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3 nv/hz ultralow distortion, high speed op amp ad8045 rev. a 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 ? 2004 analog de vices, i n c. al l r i ght s r e ser v ed . features ultralow d istortion sfdr ?101 dbc @ 5 mhz ?90 dbc @ 20 mhz ?63 dbc @ 70 mhz third-o r der int e rcept 43 dbm @ 10 m hz low noise 3 nv/h z 3 pa/hz high speed 1 gh z, ?3 db b a ndwidth (g = +1) 1350 v/s slew rate 7.5 ns sett ling t i me to 0.1% standard and l o w disto r tio n pino ut supply current : 15 ma offset voltage: 1.0 mv m a x wide s u pply voltage range: 3. 3 v to 1 2 v applic ati o ns instrumentation if and baseban d amplifiers active fi lters adc driv ers dac bu ffers connection diagram s 1 2 5 6 7 8 nc feedbac k ?in +in +v s output nc ?v s 3 4 04814-0-001 f i g u re 1. 8-l e ad a d 80 45 lfcs p (c p - 8) 04814-0-001 1 f eedb a c k 2 ?in 3 +in ?v s 4 8 + v s nc 7 output nc 6 5 f i g u re 2. 8-l e ad a d 80 45 soic/e p (r d - 8) general description the ad8045 is a uni t y ga in s t ab le v o l t a g e f eedbac k am p l if ier w i t h u l t r a l ow d i stor t i on , l o w no i s e, an d h i g h sl e w r a te. w i t h a s p ur io us-f r e e d y na mic ra n g e o f ?90 db c @ 20 mh z, t h e ad8045 is an ideal s o l u tio n in a va r i ety o f a p p l ica t ion s , in cl u d in g u l t r a s o u nd , a t e, ac t i ve f i l t ers, a nd a d c dr i v ers. a d i s propr i e t a r y ne x t ge ne r a t i on x f c b pro c e s s a n d i n nov a t i v e archi t e c t u re enabl e s su ch hig h p e r f o r manc e am pl if iers . the ad8045 f e a t ur es a lo w dis t o r tio n p i n o u t f o r th e lfcs p , w h i c h i m prove s s e c o n d h a r m on i c d i stor t i on a n d s i m p l i f i e s t h e la yo u t o f the cir c ui t bo a r d . the ad8045 has 1 gh z ban d wid t h, 1350 v/s slew ra t e , an d s e t t les t o 0.1 % in 7.5 n s . w i th a wide s u p p l y v o l t a g e ra n g e (3.3 v t o 12 v) a nd lo w o f fs et v o l t a g e (200 v), th e ad8045 is a n ide a l can d i d a t e fo r sys t em s t h a t r e q u i r e hig h dyna mi c ra n g e , p r e c i- sio n , a nd hig h sp e e d . the ad8045 am p l if ier is a v ail a b l e in a 3 mm 3 mm lfcs p a nd t h e st an d a r d 8-le ad soi c . b o t h p a ck a g es fe a t ur e an exp o s e d p a ddle t h a t p r o v ides a l o w t h er mal r e sis t an ce p a t h t o t h e pc b . this e n a b les m o r e ef f i cien t h e a t t r a n sfer , a n d i n cr e a s e s r e liab ili t y . th e ad8045 w o rks o v er th e ext e nded ind u s t r i al t e m p era t ur e ra ng e (?40c t o +125c). 04814-0-079 frequency (mhz) 100 0.1 1 1 0 harm oni c di storti on (dbc) ?20 ?30 ?40 ?50 ?60 ?70 ?80 ?90 ?100 ?120 ?110 hd3 lfcsp hd2 lfcsp g = +1 v s = 5 v v out = 2v p-p r l = 1k ? r s = 100 ? f i g u re 3. ha rm on ic d i s t o r t i on v s . f r eq uenc y f o r v a ri ous p a ckag es
ad8045 rev. a | page 2 of 24 table of contents specifications with 5 v supply ..................................................... 3 specifications with +5 v supply ..................................................... 4 absolute maximum ratings ............................................................ 5 thermal resistance ...................................................................... 5 esd caution .................................................................................. 5 pin configurations and function descriptions ........................... 6 typical performance characteristics ............................................. 7 circuit configurations ................................................................... 16 wideband operation ................................................................. 16 theory of operation ...................................................................... 17 frequency response ................................................................... 17 dc errors .................................................................................... 17 output noise ............................................................................... 18 applications ..................................................................................... 19 low distortion pinout ............................................................... 19 high speed adc driver ........................................................... 19 90 mhz active low-pass filter (lpf) ..................................... 