs w i t chin g s p ec if ica t io n s ................................................. 6 e x pla n a t ion o f t e st l e v e l s ........................................................... 6 a b s o l u t e m a xim u m r a t i n g s ............................................................ 7 ther mal resis t a n c e ...................................................................... 7 es d c a u t ion .................................................................................. 7 d e f i ni t i on s o f s p e c if ic a t io n s ........................................................... 8 p i n c o nf igura t io n an d f u n c t i onal d e s c r i p t io ns .......................... 9 e q ui valen t cir c ui ts ......................................................................... 10 t y p i cal p e r f o r ma n c e c h a r ac t e r i s t ics ........................................... 11 the o r y o f o p era t io n ...................................................................... 14 analog i n p u t and refer e n c e o v er vie w ................................... 14 c l o c k i n p u t c o n s idera t ion s ...................................................... 15 j i t t e r c o n s idera t io n s .................................................................. 16 p o w e r dis s i p a t io n an d s t an d b y m o de .................................... 16 dig i t a l o u t p u t s . .......................................................................... 16 t i min g ......................................................................................... 17 v o l t a g e refer e nce ....................................................................... 17 i n t e r n al refer e n c e c o nne c t i o n ................................................ 17 e x t e r n al refer e n c e o p era t ion . ................................................. 18 o p era t io nal m o de s e le c t io n . .................................................... 18 e v al ua t i o n b o a r d ........................................................................ 18 o u t l in e dim e n s io n s ....................................................................... 25 or der i n g g u ide . ......................................................................... 25 revisi on h i s t or y rev i s i o n b 10/03da ta sheet cha n ged f r o m re v . a t o re v . b c h a n g e s t o f i gu r e 33 ..................................................................... 17 5/03da ta sh e e t cha n g e d f r o m re v . 0 t o re v . a c h a n g e s t o f i gu r e 30 .................................................................... 15 c h a n g e s t o f i gu r e 37 ..................................................................... 19 c h a n g e s t o f i gu r e 38 ..................................................................... 20 c h a n g e s t o f i gu r e 39 ...................................................................... 21 c h a n g e s t o t a b l e 10 ....................................................................... 24 c h a n g e s t o t h e o r d e rin g g u id e ........................................... 25 r e v. b | pa ge 2 o f 2 8
AD9245 AD9245?dc s p ecifications table 1. avdd = 3 v, dr vdd = 2. 5 v, sa mple rate = 80 msps, 2 v p- p di ffere nt i a l in put , 1.0 v ext e rna l re fere nce, unles s ot herwi s e not e d ad92 45bcp parameter temp test leve l m i n t y p m a x unit r e s o l u t i o n f u l l v i 1 4 b i t s a c c u r a c no m i ssing cod e s full vi guaranteed offset error 1 f u l l v i 0 . 3 0 1 . 2 f s r gain error 25c v 0.28 fsr gain error 1 f u l l v i 0 . 7 0 4 . 1 6 f s r differential non l inearity (dnl) 2 f u l l v i 0 . 5 1 . 0 l s b integral nonlinearity (in l ) 2 f u l l v i 1 . 4 5 . 1 5 l s b tempe r atu r e drift offset error 1 f u l l v 1 0 p p m c gain error full v 12 ppmc gain error 1 f u l l v 1 7 p p m c inter n al voltage refe rence output voltage error ( 1 v m o d e ) full vi 3 34 mv load regulation 1.0 ma 25c v 2 mv output voltage error (0.5 v mode) 25c v 6 mv load regulation 0.5 ma 25c v 1 mv input refer r e d noise vref = 0.5 v 25c v 1.86 lsb rms vref = 1.0 v 25c v 1.17 lsb rms analog in put input span, vre f = 0.5 v full iv 1 v p-p input span, vre f = 1.0 v full iv 2 v p-p input capacitance 3 f u l l v 7 p f referenc e in p u t resis t anc e full v 7 k poer suppli e s supply voltage a v d d f u l l i v 2 . 7 3 . 0 3 . 6 v d r v d d f u l l i v 2 . 2 5 2 . 5 3 . 6 v supply current iavdd 2 f u l l v i 1 2 2 1 3 8 m a idrvdd 2 2 5 c v 9 m a p s r r 2 5 c v 0 . 0 1 f s r poer consu m ption low freuency input 4 2 5 c v 3 6 6 m standby power 5 25c v 1 . 0 m 1 ith a 1.0 v inte rnal ref e re nce . 2 mea s ure d at the m a ximum clock rate, f in = 2.4 mh , full -s c a l e s i ne wave, with approx imatel y 5 pf l o a d ing on each output bit. 3 input capacitance refer s to the e f fectiv e capacitance between one di ffe rential input pin and agn d . refe r to for the e uival e nt a n al o g input s t ructure . figure 4 4 m e a s ured at a c sp ecif ication cond itio ns witho ut o u tput d r ive r s . 5 st a n dby pow e r i s m e a s ure d wi t h a dc i n put , cl pi n i n a c t i ve (i .e., s e t t o avd d or agn d ) . r e v. b pa ge 3 o f 2 8