20 printed circuit board layout ....................................................... 22 signal routing ............................................................................. 22 power supply bypassing ............................................................ 22 grounding ................................................................................... 22 exposed paddle ........................................................................... 23 driving capacitive loads .......................................................... 23 outline dimensions ....................................................................... 24 ordering guide .......................................................................... 24 revision history 9/04data sheet changed from rev. 0 to rev. a changes to features......................................................................... 1 changes to specifications ............................................................... 4 changes to figure 58..................................................................... 15 changes to figure 63..................................................................... 17 changes to frequency response section ................................... 17 changes to figure 64..................................................................... 17 changes to dc errors section..................................................... 17 changes to figure 65..................................................................... 17 changes to figure 66..................................................................... 18 changes to output noise section ............................................... 18 changes to ordering guide ......................................................... 24 7/04revision 0: initial version
ad8045 rev. a | page 3 of 24 specifications with 5 v supply t a = 25c, g = +1, r s = 100 ?, r l = 1 k? to ground, unless noted otherwise. exposed paddle must be floating or connected to ?v s . table 1. parameter conditions min typ max unit dynamic performance C3 db bandwidth g = +1, v out = 0.2 v p-p 1000 mhz g = +1, v out = 2 v p-p 300 350 g = +2, v out = 0.2 v p-p 320 400 mhz bandwidth for 0.1 db flatness g = +2, v out = 2 v p-p, r l = 150 ? 55 mhz slew rate g = +1, v out = 4 v step 1000 1350 v/s settling time to 0.1% g = +2, v out = 2 v step 7.5 ns noise/harmonic performance harmonic distortion (dbc) hd2/hd3 f c = 5 mhz, v out = 2 v p-p lfcsp ?102/?101 dbc soic ?106/?101 dbc f c = 20 mhz, v out = 2 v p-p lfcsp ?98/?90 dbc soic ?97/?90 dbc f c = 70 mhz, v out = 2 v p-p lfcsp ?71/?71 dbc soic ?60/?71 dbc input voltage noise f = 100 khz 3 nv/hz input current noise f = 100 khz 3 pa/hz differential gain error ntsc, g = +2, r l = 150 ? 0.01 % differential phase error ntsc, g = +2, r l = 150 ? 0.01 degrees dc performance input offset voltage 0.2 1.0 mv input offset voltage drift see figure 54 8 v/c input bias current 2 6.3 a input bias current drift 8 na/c input bias offset current 0.2 1.3 a open-loop gain v out = ?3 v to +3 v 62 64 db input characteristics input resistance common-mode/differential 3.6/1.0 m? input capacitance common-mode 1.3 pf input common-mode voltage range 3.8 v common-mode rejection v cm = 1 v ?83 ?91 db output characteristics output overdrive recovery time v in = 3 v, g = +2 8 ns output voltage swing r l = 1 k? ?3.8 to +3.8 ?3.9 to +3.9 v r l = 100 ? ?3.4 to +3.5 ?3.6 to +3.6 v output current 70 ma short-circuit current sinking/sourcing 90/170 ma capacitive load drive 30% overshoot, g = +2 18 pf power supply operating range 1.65 5 6 v quiescent current 16 19 ma positive power supply rejection +v s = +5 v to +6 v, ?v s = ?5 v ?61 ?68 db negative power supply rejection +v s = +5 v, ?v s = ?5 v to ?6 v ?66 ?73 db
ad8045 rev. a | page 4 of 24 specifications with +5 v supply t a = 25c, g = +1, r s = 100 ?, r l = 1 k? to midsupply, unless otherwise noted. exposed paddle must be floating or connected to ?v s . table 2. parameter conditions min typ max unit dynamic performance C3 db bandwidth g = +1, v out = 0.2 v p-p 900 mhz g = +1, v out = 2 v p-p 160 200 mhz g = +2, v out = 0.2 v p-p 320 395 mhz bandwidth for 0.1 db flatness g = +2, v out = 2 v p-p, r l = 150 ? 60 mhz slew rate g = +1, v out = 2 v step 480 1060 v/s settling time to 0.1% g = +2, v out = 2 v step 10 ns noise/harmonic performance harmonic distortion (dbc) hd2/hd3 f c = 5 mhz, v out = 2 v p-p lfcsp ?89/?83 dbc soic ?92/?83 dbc f c = 20 mhz, v out = 2 v p-p lfcsp ?81/?70 dbc soic ?83/?70 dbc f c = 70 mhz, v out = 2 v p-p lfcsp ?57/?46 dbc soic ?57/?46 dbc input voltage noise f = 100 khz 3 nv/hz input current noise f = 100 khz 3 pa/hz differential gain error ntsc, g = +2, r l = 150 ? 0.01 % differential phase error ntsc, g = +2, r l = 150 ? 0.01 degrees dc performance input offset voltage 0.5 1.4 mv input offset voltage drift see figure 54 7 v/c input bias current 2 6.6 a input bias current drift 7 na/c input bias offset current 0.2 1.3 a open-loop gain v out = 2 v to 3 v 61 63 db input characteristics input resistance common-mode/differential 3/0.9 m? input capacitance common-mode 1.3 pf input common-mode voltage range 1.2 to 3.8 v common-mode rejection v cm = 2 v to 3 v ?78 ?94 db output characteristics output overdrive recovery time v in = ?0.5 v to +3 v, g = +2 10 ns output voltage swing r l = 1 k? 2.2 to 3.7 1.1 to 4.0 v r l = 100 ? 2.5 to 3.5 1.2 to 3.8 v output current 55 ma short-circuit current sinking/sourcing 70/140 ma capacitive load drive 30% overshoot, g = +2 15 pf power supply operating range 3.3 5 12 v quiescent current 15 18 ma positive power supply rejection +v s = +5 v to +6 v, ?v s = 0 v ?65 ?67 db negative power supply rejection +v s = +5 v, ?v s = 0 v to ?1 v ?70 ?73 db
ad8045 r e v. a | pa ge 5 o f 2 4 absolute maximum ra tings table 3. p a r a m e t e r r a t i n g supply voltage 12.6 v power dissi pati on see figure 4 common-mode input vol t age ? v s ? 0.7 v to +v s + 0.7 v differential input voltage v s exposed paddle voltage ?v s storage temperature ?65c to +125c operating tem p erature range ?40c to +125c lead temperature range (sol dering 10 s e c) 300c junction tempe r ature 150c 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 r a t i ng o n ly ; f u nc t i on a l op e r a t i o n of t h e d e v i c e a t t h e s e or a n y o t h e r con d i t io ns a b o v e t h o s e i ndic a te d i n t h e op er a t io na l 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 resist ance 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, i . e. , ja is sp e c if ie d f o r d e v i ce so l d er ed i n ci r c ui t boa r d f o r s u rfa c e - m o un t pa c k a g es . table 4. therm a l resistance package type ja jc unit s o i c 8 0 3 0 c / w l f c s p 9 3 3 5 c / w maximum power dissipation the maxim u m s a f e p o w e r dis s i p a t io n f o r the ad8045 is limi t e d b y t h e ass o ci a t e d r i s e in j u n c t i on t e m p er a t ur e ( t j ) o n t h e die . a t a pprox i m a t el y 1 5 0 c, w h ich is t h e g l ass t r an si t i o n t e m p er a t ur e , t h e p r o p er t i es of t h e plas t i c chan g e . e v en t e m p o r a r i l y e x ce e d ing t h is t e m p era t ur e limi t ma y chan g e t h e s t r e s s es t h a t t h e p a cka g e e x e r t s o n th e d i e , pe rm a n en tl y s h i f ti n g th e pa ra m e tri c pe rf o r m - a n c e o f th e ad8 045. e x ceedin g a j u n c tion t e m p era t ur e o f 175 c fo r a n ex tende d p e r i o d of t i m e ca n r e su lt in cha n ges in si lico n d e v i ces, p o t e n t ia l l y c a usin g deg r a d a t ion o r loss o f fu n c ti o n ali t y . the p o w e r dis s i p a t e d in t h e p a cka g e (p d ) i s th e s u m o f th e q u i - es cen t p o w e r dissi p a t ion and t h e p o w e r dissi p a t e d i n t h e die d u e t o t h e ad8 045 dr i v e a t t h e o u t p u t . th e q u ies c en t p o w e r is t h e v o l t a g e b e t w e e n t h e su p p l y p i n s (v s ) tim e s th e q u i e sce n t cu rr e n t ( i s ). p d = qu i e sc e n t p o w e r + ( to t a l d r i v e p o w e r C lo a d p o w e r ) () l 2 out l out s s s d r v C r v 2 v i v p ? ? ? ? ? ? ? ? + = r m s output vo lt age s s h ou l d b e c o ns i d e r e d . i f r l i s re f e re nc e d t o ? v s , as in sin g le -su p ply o p er a t i o n, t h e t o t a l dr iv e p o w e r is v s i ou t . i f th e r m s sig n al le v e l s a r e indet e r m ina t e , co n s ider th e worst c a s e , w h e n v ou t = v s /4 fo r r l to mi dsupp l y . () ( ) l s s s d r / v i v p 2 4 + = in s i n g l e - s u p p l y o p e r at i o n w i t h r l re f e re nc e d to ? v s , w o r s t c a s e is v ou t = v s /2. air f l o w in cr eas e s h e a t dis s i p a t io n, ef f e c t i v e l y r e d u cin g ja . als o , m o r e met a l dir e c t l y in con t ac t wi th t h e p a c k a g e leads and e x p o s e d p a d d l e f rom me t a l t r a c e s , t h rou g h ho l e s , g rou nd, a n d p o w e r p l a n es r e d u ce ja . f i g u re 4 show s t h e m a x i m u m s a f e p o we r d i ss ip a t i o n i n t h e p a cka g e v e rs us t h e am b i e n t t e m p era t ur e fo r t h e exp o s e d p a ddle so i c (80c/ w) a n d lfcs p (93 c/ w) p a cka g e o n a jed e c st andard 4 - l a ye r b o ard. ja val u es a r e a p p r o x ima t io n s . 