AD9245 AD9245?ac specifications table 2. avdd = 3 v, dr vdd = 2. 5 v, sa mple rate = 80 msps , 2 v p- p di ffere nt i a l in put , 1.0 v ext e rna l re fere nce, a i n = C0.5 db f s , dcs o ff, u n les s ot herwi s e not e d ad92 45bcp parameter temp test leve l m i n t y p m a x unit signal-to-noi se ratio (snr) f in = 2.4 mh full vi 71.1 db 25c v 7 3 . 3 d b f in = 40 mh 25c v 72.7 db f in = 70 mh full iv 70.5 db 25c v 7 1 . 7 d b f in = 100 mh 25c v 70.2 db signal-to-noi se and d i stor tion (si n ad) f in = 2.4 mh full vi 70.7 db 25c v 7 3 . 2 d b f in = 40 mh 25c v 72.5 db f in = 70 mh full iv 69.9 db 25c v 7 1 . 2 d b f in = 100 mh 25c v 69.6 db effective num b er of bits (e n o b) f in = 2.4 mh full vi 11.5 bits 25c v 1 1 . 9 b i t s f in = 40 mh 25c v 11.8 bits f in = 70 mh full iv 11.3 bits 25c v 1 1 . 5 b i t s f in = 100 mh 25c v 11.3 bits o rst seco n d o r thi r d f in = 2.4 mh full vi C76.5 dbc 25c v C 9 2 . 8 d b c f in = 40 mh 25c v C87.6 dbc f in = 70 mh full iv C75.7 dbc 25c v C 8 1 . 6 d b c f in = 100 mh 25c v C79.0 dbc spurious-free dnamic rang e (sfdr) f in = 2.4 mh full vi 76.5 dbc 25c v 9 2 . 8 d b c f in = 40 mh 25c v 87.6 dbc f in = 70 mh full iv 75.7 dbc 25c v 8 1 . 6 d b c f in = 100 mh 25c v 79.0 dbc r e v. b pa ge 4 o f 2 8
AD9245 AD9245?digital specifications table 3. avdd = 3 v, dr vdd = 2. 5 v, 1. 0 v e x ternal r e ference, unless otherwise note d ad92 45bcp parameter temp test leve l m i n t y p m a x unit logic inputs ( c l, pdn) high level input voltage full iv 2.0 v low level input voltage full iv 0.8 v high level input current full iv C10 10 a low level input current full iv C10 10 a input c a p a c i t a n c e f u l l v 2 p f digital o u tpu t bits (d0Cd13, o t r) 1 drvdd = 3.3 v high level output voltage (ioh = 50 a) full iv 3.29 v high level output voltage (ioh = 0.5 ma) full iv 3.25 v low level outp ut voltage (ioh = 1.6 ma) full iv 0.2 v low level outp ut voltage (ioh = 50 a) full iv 0.05 v drvdd = 2.5 v high level output voltage (ioh = 50 a) full iv 2.49 v high level output voltage (ioh = 0.5 ma) full iv 2.45 v low level outp ut voltage (ioh = 1.6 ma) full iv 0.2 v low level outp ut voltage (ioh = 50 a) full iv 0.05 v 1 out p ut volt a g e lev e ls m e a s u r ed wi t h 5 pf l o a d on ea ch o u t p ut . r e v. b pa ge 5 o f 2 8
AD9245 AD9245Cswitching specifications table 4. avdd = 3 v, dr vdd = 2. 5 v, u n less otherwise noted ad92 45bcp parameter temp test leve l m i n t y p m a x unit clo c k input p a rame ters maximum conv ersion rate full vi 80 msps minimum conversion rate full v 1 msps clk period full v 12.5 ns clk pulsewid t h high 1 full v 4 . 6 n s clk pulsewid t h low 1 f u l l v 4 . 6 n s data outpu t param ete r s output propagation delay (t pd ) 2 f u l l v 4 . 2 n s pipeline del a y ( l atency) full v 7 cycles aperture delay ( t a ) f u l l v 1 n s aperture uncertainty (j itter, t j ) f u l l v 0 . 3 p s r m s wake-up time 3 f u l l v 7 m s out-of-range recovery t i me full v 2 cycles 1 wi t h dut y cyc l e st a b i l i z er (d c s ) en a b le d. 2 out p ut propa g a t i o n de la y i s m e a s ur e d from clk 50% t r a n si t i on t o d a ta 50 % t r a n si t i on , wi t h 5 pf loa d . 3 wa ke- up t i m e i s de pen d a n t on t h e va l u e o f t h e dec o upli n g ca pa ci t o rs; t y pi ca l va lu es sh own wi t h 0.1 f a n d 10 f ca pa ci t o rs on re ft and re fb. t a 2.0ns min t pd = 6.0ns max 03583-b-002 n 9n 8 n 7n 6 n 5n 4 n 3n 2 n 1 n analog input clk data out n 1 n n+1 n+2 n+3 n+4 n+5 n+6 n+7 n+8 f i g u re 2. ti ming d i ag r a m explanation of test levels test leve l definitions i 100% production tested. ii 100% production tested at 25c and guaranteed by de sign and characterizati on at specified temperatures. iii sample tested only. iv parameter is guaranteed by desi gn and charact e rization testing . v parameter is a typical va lue only. vi 100% production tested at 25c and gu aranteed by design and characterizati on for industrial temperature rang e. r e v. b | pa ge 6 o f 2 8
AD9245 absolute maximum ratings table 5. ad92 45 absolute maximum ratings parameter ith respect t o min max unit electrical a v d d a g n d C 0 . 3 3 . 9 v d r v d d d g n d C 0 . 3 3 . 9 v a g n d d g n d C 0 . 3 0 . 3 v a v d d d r v d d C 3 . 9 3 . 9 v d0Cd13 dgnd C0.3 drvdd 0.3 v cl, mode agnd C0.3 avdd 0.3 v vin, vinC agnd C0.3 avdd 0.3 v vref agnd C0.3 avdd 0.3 v sense agnd C0.3 avdd 0.3 v reft, refb agnd C0.3 avdd 0.3 v pdn agnd C0.3 avdd 0.3 v environment a l storage temperature C65 125 c operating tem p erature range C40 85 c lead temperature range (sol dering 10 s e c) 300 c junction tempe r ature 150 c s t r e s s es a b o v e t h os e lis t e d u n de r a b s o l u t e m a xi m u m r a t i n g s ma y c a us e p e r m a n en t dama ge t o t h e de vice . this is a s t r e s s ra t i n g onl y a nd f u n c t i o n al op era t io n o f t h e de v i ce a t t h es e o r a n y o t h e r con d i t io n s ab o v e t h o s e i n di ca t e d in t h e op era t io nal s e c t io n o f t h is sp e c if ic a t io n is no t im plie d . e x p o sur e t o a b s o l u te max i m u m ra t i ng co ndi t i on s fo r ex ten d e d p e r i o d s ma y a f fe c t de vice r e l i ab i l i t y . thermal resistance ja is sp e c if ie d fo r t h e w o rst - ca s e co ndi t i on s o n a 4-l a yer b o a r d in st i l l a i r , in acc o r d an ce w i t h ei ajes d 51 -1. table 6. therm a l resistance package type