04814-0-080 ambient temperature (c) 120 ?40 ? 20 0 2 0 4 0 6 0 8 0 100 m a xim u m pow e r d i ssipa tion ( w at t s ) 0.0 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 lfcsp soic f i g u re 4. m a x i m u m p o wer d i s s i pat i on v s . t e mpe r at u r e f o r a 4-laye r b o a r d esd c a ution esd (electrostatic discharge) sensitive device. ele c tr ostatic charg e s as high as 4000 v readily accumulate on the human body and test eq uipment and can discharg e wit h out detection. althou gh this product features proprietary esd protection circu i try, permanent damage may occur on devices s u bjec ted to high energy elec- trostatic dischar g es. t h erefore, proper esd prec aution s are reco mmended to avoid performanc e degradation and loss of functionality.
ad8045 r e v. a | pa ge 6 o f 2 4 pin conf igura t ions and f u ncti on descriptions 04814-0-003 feedback 8 ?i n 7 +in 6 ?v s 5 nc 1 +v s 2 output 3 nc 4 nc = no connect ad8045 bottom view (not to scale) f i gure 5. soic p i n configur ation 04814-0-004 bottom view (not to scale) 8 7 6 54 3 2 1 nc feedback ?in +in +v s output nc ?v s nc = no connect f i g u re 6 . 8-l e ad l f csp pin conf ig u r at ion n o t e : the exp o s e d p a ddle m u st b e conn e c t e d to ?v s o r i t m u s t be e l ec tr ical l y is ola t ed (f lo a t ing). table 5. 8- lead soic pin fu n c tion descriptions pin no. mnemonic description 1 f e e d b a c k f e e d b a c k p i n 2 ? i n i n v e r t i n g i n p u t 3 + i n n o n i n v e r t i n g in p u t 4 ? v s negative supply 5 n c n c 6 o u t p u t o u t p u t 7 + v s positive supply 8 n c n c 9 e x p o s e d p a d d l e must be connected to ?v s or electrically isola t ed ta ble 6. 8- lea d lf csp pi n f u nct i on d e s c ri pt i o ns pin no. mnemonic description 1 n c n o c o n n e c t 2 f e e d b a c k f e e d b a c k p i n 3 ? i n i n v e r t i n g i n p u t 4 + i n n o n i n v e r t i n g in p u t 5 ? v s negative supply 6 n c n o c o n n e c t 7 o u t p u t o u t p u t 8 + v s positive supply 9 e x p o s e d p a d d l e must be connected to ?v s or electrically isola t ed
ad8045 r e v. a | pa ge 7 o f 2 4 typical perf orm ance cha r acte ristics 04814-0-049 frequency (mhz) 1000 1 1 0 100 normalize d clos e d -loop gain (db) 1 0 ?1 ?2 ?3 ?4 ?5 ?6 ?7 g = +2 g = ? 1 g = +10 v s = 5 v r l = 1k ? f i gur e 7 . sm al l si g n a l f r equenc y resp o n se f o r v a ri o u s g a i n s 04814-0-050 frequency (mhz) 1000 10 100 closed- l oop gain ( d b) 4 3 2 1 0 ?1 ?3 ?2 ?4 ?5 ?6 g = +1 v s = 5 v r s = 100 ? r l = 500 ? r l = 100 ? r l = 1k ? f i g u re 8. s m a l l sig n al f r equenc y r e s p ons e f o r v a r i ous l o ads 04814-0-051 frequency (mhz) 1000 10 100 closed- l oop gain ( d b) 5 4 3 2 0 1 ?2 ?1 ?3 ?4 ?5 v s = 5v v s = 2.5v g = +1 r l = 1k ? r s = 100 ? f i g u re 9. s m a l l sig n al f r equenc y r e s p ons e f o r v a r i ous s u p p li es 04814-0-048 frequency (mhz) 1000 10 100 closed- l oop gain ( d b) 12 10 11 8 9 6 7 4 5 2 3 0 1 18pf 5pf 10pf g = +2 v s = 5 v r l = 1k ? r f = 499 ? 0pf f i g u re 10. sm a ll s i g n al f r equenc y r e s p ons e f o r v a r i ous capa cit i ve l oads 04814-0-052 frequency (mhz) 1000 10 100 closed- l oop gain ( d b) 4 2 0 ?1 ?3 3 1 ?2 ?4 ?5 ?6 ?4 0 c +25 c +125 c g = +1 v s = 5 v r l = 1k ? f i g u re 11. sm a ll s i g n al f r equenc y r e s p ons e f o r v a r i ous t e mper at ur es 04814-0-039 frequency (mhz) 1 1 0 100 closed- l oop gain ( d b) 6.3 6.2 6.1 6.0 5.9 5.8 5.7 v out = 2v p-p v out = 200mv p-p g = +2 v s = 5 v r f = 499 ? r l = 150 ? f i g u re 12. 0. 1 db f l at nes s v s . f r equ e nc y f o r v a ri ous o u t p u t v o lt ag es
ad8045 r e v. a | pa ge 8 o f 2 4 04814-0-043 frequency (mhz) 1000 10 100 closed- l oop gain ( d b) 2 0 1 ?2 ?1 ?4 ?3 ?6 ?5 ?8 ?7 ?10 ?9 g = +1 r l = 1k ? r s = 100 ? v out = 2v p-p v s = 2.5v v s = 5 v f i g u re 13. lar g e s i g n al f r equenc y r e s p ons e f o r v a r i ous s u p p l i es 04814-0-042 frequency (mhz) 1000 10 100 closed- l oop gain ( d b) 2 0 1 ?2 ?1 ?4 ?3 ?6 ?5 ?8 ?9 ?7 ?10 g = +1 v s = 5v r s = 100 ? v out = 2v p-p r l = 1k ? r l = 100 ? f i g u re 14. lar g e s i g n al f r equenc y r e s p ons e f o r v a r i ous l oads 04814-0-041 frequency (mhz) 1000 1 1 0 100 normalize d clos e d -loop gain (db) 2 1 0 ?1 ?2 ?3 ?4 ?5 ?6 ?7 ?8 v s = 5v r f = 499 ? r l = 1k ? v out = 2v p-p g = +10 g = ? 1 g = +2 f i gur e 1 5 . la r g e signa l f r equenc y r e sp o n se f o r v a ri o u s g a i n s 04814-0-064 frequency (mhz) 1000 0.01 0.1 1 1 0 100 open - l oop ph a se ( d egrees) ?360 0 ?90 ?135 ?180 ?45 ?225 ?270 ?315 open- l oop gain ( d b) 70 50 60 40 20 30 10 0 ?10 v s = 5 v r l = 1k ? f i gure 16. o p en-l oop g a in and phase vs . f r equenc y 04814-0-030 frequency (mhz) 100 0.1 1 1 0 harmonic dis t ortion (dbc ) ?20 ?30 ?40 ?50 ?60 ?70 ?80 ?90 ? 100 ? 110 ? 120 hd3 soic and lfcsp hd2 lfcsp hd2 soic g = +1 v s = 5 v v out = 2v p-p r l = 1k ? r s = 100 ? f i gur e 1 7 . ha rm onic di stor ti on vs . f r eque nc y fo r v a r i o u s p a c k a g e s 04814-0-028 frequency (mhz) 0.1 1 1 0 100 harmonic dis t ortion (dbc ) ?30 ?40 ?50 ?60 ?70 ?80 ?90 ? 100 ? 110 ? 120 g = +1 v s = 5 v v out = 4v p-p r l = 1k ? hd3 lfcsp and soic hd2 lfcsp hd2 soic f i gur e 1 8 . ha rm onic di stor ti on vs . f r eque nc y fo r v a r i o u s p a c k a g e s
ad8045 r e v. a | pa ge 9 o f 2 4 04814-0-032 frequency (mhz) 0.1 1 1 0 100 harmonic dis t ortion (dbc ) ?20 ?30 ?40 ?50 ?60 ?70 ?80 ?90 ? 100 ? 110 g = +1 v s = 5 v v out = 2v p-p r l = 100 ? r s = 100 ? hd2 soic hd2 lfcsp hd3 soic and lfcsp f i gur e 1 9 . ha rm onic di stor ti on vs . f r eque nc y fo r v a r i o u s p a c k a g e s 04814-0-036 frequency (mhz) 0.1 1 1 0 100 harmonic dis t ortion (dbc ) ?20 ?30 ?40 ?50 ?60 ?70 ?80 ?90 ? 100 ? 110 g = ? 1 v s = 5 v v out = 2v p-p r l = 1k ? soic and lfcsp hd2 hd3 f i gur e 2 0 . ha rm onic di stor ti on vs . f r eque nc y fo r v a r i o u s p a c k a g e s 04814-0-037 frequency (mhz) 0.1 1 1 0 100 harmonic dis t ortion (dbc ) ?30 ?50 ?40 ?60 ?80 ?70 ? 100 ?90 ? 110 g = ? 1 v s = 5 v r l = 150 ? v out = 2v p-p hd3 soic and lfcsp hd2 soic hd2 lfcsp f i gur e 2 1 . ha rm onic di stor ti on vs . f r eque nc y fo r v a r i o u s p a c k a g e s 04814-0-033 frequency (mhz) 0.1 1 1 0 100 harmonic dis t ortion (dbc ) ?30 ?40 ?50 ?60 ?70 ?80 ?90 ? 100 ? 110 hd2 soic hd2 lfcsp hd3 soic and lfcsp g = +2 v s = 5 v v out = 2v p-p r l = 150 ? r f = 499 ? f i gur e 2 2 . ha rm onic di stor ti on vs . f r eque nc y fo r v a r i o u s p a c k a g e s 04814-0-034 frequency (mhz) 100 0.1 1 1 0 harmonic dis t ortion (dbc ) ?40 ?50 ?60 ?70 ?80 ?90 ? 100 ? 110 hd2 lfcsp hd2 soic hd3 soic and lfcsp g = +10 v s = 5v v out = 2v p-p r l = 1k ? f i gur e 2 3 . ha rm onic di stor ti on vs . f r eque nc y fo r v a r i o u s p a c k a g e s 04814-0-025 output amplitude (v p-p) 8 012 345 7 6 harmonic dis t ortion (dbc ) ?50 ?70 ?60 ?80 ?90 ? 100 ? 110 ? 120 g = +1 v s = 5 v r l = 1k ? r s = 100 ? f = 10mhz hd3 soic and lfcsp hd2 soic hd2 lfcsp f i gur e 2 4 . ha rm onic di stor ti on vs . output v o l t a g e for v a r i o u s p a c k a g e s
ad8045 rev. a | page 10 of 24 04814-0-024 output amplitude (v p-p) 8 012 345 7 6 harmonic dis t ortion (dbc ) ?40 ?60 ?50 ?70 ?80 ?90 ? 100 ? 110 g = +1 v s = 5 v r l = 150 ? r s = 100 ? f = 10mhz hd3 soic and lfcsp hd2 soic hd2 lfcsp f i gur e 2 5 . ha rm onic di stor ti on vs . output v o l t a g e for v a r i o u s p a c k a g e s 04814-0-026 output voltage (v p-p) 8 012 34567 harmonic dis t ortion (dbc ) ?40 ?50 ?60 ?70 ?80 ?90 ? 100 ? 110 ? 120 hd3 hd2 g = ? 1 v s = 5 v r l = 1k ? f = 10mhz soic and lfcsp f i gur e 2 6 . ha rm onic di stor ti on vs . output v o l t a g e 04814-0-027 output voltage (v p-p) 8 012 34567 harmonic dis t ortion (dbc ) ?40 ?60 ?80 ?50 ?70 ?90 ? 100 ? 110 ? 120 g = ? 1 v s = 5 v r l = 150 ? f = 10mhz hd3 soic and lfcsp hd2 lfcsp hd2 soic f i gur e 2 7 . ha rm onic di stor ti on vs . output v o l t a g e 04814-0-029 frequency (mhz) 100 11 0 harmonic dis t ortion (dbc ) ?30 ?50 ?40 ?60 ?80 ?70 ?90 ? 100 hd3 soic and lfcsp hd2 soic hd2 lfcsp g = +1 v s = 2.5 v out = 2v p-p r l = 1k ? r s = 100 ? f i gur e 2 8 . ha rm onic di stor ti on vs . f r eque nc y fo r v a r i o u s p a c k a g e s 04814-0-031 frequency (mhz) 100 11 0 harmonic dis t ortion (dbc ) ?20 ?30 ?40 ?50 ?60 ?70 ?80 ? 100 ?90 hd2 lfcsp hd2 soic hd3 soic and lfcsp g = +1 v s = 2.5v v out = 2v p-p r l = 100 ? r s = 100 ? f i gur e 2 9 . ha rm onic di stor ti on vs . f r eque nc y fo r v a r i o u s p a c k a g e s 04814-0-035 frequency (mhz) 100 0.1 1 1 0 harmonic dis t ortion (dbc ) ?20 ?30 ?40 ?50 ?60 ?70 ?80 ?90 ? 100 hd2 hd3 g = ? 1 v s = 2.5v v out = 2v p-p r l = 1k ? soic and lfcsp f i gur e 3 0 . ha rm onic di stor ti on vs . f r eque nc y fo r v a r i o u s p a c k a g e s