AD9245 definitions of specifications a n a l og bandw i d t h (f u l l p o w e r ba ndw i d t h) t he a n alog in p u t f r e q uen c y a t w h ich t h e sp e c t r a l p o w e r o f t h e f u ndam e n t a l f r eq uen c y (as d e t e r m in e d b y t h e fft a n al ysis) i s r e d u ce d b y 3 db . ap e r t u r e d e l a y ( t a ) th e de l a y b e twe e n t h e 5 0 % p o i n t o f t h e r i sin g e d g e o f t h e clo c k an d t h e in s t a n t a t w h i c h t h e a n alog in p u t is s a m p le d . ap e r t u r e un c e r t a i n t y ( j i t t e r , t j ) t h e sa m p l e -t o- sa m p l e v a ria - tio n in a p er t u r e de l a y . in t e g r a l no n l i n e a r i t y ( i n l )t h e devia t i o n o f ea c h in d i v i d u al co de f r o m a li ne dr a w n f r o m nega t i ve f u l l s c a l e t h r o ug h p o si t i ve f u l l s c ale . th e p o in t us e d as n e g a ti v e f u l l s c ale o c c u rs ls b be f o r e th e f i r s t cod e tra n si ti o n . p o si ti v e full scale i s d e f i n e d a s a lev e l 1 ls b b e yo n d t h e l a s t c o de tra n si tion. th e de via t io n is m e as ur ed f r o m th e middle o f eac h p a r t ic u l a r co de t o the tr ue st r a ig h t l i ne. d i f f erenti a l n o n l i n e a r i ty ( d n l , n o mi s s i n g c o d e s ) an ide a l a d c exhib i ts co de t r an si t i o n s t h a t a r e exac t l y 1 ls b a p a r t. dnl is t h e d e vi a t io n f r o m t h i s i d e a l va l u e . g u a r a n t e e d n o miss - in g co des t o 14-b i t r e s o l u tio n indic a t e s tha t al l 1 6384 co des m u s t b e p r es e n t o v er al l o p era t in g ra n g es. off s et e r r o r t he ma jo r ca r r y tra n si tio n sh o u ld o c cur f o r a n a n alog val u e ls b b e lo w vin+ = vinC. of fs et er r o r is d e f i n e d a s t h e devia t i o n o f th e act u al tra n si ti o n f r o m th a t po in t. ga in er r o r t h e f i rs t co de tran si tio n sh o u ld o c c u r a t a n a n alog v a l u e l s b a b o v e n e ga ti v e full scale . th e la s t tra n si ti o n shou l d o c c u r a t an an a l o g v a lu e 1 l s b b e l o w t h e p o s i t i ve f u l l s c ale . ga i n er r o r is t h e de vi a t io n o f t h e ac t u al dif f er en c e b e tw e e n f i rst and la st co d e t r a n si t i o n s and t h e i d e a l dif f er en c e b e tw e e n f i rst and la st co de t r a n si t i o n s. t e m p er a t ure d r ift th e tem p era t ur e dr if t fo r o f fs et er r o r a n d ga in er r o r s p e c i f ies t h e maxi m u m cha n ge f r o m t h e i n i t ial (25c) val u e t o t h e va l u e a t t mi n or t max . po w e r s u p p l y r e j e c t i o n r a t i o th e c h a n ge in f u ll scale f r o m th e v a l u e wi th t h e su p p l y a t t h e m i n i m u m lim i t t o th e v a l u e w i th th e s u p p l y a t i t s m a x i m u m l i m i t . t o t a l ha r m on i c d i s t or t i on ( t h d ) 1 t h e ra tio o f th e rm s in p u t sig n al am pli t ude t o t h e r m s val u e o f t h e s u m o f t h e f i rs t six ha r m o n ic com p on e n ts. si g n a l - t o - n o i s e a n d d i s t or t i on ( s i n a d ) 1 th e ra ti o o f th e r m s in p u t sig n a l a m pli t ude t o t h e r m s val u e o f t h e s u m o f al l o t h e r s p ectral co m p o n en t s be l o w th e n y q u i s t f r eq ue n c y , in c l ud- in g ha r m onics b u t excl udin g d c . e f f e c t iv e n u mb er of b i ts ( en o b si n a d n t f n f a ( ) ? = sinad enob s n a t n r a t s nr 1 t a t f t n p t n aa p t t t a f t f a t p ta p n n t t n t f n n t f t a n a n s p f d na r a n s fd r 1 t f f n nb t n t n p t n aa p t ant p a p n a tp a p p n n ta a n t a a n t t n s f d r 1 ta t f t a f t n p t t nt t a f t p a p p n n t t p ap p n n ta a n t animdp t c p tan d t c p t t n a n t f t ta t t p ft n t l 1 t a t t a a t p f a n p t t n t t p ft n t l t a t a t a n a t t p f a t n f nan ap t a t mn c n n r a t t a t a t t sn r f t t a n a n af n p n ta n b t a an t t ma c n n r a t t a t a t p a a t t t n p f o t p t p p a a t n da t pd t a t n t n a n t t n a t a t n a o t f r a n r t t t t ta f t a d c t a t an a n pt af t a t an t n f 1 a p t f a t 1a n a t f a f 1 n a t f a t 1 p t f a 1 ac s p ecif ications may be rep o rted in dbc (d egra d e s a s si gn a l lev e l s a r e lower e d ) or i n dbfs (a lwa y s r e la t e d ba c k t o c o n v ert e r fu ll s c a l e). r e v. b | pa ge 8 o f 2 8
AD9245 pin conf iguration and fu nctional descri ptions 03583-b-022 dnc 1 clk 2 dnc 3 pdwn 4 (lsb) d0 5 d1 6 d2 7 d3 8 24 vref 23 sense 22 mode 21 otr 20 d13 (msb) 19 d12 18 d11 17 d10 32 a v d d 31 a g n d 30 vin 29 vin + 28 a g n d 27 a v d d 26 r e ft 25 r e fb d4 9 d5 1 0 d6 1 1 d7 1 2 d8 1 3 d9 1 4 dgnd 1 5 drv dd 1 6 AD9245 csp top view (not to scale) f i g u re 3. 32-l e ad l f csp table 7. pin function d e scriptio ns32-lead lfcsp (cp package) pin no. mnemonic description 1, 3 dnc do not connect 2 clk clock in put pin 4 pdwn power-down function select 5 to 14, 17 to 20 d0 (lsb) to d13 (msb) data output bit s 1 5 d g n d d i g i t a l o u t p u t g r o u n d 16 drvdd digital output driver supply 2 1 o t r o u t - o f - r a n g e i n d i c a t o r 22 mode data format select and dc s mo de sel e ction (s e e ) 23 sense reference mode selection (see table 8) 24 vref voltage reference input/ output 25 refb differential reference (C) 26 reft differential reference (+) 27, 32 avdd analog power s u pply 28, 31 agnd analog ground 29 vin+ analog input pin (+) 30 vinC analog input pin (C) t a b l e 9 r e v. b | pa ge 9 o f 2 8
AD9245 equivalent circuits avdd v in, vin 03583-b -003 f i re 4 e i v e n t a n o int c i r it 03583-b -004 avdd mode 20 ? rev. b | page 10 of 28