ad8045 rev. a | page 11 of 24 04814-0-022 output voltage (v p-p) 3.0 0.5 1.0 1.5 2.0 2.5 harmonic dis t ortion (dbc ) ?40 ?50 ?60 ?70 ?80 ?90 ? 100 ? 110 hd3 soic and lfcsp hd2 soic hd2 lfcsp g = +1 v s = +5v r l = 1k ? r s = 100 ? f = 10mhz f i gur e 3 1 . ha rm onic di stor ti on vs . output v o l t a g e for v a r i o u s p a c k a g e s 04814-0-023 output voltage (v p-p) 2.5 0.5 0.7 0.9 1.1 1.3 1.5 1.7 1.9 2.1 2.3 harmonic dis t ortion (dbc ) ?40 ?60 ?50 ?70 ?80 ?90 ? 100 ? 110 g = +1 v s = +5v r l = 150 ? r s = 100 ? f = 10mhz hd3 soic and lfcsp hd2 soic hd2 lfcsp f i gur e 3 2 . ha rm onic di stor ti on vs . output v o l t a g e for v a r i o u s p a c k a g e s 04814-0-076 output voltage step (v) 5 01 234 slew r a t e ( v / s) 1600 1400 1200 1000 800 600 400 200 0 r l = 1k ? v s = 5v positive slew rate negative slew rate f i gure 3 3 . slew ra te vs . o u tput v o l t a g e 04814-0-012 time (ns) 25 0 5 10 15 20 output voltage ( v ) 0.15 0.10 0.05 0 ? 0.05 ? 0.10 ? 0.15 r s = 100 ? r l = 150 ? g = +1 v s = 2.5 or v s = 5v f i g u re 34. sm a ll s i g n al t r ans i ent r e s p ons e f o r v a r i ous s u p p l i es a n d l o ads 04814-0-013 r snub 30 ? c l 10pf r l 1k ? time (ns) 25 0 5 10 15 20 output voltage (v) 0.15 0.10 0.05 0 ? 0.05 ? 0.10 ? 0.15 r l = 1k ? c l = 10pf r snub = 30 ? v s = 5v g = +1 f i g u re 35. sm a ll s i g n al t r ans i ent r e s p ons e f o r v a r i ous s u p p l i es a n d l o ads 04814-0-014 time (ns) 25 0 5 10 15 20 output voltage (v) 0.15 0.10 0.05 0 ? 0.05 ? 0.10 ? 0.15 v s = 2.5v g = +2 r c = 1k ? or r c = 150k ? f i g u re 36. sm a ll s i g n al t r ans i ent r e s p ons e f o r v a r i ous l oads
ad8045 rev. a | page 12 of 24 04814-0-015 time (ns) 25 0 5 10 15 20 output voltage ( v ) 0.20 0.15 0.10 0 0.05 ? 0.05 ? 0.10 ? 0.15 ? 0.20 18pf 0pf g = +2 v s = 5v r l = 1k ? f i g u re 37. sm a ll s i g n al t r ans i ent r e s p ons e wit h capa cit i ve l oad 04814-0-016 time (ns) 25 0 5 10 15 20 output voltage (v) 3 2 1 0 ?1 ?2 ?3 v s = 5v r s = 100 ? g = +2 load = 1k ? or 150 ? f i g u re 38. lar g e s i g n al t r ans i ent r e s p ons e f o r v a r i ous l oads 04814-0-017 time (ns) 25 0 5 10 15 20 output voltage (v) 3 2 1 0 ?1 ?2 ?3 v s = 2.5v v s = 5v r l = 1k ? r s = 100 ? g = +1 f i g u re 39. lar g e s i g n al t r ans i ent r e s p ons e f o r v a r i ous s u p p l i es 04814-0-018 time (ns) 25 0 5 10 15 20 output voltage ( v ) 3 1 2 0 ?1 ?2 ?3 ?4 0pf 10pf 18pf v s = 5v r l = 1k ? g = +2 f i g u re 40. lar g e s i g n al t r ans i ent r e s p ons e wit h capa cit i ve l oad 04814-0-019 time (ns) 25 0 5 10 15 20 output voltage (v) 3 2 1 0 ?1 ?2 ?3 g = ? 1 v s = 5v r l = 1k ? f i g u re 41. lar g e s i g n al t r ans i ent r e s p ons e , inve r t i n g 04814-0-061 time (ns) 200 0 2 0 4 0 6 0 8 0 100 120 140 160 180 inp u t and outp ut v o ltage (v ) 6 4 3 5 2 1 0 ?1 ?2 ?3 ?4 ?5 ?6 g = +1 v s = 5 v f = 5mhz input output f i gure 42. input o v er dr ive r eco ver y
ad8045 rev. a | page 13 of 24 04814-0-062 time (ns) 200 0 2 0 4 0 6 0 8 0 100 120 140 160 180 inp u t and outp ut v o ltage (v ) 6 4 5 2 3 0 1 ?2 ?1 ?4 ?3 ?5 ?6 g = +2 v s = 5 v f = 5mhz 2 input output f i gure 43. o u tput o v er dr ive r e c o ver y 04814-0-053 frequency (hz) 1g 10 100 1k 10k 100k 1m 10m 100m volta g e n o ise ( n v/ h z ) 100 10 1 f i gure 44. v o ltage nois e v s . f r eq uenc y 04814-0-078 frequency (hz) 100m 100 1k 10k 100k 1m 10m curre nt nois e (pa / hz) 100 10 1 f i gure 45. cur r ent nois e v s . f r eq uenc y 04814-0-045 frequency (mhz) 1000 0.01 0.1 1 1 0 100 p o we r s u p p l y re j e ction (db) 0 ?10 ?30 ?20 ?40 ?50 ?60 ?70 ?80 v s = 5 v ? psr +psr f i gure 46. p o wer s u p p ly rej e c t ion vs. f r equ e nc y 04814-0-020 frequency (mhz) 1000 0.1 1 1 0 100 common-mode re j e ction (db) ?30 ?40 ?50 ?60 ?70 ?80 ?90 v s = 5 v r f = 499 ? fi g u r e 4 7 . c o m m o n - m o d e r e j e c t i o n v s . fr e q u e n c y 04814-0-054 frequency (mhz) 1000 1 1 0 100 clos e d -loop inp u t imp e dance ( ? ) 100k 10k 1000 100 10 v s = 5 v g = +1 f i gure 48. input i m pedance v s . f r eque nc y