AD9245 typical perf orm ance cha r acte ristics a v d d 30 v , d r vd d 2 5 v , s e r t e 80 ms ps, d c s di e , t a 25c , 2 v - di e r en ti i n t , ain C 0 5 bfs, v r e f 1 0 v e ter n , n e ot e r i e n o te frequency mh amp l itude bfs 0 5 10 15 20 25 30 35 120 0 1 0 2 0 3 0 4 0 5 0 0 0 8 0 9 0 100 110 40 0358 3-b -032 ain 05bfs snr 32b enob 118 bits sfdr 928 b f i gure 8. s i ngl e t o n e 8 k fft @ 2 . 5 m h z freuenc (mhz) amp l itude (dbfs ) 0 5 10 15 20 25 30 35 120 0 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 0 100 110 40 0358 3-b -023 ain = 0.5dbfs snr = 72.7dbc enob = 11.8 bits sfdr = 87.6 dbc f i gure 9. s i ngl e t o n e 8 k fft @ 3 9 mh z freuenc (mhz) amp l itude (dbfs ) 0 5 10 15 20 25 30 35 120 0 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 0 100 110 40 0358 3-b -024 ain = 0.5dbfs snr = 71.7dbc enob = 11.5 bits sfdr = 81.6 dbc f i gure 10. sing le t o ne 8 k ff t @ 70 mh z input amplitude (dbfs) s nr/s f dr (dbc and dbfs ) 3 0 25 2 0 15 10 5 40 50 60 70 80 90 100 0 0358 3-b -033 sfdr (dbfs) snr (dbc) sfdr = 90dbc reference line sfdr (dbc) snr (dbfs) f i g u re 11. sing le t o ne snr / sfdr v s . in put a m pl it ude (a in ) @ 2. 5 m h z input amplitude (dbfs) s nr/s f dr (dbc and dbfs ) 3 0 25 2 0 15 10 5 40 50 60 70 80 90 100 0 0358 3-b -034 sfdr (dbfs) snr (dbc) sfdr = 90dbc reference line sfdr (dbc) snr (dbfs) f i gure 12. sing le t o ne snr/sfdr vs. in put a m plitude ( a in ) @ 39 mh z sample rate (msps) s nr/s f dr (dbc ) 0 2 04 06 08 0 50 60 70 80 90 100 100 03583-b-025 sfdr (diff) sfdr (se) snr (diff) snr (se) f i g u re 13. snr / sf d r v s . s a mp le r a t e @ 40 m h z rev. b page 11 of 28
AD9245 freuency (mhz) amp l itude (dbfs ) 0 5 10 15 20 25 30 35 120 110 100 9 0 8 0 7 0 6 0 5 0 4 0 3 0 2 0 1 0 0 40 0358 3-b -029 ain = 6.5dbfs snr = 73.4dbfs sfdr = 86.0dbfs f i gure 14. t w o - t o n e 8 k fft @ 3 0 m h z and 31 m h z freuency (mhz) amp l itude (dbfs ) 0 5 10 15 20 25 30 35 120 110 100 9 0 8 0 7 0 6 0 5 0 4 0 3 0 2 0 1 0 0 40 0358 3-b -030 ain = 6.5dbfs snr = 72.7dbfs sfdr = 78.8dbfs f i gure 15. t w o - t o n e 8 k fft @ 6 9 m h z and 70 m h z code inl ( l sb) 0 2048 4096 6144 8192 10240 12288 14336 1.5 1.5 1.0 0.5 0 0.5 1.0 16384 0358 3-b -026 f i g u re 16. t y pic a l i n l input amplitude (dbfs) s nr/s f dr (dbc and dbfs ) 3 0 2 7 2 4 2 1 1 8 1 5 1 2 9 40 100 90 80 70 60 50 6 03583-b-031 sfdr = 90dbc reference line sfdr (dbfs) sfdr (dbc) snr (dbfs) snr (dbc) f i gure 17. t w o - t o n e snr/sf dr v s . input a m pl itude @ 3 0 mh z and 31 mh z input amplitude (dbfs) s nr/s f dr (dbc and dbfs ) 3 0 2 7 2 4 2 1 1 8 1 5 1 2 9 40 100 90 80 70 60 50 6 0358 3-b -027 sfdr = 90dbc reference line sfdr (dbfs) sfdr (dbc) snr (dbfs) snr (dbc) f i gure 18. t w o - t o n e snr/sf dr v s . input a m pl itude @ 6 9 mh z and 70 mh z code dnl (ls b ) 0 2048 4096 6144 8192 10240 12288 14336 1.0 1.0 0.8 0.6 0.4 0.2 0 0.2 0.4 0.6 0.8 16384 0358 3-b -028 f i g u re 19. t y pic a l d n l rev. b | page 12 of 28
AD9245 input frequency mh s nr b 0 2 55 0 5 1 0 0 5 5 40 rev. b page 13 of 28
AD9245 theory of operation the AD9245 a r c h i t ec t u r e co n s is ts o f a f r o n t-end s a m p l e an d h o ld am plif ier (s h a ) fol l o w e d b y a p i p e li n e d s w i t ch e d c a p a ci - to r ad c. the p i p e li n e d a d c is divide d i n to t h r e e s e c t io n s , co n s ist i n g o f a 4 - b i t f i rst st a g e fol l o w e d b y eig h t 1.5-b i t st a g es a nd a f i nal 3 - b i t f l as h. e a ch s t a g e p r o v ides s u f f i cien t o v erl a p t o co rr ect f o r f l a s h e r r o r s i n th e p r eced in g s t a g e s . t h e q u a n t i z e d output s f r om e a ch st age are c o mbi n e d i n to a f i n a l 1 4 - bit re su lt in t h e dig i tal c o r r e c tio n log i c. th e p i p e lin e d a r chi t e c t u r e p e r - mi ts t h e f i rs t s t ag e t o o p era t e o n a ne w in p u t s a m p le , w h i l e t h e r e ma inin g s t a g es o p era t e o n p r e c e d in g s a m p les. sa m p l i n g o c c u rs o n th e r i sin g edg e o f t h e c l o c k. e a ch s t a g e o f t h e p i p e li n e , excl udin g t h e last, co n s is ts o f a lo w re s o lut i on f l a s h a d c c o n n e c te d to a s w i t c h e d c a p a c i tor d a c a nd i n t e rst a ge resid u e a m pl if ier (md a c). the r e sid u e a m pl if ier ma g n if ies t h e di f f er en ce b e tw e e n t h e r e co n s t r uc t e d d a c o u t p u t a nd t h e f l ash i n p u t fo r t h e n e xt s t a g e in t h e pi p e li n e . o n e b i t o f r e d u ndan c y is us ed in each s t a g e t o facili t a te dig i tal co r r e c tio n of f l ash e r rors . the l a st st age s i m p ly c o ns ists of a f l as h a d c . the i n p u t st a g e co n t a i n s a dif f er en t i al s h a t h a t ca n b e ac - co u p le d o r dc-c o u ple d i n dif f er en t i a l o r sin g le- e n d e d m o des. the o u t p u t -s t a g i n g b l o c k alig n s t h e da t a , c a r r i es o u t t h e er r o r co r r e c t i o n , a nd p a s s es t h e da t a to t h e o u t p u t b u f f ers. th e o u t p u t b u f f e r s are p o we re d f r om a s e p a r a te su p p ly , a l l o wing a d j u st me n t of t h e output vo lt age s w i n g . d u r i ng p o we r - d o w n , t h e output b u f f ers go in t o a hig h im p e dance st a t e . analog input and re ference overview the a n alog in pu t t o t h e a d 924 5 is a dif f er en t i a l sw i t ch e d - ca p a c i t o r s h a tha t has b e en de sig n e d fo r o p tim u m p e r f o r m- a n c e w h i l e p r o c es sin g a dif f er en t i al i n p u t sig n al . the s h a in p u t ca n su p p o r t a w i de co m m on- m o d e r a n g e ( v c m ) a nd ma i n t a i n e x c e l l e n t p e r f or m a n c e, a s s h ow n i n fi . a n i n put c o m m on - m o d e vo lt age of m i d s upply m i n i m i z e s s i g n a l - d e p e nd e n t e r ror s and prov i d e s opt i m u m p e r f or m a n c e. g u re 2 6 f i gure 26. snr, sfd r vs. c o mmon-m ode l e vel common-mode level (v) s nr/s f dr (dbc ) 0.5 1.0 1.5 2.0 2.5 50 100 95 90 85 80 75 70 65 60 55 3.0 0358 3-b -039 sfdr (2.5mhz) sfdr (39mhz) snr (2.5mhz) snr (39mhz) refer r in g t o f , t h e clo c k sig n al al t e r n a t e l y sw i t ch es t h e s h a b e t w e e n s a m p le m o d e and h o l d m o de. w h e n t h e s h a is swi t ch e d in t o s a m p le m o de , t h e sig n al s o ur ce m u s t be ca p a b l e o f c h a r g i n g th e s a m p le c a p a ci t o rs a n d s e t t l i n g wi t h in one-half of a cl o c k c y cl e. a s m a l l res i stor in s e r i es wi t h e a ch in p u t c a n h e l p r e d u ce t h e p e ak t r a n sie n t c u r r en t r e q u ir e d f r o m t h e o u t p ut s t a g e o f t h e dr ivin g s o ur ce . als o , a smal l s h u n t c a p a ci t o r ca n be place d acr o s s t h e in p u ts t o p r o v ide d y na mic cha r g i n g c u r r en ts. this p a s s i v e n e t w o r k cr e a t e s a l o w-p a s s f i l t er a t t h e ad c s in p u t; t h er efo r e , t h e p r e c is e val u es a r e dep e n d e n t u p o n t h e a p plic a t ion. i n i f un ders am pling a p plic a t ion s , an y sh u n t ca p a c i t o rs sh o u ld b e r e d u ce d o r r e m o v e d . i n com b ina t ion wi th t h e dr ivi n g s o ur ce im p e dan c e, t h e y w o u l d lim i t t h e i n p u t b a ndwi d t h . i gur e 2 7 f i g u re 27. swit che d - c apaci t o r s h a i n put 03583-b -012 h h vin vin c par c par t t 5pf 5pf t t f o r b e st dy n a m i c p e r f or m a nc e, t h e s o u r c e i m p e d a nc e s d r iv i n g vin an d vin s h o u l d b e ma tc h e d s u c h tha t c o mm on-mo d e s e t t ling er r o rs a r e symm et r i cal . th e s e er r o rs a r e r e d u ce d b y t h e c o m m on - m o d e re e c t i o n of t h e a d c . an in t e r n al dif f er en t i a l r e fer e nce b u f f er cr e a t e s p o si t i v e and ne g a t i v e re f e re n c e vo lt age s , reft an refb t a t f n t p an f t a d c t tpt n f t f n f f tt pp a n t re ft an refb t a anp a n a f n a f () () () vref refb reft span vref avdd refb vref avdd reft = ? = ? = + = reft an refb t a a t a a t t pp t a an f n t n t n p t p a n tt a f t vref t a t n t n a t a f n a n p n t a p p t f a f v 1 v a t tnt a a n a n t t n m a s n rp f a n a tt ad2 t i n t n a r f n c nn t n rev. b | page 14 of 28
AD9245 03583-b -014 AD9245 vin vin avdd agnd 33 ? ? ? ? ? vref vcm min = () vref avdd vcm max + = differenti a l input config urations s p r e i o us l de ta il ed o p t i u pe rf o r a n e i s a i e ed ile dr i in g te d in a dif f er en tial in p u t o nf igura t io n o r as e and a p p l i a t io n s t e d dif f er en tial dr i er p r o ides ee l l en t p e r f o r a ne and a f l ei le i n t e r f ae to t e d c e o u t p u t o on- o d e o l t a g e o f t e d is easil s e t t o dd and t e dr i er a n e o nf igur e d in a sa l l en e f i l t e r top o l o g to pr o i d e a nd l i i t i ng of t e i n put s i g n a l d i i d dd p-p ? ? ? ? ? ? ? ? ? single-ended input configuration sin g le-e nde d in p u t a p r o i d e ade u a te p e r f o r a n e i n ost-s en s i t i e a p plia t io n s i n t is o nf igura t ion t er e is a deg r ad a t ion i n s d a nd di stor t i o n p e r f o r a n e d u e to t e la rg e in pu t o on- o d e s i n g s e e o e e r if t e s o ur e i p e dan es on e a in p u t a r e a t e d t er e s o u ld e l i t t le ef f e t on s p e r f o r a n e d e t a ils a tp i a l s i ng l e - e nd e d i n put o n f i g u r a t i o n i gur e i gur e i gure sing le -ended input config ur ation -- d i i dd d p-p ? ? ? ? ? ? ?
AD9245 jitter considerations h i g h s p e e d , hig h r e s o l u t i o n ad cs a r e s e n s i t i v e t o t h e quali t y o f t h e clo c k in p u t. the deg r a d a t ion in s n r a t a g i v e n i n p u t f r e - qu e n c y ( f input ) du e on l y t o ap e r tu re j i tt e r ( t j ) ca n be calc ula t ed w i th th e f o ll o w i n g e q ua t i o n : [ ] j input t f 2 snr = log 20 i n t h e e q ua t i o n , th e r m s a p e r t u r e j i t t er r e p r es en ts th e r o o t -m e a n s q ua r e o f all ji t t er s o ur ces , w h i c h in cl ude t h e clock in p u t, a n alog in p u t si g n al , a n d ad c a p er t u r e ji t t er s p ecif ica t io n. if un ders a m - plin g a p plica t i o n s a r e p a r t icu l a r ly s e n s i t i v e t o ji t t er (s e e f i gur e 31). the c l o c k in p u t s h o u ld be tr e a ted as an a n alog sig n al in c a s e s w h er e a p er t u r e ji t t er ma y a f fe c t t h e dyna mic ran g e o f t h e AD9245. p o w e r s u p p lies f o r c l o c k dr i v ers sh o u ld b e s e p a ra t e d f r o m t h e ad c o u t p ut dr i v er s u p p lies t o a v o i d m o d u l a t i ng t h e clo c k sig n al wi t h dig i t a l n o is e . l o w ji t ter , cr ys tal co n t r o l l e d os cil l a t o r s ma k e th e bes t c l o c k s o ur ces. i f th e c l o c k is g e n e ra t e d f rom anot he r t y p e of s o u r c e ( b y g a t i n g , d i v i d i n g , or ot he r me t h - od s ) , i t s h o u ld b e r e ti m e d b y t h e o r i g i n al c l oc k a t th e la s t s t ep . input frequency (mhz) s nr (dbc ) 1 40 75 70 65 60 55 50 45 1000 100 10 03583-b-041 0.2ps measured snr 0.5ps 1.0ps 1.5ps 2.0ps 2.5ps 3.0ps f i gure 3 1 . snr vs . input f r equenc y a n d j i tter power diss ipat io n an d sta n db y mode a s sh o w n i n , th e p o w e r dis s i p a t ed b y th e AD9245 is prop or t i on a l to it s s a m p l e r a te. t h e d i g i t a l p o we r d i ss ip a t i o n i s deter m i n e d p r ima r i l y b y t h e st r e n g t h o f t h e di g i t a l dr i v ers and t h e lo ad on e a ch o u t p u t b i t. the maxim u m d r vd d c u r r en t ( i dr v d d ) ca n be c a lc ula t e d as f i g u r e 3 2 f i g u re 32. p o wer a n d cur r ent v s . s a m p le r a t e @ 2.5 m h z f i gur e 3 2 n f c v i clk load drvdd drvdd = w h er e n is t h e n u m b er o f o u t p u t b i ts, 14 in t h e cas e o f t h e AD9245. this maxim u m c u r r en t o c c u rs w h en ev er y o u t p u t b i t s w i t ch e s o n ev er y c l oc k c y c l e , i . e . , a full- s cale sq ua r e w a