ad8045 rev. a | page 14 of 24 04814-0-055 frequency (mhz) 1000 1 1 0 100 clos e d -loop outp ut imp e dance ( ? ) 1000 100 10 1 0.1 0.01 g = +1 v s = 5 v f i gure 49. o u tput imped a nce v s . f r eq uenc y 04814-0-040 frequency (mhz) 10 52 0 third-orde r inte rce p t (dbm) 50 48 46 44 42 40 38 34 32 36 30 3 0 4 0 g = +10 v s = 5v r l = 1k ? f i gure 50. thi r d- o r der in terc ept v s . f r e q uenc y 04814-0-021 number of 150 ? loads 10 1 d i ffer e n t ia l ph a se ( d egrees) 0 0.25 0.20 0.15 0.10 0.05 diffe re ntial gain (%) 0 ? 0.02 ? 0.04 ? 0.06 ? 0.08 ? 0.10 ? 0.14 ? 0.18 ? 0.12 ? 0.16 ? 0.20 gain phase g = +2 v s = 5v f i g u re 51. d i f f e r e nt ia l g a in and phas e v s . number of 15 0 ? l o ads 04814-0-063 v offset ( v) 900 ?900 ? 600 ? 300 0 600 300 count 100 80 60 40 20 0 v s = 5v n = 450 x = 50 v = 180 v f i g u re 52. v os d i s t ri bution f o r v s = 5 v 04814-0-077 v offset ( v) 1500 ?300 0 300 600 900 1200 count 80 60 40 20 0 v s = +5v n = 450 x = 540 v = 195 v f i g u re 53. v os d i s t ri bution f o r v s = +5 v 04814-0-058 temperature ( c ) 125 ?40 ? 25 ?10 5 20 50 35 95 110 80 65 offset volta ge ( v) 500 300 100 ? 100 ? 300 ? 500 ? 700 ? 900 ?1100 v s = +5v v s = 5v f i gure 54. o ffset v o ltage v s . t e mper atur e f o r v a r i o u s sup p lies
ad8045 rev. a | page 15 of 24 04814-0-059 temperature (c) 125 ?40 ? 25 ?10 5 20 35 50 65 80 95 110 inp u t bias curre nt ( a) ?1.0 ?1.2 ?1.4 ?1.6 ?1.8 ?2.0 ?2.2 ?2.4 ?2.6 ?2.8 ?3.0 i b +, v s = 5v i b +, v s = 5v i b ?, v s = 5v i b ?, v s = 5v f i gure 55. input b i a s current v s . t e mpe r ature fo r v a r i ous s u p p l i es 04814-0-057 temperature (c) 125 ?40 ? 25 ?10 5 20 35 50 65 80 95 110 output saturation voltage (v) 1.20 1.15 1.10 1.05 1.00 0.95 0.90 r l = 1k ? v s = 5v v s = 5v ?v s + v out +v s ? v out ?v s + v out +v s ? v out f i g u re 56. o u t p ut s a t u r a t i on v o lt ag e v s . t e mper at ure f o r v a ri ous su p p l i es 04814-0-056 temperature ( c ) 125 ?40 ? 25 ?10 5 20 35 50 65 80 110 95 s u p p l y curre nt (ma) 17.0 16.5 16.0 15.5 15.0 14.5 v s = 5v v s = 5v f i gure 57. sup p l y current v s . t e mper at ur e f o r v a r i o u s sup p lies 04814-0-044 load (k ? ) 10 0.1 1 outp ut s a turation v o ltage (v ) 1.5 1.0 0.5 0 ?0.5 ?1.0 ?1.5 v s = 5v v s = +5v +v s ? v out ?v s ? v out f i g u re 58. o u t p ut s a t u r a t i on v o lt ag e v s . l oad f o r v a ri ous sup p l i es 04814-0-047 v out (v) 4 ? 4 ? 3 ? 2 ? 1 0123 v os (mv ) 4 3 1 2 0 ?1 ?2 ?3 ?4 r l = 1k ? r l = 150 ? f i g u re 59. input o f f s et v o lt ag e v s . o u t p ut v o lt ag e f o r v a ri ous l oads 04814-0-046 time (ns) 22.5 0 2.5 5.0 7.5 10.0 12.5 15.0 17.5 20.0 settling (%) 0.30 0.20 0.10 0 ? 0.10 ? 0.20 ? 0.30 g = +2 v s = 5 v v out = 2v p-p r l = 150 ? r f = 499 ? f i g u re 60. sho r t t e r m 0.1% s e t t l ing ti me
ad8045 rev. a | page 16 of 24 circuit configura t ions wid e b a nd o p er a t ion f i g u re 6 1 an d fi g u re 6 2 show t h e re c o m m e n d e d c i rc u i t co nf igura t io n s fo r n o ni n v er t i n g a n d i n v e r t in g am plif iers. i n uni t y ga in (g = +1) a p p l ic a t io n s , r s he l p s t o r e d u ce hig h f r e q u e nc y p e a k i n g . i t i s not ne e d e d for a n y ot h e r c o n f i g u r a t i o ns . f o r more i n f o r m a t i o n on l a y o ut , s e e t h e pr i n t e d c i rc u i t b o ard l a y o u t secti o n . t h e re s i stor a t t h e output of t h e am pl i f i e r , l a b e l e d r snu b , i s u s e d o n l y when dr i v in g la rg e c a p a ci t i v e lo ads. u s in g r snu b i m prove s st abi l it y an d m i n i m i z e s r i ng i n g a t t h e output . f o r more i n f o r - ma t i on, s e e t h e dr i v in g c a p a ci t i v e l o ads s e c t ion. 04814-0-074 ad8045 r g r f r s r snub v in v out +v s + 10 f 0.1 f ?v s + 10 f 0.1 f f i g u re 61. no ni nve r ting c o nf igur ation 04814-0-075 ad8045 r g r f r = r g ||r f v in +v s + 10 f 0.1 f ?v s + 10 f 0.1 f r snub v out f i g u re 62. inve r t ing conf ig u r at ion