v e a t th e ny q u i s t f r e q u e n c y , f cl k /2. i n p r ac t i ce , t h e dr v d d c u r r en t wi l l b e est a b l ish e d b y t h e a v er a g e n u m b er o f o u t p u t b i ts s w i t ching, whic h wil l b e det e r m in ed b y t h e s a m p le r a t e and the c h a r ac t e r - i s ti cs o f th e a n alog i n p u t s i gn al. sample rate (msps) total power (mw) curre nt (ma) 10 20 30 40 50 60 70 80 90 300 325 350 375 400 425 0 20 40 60 80 100 120 140 100 03583-b -035 analog current total power digital current re d u cin g t h e ca p a ci t i v e lo ad p r es en t e d t o t h e ou t p ut dr i v ers can mini mi ze d i g i t a l p o wer co n s um p t io n. t h e d a t a i n w a s t a k e n w i th th e sa m e o p e r a t i n g co n d i t i o n s a s th e t y p i c a l p e r- f o r m a n ce cha r ac t e r i s t ics, a nd wi t h a 5 pf lo ad o n eac h o u t p u t dr i v er . b y as s e r t in g the p d wn p i n hig h , th e AD9245 is p l ace d in s t a n d b y m o d e . i n th i s s t a t e , th e a d c t y p i call y d i s s i p a t e s 1 mw if t h e c l k an d analog in p u ts a r e s t a t ic. d u r i n g s t an db y , th e o u t p u t d r i v er s a r e p l a c ed i n a h i g h i m pe d a n c e s t a t e . reas s e r t in g t h e p d wn p i n lo w r e t u r n s th e AD9245 t o i t s n o r m a l o p er a t i o na l m o de. l o w p o w e r dissi p a t io n i n st andb y m o de is achi e v e d b y sh ut t i ng d o w n t h e re f e re nc e, re f e re n c e bu f f e r , and bi a s i n g ne t w or k s . t h e deco u p lin g ca p a ci t o rs o n reft an d refb a r e dis c ha rg ed w h en en ter i n g st and b y m o de an d t h e n m u st b e r e ch arge d w h en re tu r n i n g to no r m a l op e r a t i o n . a s a re su lt , t h e w a ke - u p t i m e i s rel a te d to t h e t i me sp e n t i n st andb y mo de, and shor te r st andb y c y cl e s re su lt i n prop or t i on a l ly shor te r w a ke - u p t i me s . w i t h t h e r e co mmen d e d 0.1 f a nd 10 f deco u p lin g ca p a ci t o rs o n ref t a nd ref b , i t t a k e s a p p r o x im a t ely 1 s e co nd to f u l l y dis c ha rge t h e re f e re nc e bu f f e r d e c o upl i ng c a p a c i tor s a n d 7 m s to re store f u l l op e r a t i o n . digi tal ou tputs the a d 92 45 o u t p ut dr i v ers c a n b e co nf ig ur e d t o i n ter f a c e w i t h 2.5 v or 3 . 3 v lo g i c fami lies b y ma tc hing dr vd d t o t h e dig i ta l s u p p ly o f t h e i n ter fac e d log i c. the out p u t dr i v ers a r e si ze d t o p r o - v i de s u f f i cie n t out p u t c u r r e n t t o dr i v e a w i de v a r i ety o f log i c fami l i e s . h o we ver , l a rge dr i v e c u r r en ts te nd t o c a us e c u r r e n t gli t ch e s o n t h e s u p p li es t h a t ma y a f f e ct co n v e r t e r pe rf o r m a n c e . a p p l ica t io n s r e q u i r in g t h e ad c t o d r i v e la r g e ca pa ci t i v e lo a d s o r la rge fano uts ma y r e q u ire exter nal b u f f ers o r l a tches. a s d e t a i l ed i n , th e d a ta f o rm a t ca n be s e le ct ed f o r e i th e r of f s e t bi n a r y or t w o s c o m p l e m e n t . t a b l e 9 rev. b | page 16 of 28
AD9245 timi ng the AD9245 p r o v ides l a t c h e d da ta ou t p u t s wi t h a p i p e lin e dela y of s e ve n cl o c k c y cl e s . d a t a output s are a v ai l a bl e one prop ag a - ti o n de la y (t pd ) a f t e r th e ri s i n g ed g e o f th e c l oc k s i gn al . r e f e r t o f o r a d e ta iled t i m i n g di a g ra m . f i g u r e 2 the len g t h o f t h e o u t p ut da t a li n e s and t h e lo ads place d o n th em s h o u ld be m i n i m i z e d t o r e d u ce tra n s i en t s w i t h i n t h e AD9245. th es e tra n sien ts can deg r ade t h e con v er t e r s d y na mic pe rf o r m a n c e . the lo w e s t typ i cal con v ersio n r a t e o f t h e ad92 45 is 1 ms ps. a t clo c k r a tes b e lo w 1 ms ps, d y n a mic p e r f o r ma n c e ma y deg r ad e. voltage r e ference a s t a b le an d acc u ra t e 0.5 v v o l t a g e r e fer e n c e is b u i l t i n t o t h e AD9245. th e in p u t ra n g e ca n b e ad j u s t ed b y var y in g th e r e f e r - en c e v o l t a g e a p p l ied t o t h e AD9245 usin g ei ther th e in t e r n al re f e re nc e or an e x te r n a l ly a p pl i e d re f e re nc e vo lt age. t h e i n put s p a n o f t h e a d c t r acks r e fer e nce v o l t a g e cha n g e s lin e a r ly . the va r i o u s r e fer e n c e m o des a r e su mma r i z e d a nd des c r i b e d in t h e fol l o w in g s e c t io n s . t a b l e 8 t a b l e 8 ta ble 8. r e fere nce co nfi g ura t i o n sum m a r y i f th e a d c i s b e i n g d r i v en d i f f e r e n ti all y th r o u gh a tra n s f o r m e r , t h e r e fer e n c e v o l t a g e ca n b e us e d t o b i as t h e cen t er t a p (co m - mo n - mo d e vo lt age ) . internal reference connection a co m p a r a t o r wi t h in t h e ad9 245 det e c t s t h e p o t e n t ial a t t h e s e ns e pin and co nf igur es t h e refer e n c e i n t o one o f fo ur p o s s i b l e st a t es, w h ich a r e s u mma r ize d i n . i f s e ns e is g r o u n d e d , t h e refer e n c e am plif i e r sw i t ch is c o nn e c te d t o t h e in t e r n al r e sis t o r di vider (s e e ) , s e t t in g vref t o 1 v . c o nn e c t i n g t h e s e ns e pin t o v r ef sw i t ch es t h e r e fer e n c e a m p l i f i e r o u t p u t t o th e s e n s e p i n , co m p le ti n g th e loo p a n d prov i d i n g a 0 . 5 v re f e re nc e output . i f a re s i stor d i v i d e r i s co nne c t e d as sho w n i n , t h e s w i t ch is aga i n s et to t h e s e ns e pin. this p u ts t h e r e fer e n c e a m plif ier i n a n o ni n v er t i n g m o de wi t h the vref o u t p u t def i n e d as f o l l o w s: f i g u r e 3 3 f i gure 33. inte rn al r e fer e n c e configu r atio n f i gur e 3 5 ? ? ? ? ? ? + = 1 5 . 0 i n a l l r e fer e n c e co nf igur a t io n s , ref t an d ref b dr i v e t h e a / d co n v ersio n co r e a nd es t a b l is h i t s in p u t s p a n . the in p u t ra n g e o f t h e ad c alwa ys e q uals t w ic e t h e v o l t a g e a t t h e r e fer e n c e p i n fo r ei t h er a n i n t e r n al o r a n ext e r n al r e fer e n c e . 03583-b-017 10 i f th e in t e r n al ref e r e n c e o f the AD9245 is us ed t o dr i v e m u l t i p le c o n v e r te r s to i m prove g a i n m a tch i n g , t h e l o a d i n g of t h e re f e r- en c e b y t h e o t her co n v er t e rs m u s t b e con s ider e d . f i gur e 34 d e p i ct s h o w th e i n t e rn al r e f e r e n c e v o l t a g e i s a f f e ct ed b y loa d i n g . load (ma) e rror (%) 0.05 0 0.5 1.0 1.5 2.0 2.5 3.0 0358 3-b -019 0 0.25 0.20 0.15 0.10 0.05 0.5v error (%) 1.0v error (%) f i g u re 34. v r e f ac cur a c y v s . l oad selected mode sense voltage internal switch position resulting vref (v) resulting di ffe rential span (v p-p) external reference avdd n/a n/a 2 external reference internal fixed reference vref sense 0.5 1.0 programmable reference 0.2 v to v r ef sense ? ? ? ? ? ? + 1 5 . 0 (see figure 35) 2 vref internal fixed reference agnd to 0.2 v internal divider 1.0 2.0 rev. b page 17 of 28
AD9245 03583-b-018 10 external r e ference operation the us e o f a n e x t e r n al r e fer e n c e ma y b e n e ces s a r y t o enha n c e t h e ga i n acc u rac y o f t h e ad c o r im p r o v e t h er mal dr if t cha r ac - t e r i s t ics. w h en m u l t i p le ad cs t r ack o n e an o t her , a sin g le re f e re nc e ( i n t e r n a l or e x te r n a l ) m a y b e ne c e ss a r y to re d u c e g a i n ma t c hin g er r o r s t o a n accep t a b l e lev e l . f s h o w s t h e typ i - cal dr if t cha r ac ter is t i cs o f t h e i n t e r n al r e fer e n c e in b o t h 1.0 v a nd 0.5 v m o de s. i gur e 3 6 f i g u re 36. t y pic a l v r e f d r if t w h en t h e s e nse p i n is t i e d t o a v d d , t h e i n te r n al r e fer e n c e is dis a b l e d , al lo wi n g t h e us e o f a n ext e r n al r e fer e n c e . a n i n t e r n al r e fer e n c e b u f f er lo ads t h e ext e r n al r e fer e n c e wi t h a n e q ui vale n t 7 k lo ad . the i n t e r n al b u f f er s t i l l g e n e r a t e s t h e p o si t i v e and n e g a t i ve f u l l -s c a le r e fer e n c es, r e ft an d refb , fo r t h e ad c co r e . the in p u t s p a n is alw a ys t w ice t h e val u e of t h e r e fer e n c e v o l t a g e t h er efo r e , t h e ext e r n al refer e n c e m u s t b e limi t e d t o a maxim u m o f 1.0 v . temperature (c) vr ef er r o r ( ) 40 0 1.0 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 80 70 60 50 40 30 20 10 0 1 0 2 0 30 03583-b-040 vref = 0.5v vref = 1.0v operational mode se lection a s di s c us s e d e a rlier , t h e ad924 5 ca n o u t p ut da t a i n ei t h er o f fs et b i na r y o r tw os co m p le m e n t fo rma t . ther e is als o a p r o v isio n fo r ena b lin g o r dis a b l in g t h e clo c k d u ty c y cle s t ab i l izer (d c s ). the m o d e p i n i s a m u l t ilev e l in p u t th a t co n t r o ls th e da t a f o rm a t a nd d c s st a t e. the i n p u t t h r e sh old va l u es and co r r esp o n d in g m o d e s e le c t ion s a r e o u t l ine d i n . t a b l e 9 table 9. mod e selection mo de vo ltage data format duty cycle stabilizer a v d d t w o s complem e n t d i s a b l e d 2/3 avdd twos complement enabled 1/3 avdd offset binary enabled agnd (defa u lt) offset binary disabled evaluation board the AD9245 e v al ua t i o n bo a r d p r o v ides al l o f th e su p p o r t cir c ui t r y r e q u ir e d t o o p er a t e t h e ad c in i t s v a r i o u s m o des and co nf igur a t io n s . c o m p lete s c h e ma t i cs and l a yo u t plo t s fol l o w a nd de m o n s t r a te t h e p r o p er r o u t i n g and g r o u ndin g te chni q u es t h a t sh o u ld be a p p l ie d a t t h e syst em l e v e l . i t is cr i t ical tha t sig n al s o ur ces wi t h v e r y lo w p h as e n o is e (1 p s r m s ji t t er) b e us e d t o r e ali z e t h e u l t i ma te p e r f o r ma nce o f t h e co n v er t e r . p r o p er f i l t er in g o f t h e in p u t sig n al, to r e m o v e ha r m o n ics a nd l o w e r t h e in t e g r a t e d n o is e a t t h e in p u t, is a l s o n e ce ss a r y t o achie v e t h e sp e c if ie d n o is e p e r f o r ma nce . the AD9245 can b e dr i v en sin g le-ende d o r dif f er en tial l y t h rou g h a t r ans f or me r . s e p a r a te p o we r pi ns are prov i d e d to is ola te t h e d u t f r o m t h e s u p p or t cir c ui t r y . e a c h in p u t co nf igu - ra ti o n ca n b e se lect ed b y p r o p er co n n ecti o n o f v a ri o u s j u m p e r s (r efer t o t h e s c hema t i cs). an al t e r n a t i v e dif f er en tial a n alo g in p u t p a th usin g a n ad8351 o p a m p is i n cl u d e d i n t h e l a yo ut, b u t is n o t p o pu la t e d i n p r o - d u cti o n . de s i g n e r s i n t e r e s t ed in ev al ua tin g t h e o p a m p w i t h th e ad c sh o u ld r e m o v e c15, r12, a nd r3, an d p o p u la te t h e o p a m p cir c ui t. the p a s s i v e n e tw ork betw e e n t h e ad8351 o u t p u t s a nd t h e ad924 5 al lo ws t h e us er t o o p t i mi ze t h e f r e q uen c y re sp ons e of t h e op am p f o r t h e a p pl i c a t i o n . rev. b | page 18 of 28