ad8045 rev. a | page 17 of 24 theor y of opera tion the ad8045 is a hig h s p e e d v o l t a g e f e e d back am p l if ier fa b r i- ca ted on adi s s e co nd g e n e ra tion ex tra f a s t c o m p lem e n t a r y b i p o la r (xfcb) p r o c es s. an h-b r idg e in p u t s t ag e is us ed t o a t ta in a 1400 v/s s l ew r a t e and lo w dis t o r tio n in addi tion t o a l o w 3 nv / hz i n put volt age noi s e. supply c u r r en t and of f s e t volt age are l a s e r t r i m me d for opt i m u m p e r f or m a nc e. frequenc y response the ad8045 s op en-lo o p r e sp on s e o v er f r eq uen c y can b e a ppro x i m a t e d by t h e i n te g r a t or re sp ons e s h o w n i n f i g u re 6 3 . f crossover = 400mhz frequency (mhz) v out /v in (db) 0 1 1 0 100 f 1000 v out /v in = f crossover v in v out 04814-0-008 f i gure 63. o p en-l oop resp onse the clos e d -lo o p t r a n sfer f u n c t i o n fo r t h e n o ni n v er t i n g co nf igu- ra t i o n is sh own in f i gur e 64 and is wr i t ten a s () g crossover g f f g crossover in out r f r r r r f v v + + + = 2 s ) ( 2 wher e: s is (2 j ) f . f cr osso ver is t h e f r e q uen c y w h er e t h e am plif ier s o p en-lo o p gain eq uals 1 (0 d b ). d c ga in is t h erefo r e () g f g in out r r r v v + = c l o s e d -lo o p ?3 db b a nd w i d t h e q ua ls () f g g crossover in out r r r f v v + = t h e cl o s e d - l o o p b a n d w i d t h i s i n ve r s ely prop or t i on a l to t h e n o is e gain o f t h e o p a m p cir c ui t , (r f + r g )/r g . t h i s s i m p l e m o d e l c a n b e us e d to p r e d ic t t h e ?3 db b a nd w i d t h fo r n o i s e g a i n s a b o v e +2. t h e a c t u al ba n d w id th o f ci r c u i ts wi th n o i s e ga in s a t o r b e lo w +2 is hig h er d u e t o t h e i n f l uen c e o f o t h e r p o les p r es en t i n t h e r e al o p am p . 04814-0-009 r g r f v in v out r s +? f i g u re 64. no ni nve r ting c o nf igur ation dc errors f i g u r e 65 s h o w s th e d c e r r o r co n t ri b u ti o n s . th e t o tal o u t p u t er r o r v o l t a g e is ? ? ? ? ? ? + + + ? ? ? ? ? ? + ? = ? + g f g os f b g f g s b (error) out r r r v r i r r r r i v 04814-0-010 r g r f v os v out r s +? i b + i b ? f i gure 65. a m pl ifi e r dc e r r o rs the v o l t a g e er r o r d u e t o i b + a nd i b ? is mini mi ze d if r s = r f ||r g . t o i n cl ude t h e e f fe c t s o f co mm on- m o d e an d p o w e r s u p p ly re j e c t i o n , mo d e l v os as cmr v psr v v v cm s os os nom ? + ? + = wher e: nom os v is t h e o f fs et v o lt a g e a t n o mi nal co ndi t i on s. v s is t h e cha n g e in t h e p o w e r s u p p ly v o l t a g e f r o m n o minal co ndi t i on s. ps r i s th e po w e r s u p p l y r e jecti o n . c mr is t h e co mm on- m o d e r e je c t io n. v cm is t h e chan g e in comm o n -mo d e v o l t a g e f r o m n o minal co ndi t i on s.
ad8045 rev. a | page 18 of 24 outpu t n o ise f i gur e 66 s h o w s t h e con t r i b u t o rs t o t h e n o is e a t t h e o u t p u t o f a non i n v e r t i ng c o n f i g u r a t i o n . r g r f v out r s +? v en v rf v rg v rs i en + i en ? 04814-0-011 f i gure 66. a m pl ifi e r dc e r r o rs ven , in+ , a n d in? a r e d u e to t h e am plif ier . , , a n d a r e d u e t o t h e fe e d b a ck n e tw o r k r e sis t o r s. r f r v g r v s r v g a nd r f , and so u r c e r e s i s t o r , r s . t o t a l o u t p u t v o l t a g e n o i s e , en out v _ , i s t h e rm s s u m o f all th e c o n t ri b u ti o n s . = en out v _ () () () () ( ) 2 2 2 2 2 4 4 4 n s n g f n g f n s n g ktr g ktr ktr g ||r r in g r in ven g + + + ? + + + wher e: g n is t h e n o is e g a in ? ? ? ? ? ? + g g f r r r . ven is t h e o p am p i n p u t v o l t a g e n o i s e . i n is t h e o p am p i n p u t c u r r en t n o is e . t a b l e 7 lis t s t h e exp e c t e d ou t p u t v o l t a g e n o is e sp e c t r al den s i t y fo r s e v e ra l ga in co nf igura t io n s . ta ble 7. noi s e a nd ba ndwi d t h for va ri ous ga i n s g a i n r f r g r s ?3 db band wid t h 1 ou tpu t noise (nv/hz) + 1 0 ? 1 0 0 1 g h z 3 . 3 + 2 4 9 9 4 9 9 0 4 0 0 m h z 7 . 4 + 5 4 9 9 1 2 4 0 9 0 m h z 1 6 . 4 + 1 0 4 9 9 5 6 0 40 m h z 3 1 ? 1 4 9 9 4 9 9 n / a 3 0 0 m h z 7 . 4 1 r l = 1 k?.
ad8045 rev. a | page 19 of 24 appli c a t ions lo w d i s t o r t i o n p i n o u t the ad8045 lf cs p p a c k a g e f e a t ur es analog d e vices n e w lo w disto r t i o n pi n o u t . t h e ne w p i no u t p r o v ides t w o ad va n t a g es o v e r th e tra d i t i o n a l p i n o u t . f i r s t, i m p r o v ed seco n d h a rm o n i c d i stor t i on p e r f or m a nc e, w h i c h i s a c c o m p l i s h e d by t h e p h y s i c a l s e p a ra t i on o f t h e n o ni n v er t i n g i n p u t pin and t h e nega t i v e p o w e r s u p p ly p i n. s e cond , t h e si m p lif i c a t i o n o f t h e l a yo u t d u e t o t h e de di ca te d fe e d b a ck p i n and e a s y r o u t in g o f t h e ga in s et r e sisto r b a ck t o t h e i n v e r t in g in p u t p i n. this a l lo ws