AD9245 03583-b-050 123 45 6 p1 3 p1 4 x f ri n1 opti onal xfr t2 ft c1 113 nc ct 1 t 1 adt1 1wt 6 2 34 5 1 2 3 4 5 r s i ngle e nde d r18 25 ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? f i g u re 37. lfcs p ev al uat i on bo ar d s c h e m a t i c a n a l og i n put s and du t rev. b | page 19 of 28
AD9245 03583-b - 051 drx d 13x gnd d2 x d1 x gnd d0 x d 11x d 12x dr v d d d 10x d9 x gnd d8 x d7 x d5 x d6 x gnd d4 x d3 x drv dd 2c lk 2d b 2d 7 gnd 2d 6 2d 5 1d 2 1d 1 1c lk 2d 4 v cc v cc 2d 3 gnd 2d 2 2d 1 1d 7 1d 6 1d 5 1d 8 gnd 1d 4 1d 3 gnd 2oe 2b 27 26 25 12 11 1oe 24 23 gnd gnd 22 21 18 17 16 15 g n d v cc v cc 1 4 1 3 g n d 2 5 2 6 2 7 2 8 2 9 3 0 3 1 3 2 3 3 3 4 3 5 3 6 3 7 3 8 3 9 4 0 4 1 4 2 4 3 4 4 4 5 4 6 4 7 4 8 2 4 2 3 2 2 2 1 2 0 1 9 1 8 1 7 1 6 1 5 1 4 1 3 1 2 1 1 1 0 9 8 7 6 5 4 3 2 1 i n o u t c l k a t / d a c 1 u 1 7 4 l v t h 1 6 2 3 7 4 c l k l a t / d a c g n d g n d d r v d d g n d g n d d r v d d g n d g n d d r y m s b l s b 2 4 6 8 1 0 1 2 1 4 1 6 1 8 2 0 2 2 2 4 2 6 2 8 3 0 3 2 3 4 3 6 3 8 4 0 2 4 6 8 1 0 1 2 1 4 1 6 1 8 2 0 2 2 2 4 2 6 2 8 3 0 3 2 3 4 3 6 3 8 4 0 1 3 5 7 9 1 1 1 3 1 5 1 7 1 9 2 1 2 3 2 5 2 7 2 9 3 1 3 3 3 5 3 7 3 9 1 3 5 7 9 1 1 1 3 1 5 1 7 1 9 2 1 2 3 2 5 2 7 2 9 3 1 3 3 3 5 3 7 3 9 g n d d r g n d m s b d r y g n d a m p i n a m p i n b g n d v a m p g n d g n d g n d g n d v a m p g n d v a m p g n d g n d h e a d e r 4 0 c 2 7 0 . 1 ? ? ? ? ? ? ? ? ? ? ? f i g u re 38. lfcs p ev al uat i on bo ar d s c h e m a t i c d i g i t a l p a t h rev. b | page 20 of 28
AD9245 03583-b-052 c10 22 ? ? ? ? ? ? ? ? ? ? ? ? ? rev. b | page 21 of 28
AD9245 03583-b-053 f i g u re 40. lfcs p ev al uat i on bo ar d lay o ut , p r i m ar y s i de 03583-b-054 f i g u re 41. lfcs p ev al uat i on bo ar d lay o ut , s e c o ndar y sid e 03583-b-055 f i g u re 42. lfcs p ev al uat i on bo ar d lay o ut , g r ound p l ane 03583-b-056 f i g u re 43. lfcs p ev al uat i on bo ar d lay o ut , p o we r p l ane rev. b | page 22 of 28
AD9245 03583-b-057 f i g u re 44. lfcs p ev al uat i on bo ar d lay o ut , p r i m ar y s i lk s c reen 03583-b-058 f i g u re 45. lfcs p ev al uat i on bo ar d lay o ut , s e c o ndar y si lk s c r e en rev. b | page 23 of 28
AD9245 table 10. lfcs p ev aluation b o ard bill of ma terials item ty . o m i t 1 r e f e r e n c e desi g n a t o r device p a c k a g e v a l u e recommended vendorpart number supplied by adi 1 8 c1, c5, c7, c8, c 9 , c11, c12, c13, c15, c16, c 31, c33, c34, c36, c37, c41, c 43, c47 1 8 c6, c18, c27, c1 7, c28, c35, c45, c 44 chip capacitor 0603 0.1 f 8 c2, c3, c4, c10, c20, c22, c25, c29 2 2 c46, c 2 4 tantalum capacitor tajd 10 f 3 8 c14, c30, c32, c 38, c39, c40, c48, c 49 chip capacitor 0603 0.001 f 4 3 c19, c21, c23 chip capacitor 0603 10 pf 5 1 c26 chip capacitor 0603 10 pf 9 e31, e35, e43, e4 4, e50, e51, e52, e53 6 2 e 1 , e 4 5 header ehole jumper blocks 7 2 j1, j2 sma connector50 sma 8 1 l 1 i n d u c t o r 0 6 0 3 1 0 n h coilcraft0603c s- 10ngbu 9 1 p2 terminal block tb6 ieland25.602. 2653.0, 5-530-0625-0 10 1 p12 header dual 20-pin rt angle header40 digi-ey s2131-20-nd 5 r3, r12, r2 3, r2 8, rx 11 6 r16, r17, r22, r27, r42, r37 chip resistor 0603 0 12 2 r4, r15 chip resistor 0603 33 1 3 1 4 r5, r6, r7, r8, r 13, r20, r21, r24, r25, r26, r30, r31, r32, r36 chip resistor 0603 1 k 14 2 r10, r11 chip resistor 0603 36 1 r 2 9 15 1 r 1 9 chip resistor 0603 50 16 2 rp1, rp2 resistor pack r742 220 digi-ey cts742c16322 0jtr 17 1 t1 adt1-1t at1-1t mini-circuits 18 1 u1 74lvth1623 74 cmos register tssop-48 19 1 u4 AD9245bcp ad c (dut) csp-32 analog device s, inc. 20 1 u5 74vc86m soic-14 fairchild 21 1 pcb ad92bcppc b pcb analog devices, inc. 22 1 u3 ad8351 op amp msop-8 analog device s, inc. 23 1 t2 macom transformer etc1-1-13 1 -1 t macometc1-1 -13 24 5 r1, r2, r9, r38, r39 chip resistor 0603 select 25 3 r14, r18, r35 chip resistor 0603 25 26 2 r40, r41 chip resistor 0603 10 k 27 1 r34 chip resistor 1.2 k 28 1 r33 chip resistor 100 total 82 34 1 th ese it ems ar e in clud ed in t h e p c b d e s i gn, but are omitted at ass e mbl y. rev. b page 24 of 28
AD9245 outline dimensions compliant to jedec standards mo-220-vhhd-2 0.30 0.23 0.18 0. 2 0 r e f 0. 80 m a x 0.65 typ 0.05 max 0.02 nom 12 max 1.00 0.85 0.80 seating plane coplanarity 0.08 1 32 8 9 25 24 16 17 bottom view 0.50 0.40 0.30 3.50 ref 0.50 bsc 3.25 3.10 sq 2.95 0.60 max 0.60 max 0. 25 m i n top view pin 1 indicator pin 1 indicator 5.00 bsc sq 4.75 bsc sq f i gure 46. 3 2 -l ead f r a m e chip s c a l e p a ckage [lfcs p ] (c p - 3 2 - 1 ) di me nsio ns sho w n i n mi ll im e t e r s ordering guide ad92 45 prod ucts temperature r a nge package descri ption package outlin e AD9245bcp-80 1 40c to 85c lead frame chip scale package (lfcsp) cp-32-1 AD9245bcprl7 80 1 40c to 85c lead frame chip scale package (lfcsp) cp-32-1 AD9245bcp-8 0 1, 2 40c to 85c lead frame chip scale package (lfcsp) cp-32-1 AD9245bcprl 7 -80 1, 2 40c to 85c lead frame chip scale package (lfcsp) cp-32-1 AD9245bcp-80e b 1 e v a l u a t i o n bo ar d 1 it i s recom m e n d ed t h a t t h e epose d p a ddl e be s o l d er ed t o t h e gr oun d p l a n e fo r t h e lf cs p pa ck a g e. th ere i s a n i n crea se d r e li a b i l i ty of the s o l d e r o ints , an d the mai- mum thermal capabil i ty of the package is achieved with t h e epo se d pad d l e sol d er ed t o t h e c u s t omer board . 2 = lea d fr ee. rev. b page 25 of 28
AD9245 notes rev. b | page 26 of 28
AD9245 notes rev. b | page 27 of 28
AD9245 notes ? 2003 a n alo g devic e s, inc. all rig h ts res e rve d . t r ade m arks a n d re g i s - tered trade m arks are the property of their respective owners . c03583-0-10/03( b) rev. b | page 28 of 28

▲Up To Search▲

Price & Availability of AD9245

	To Download AD9245 Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .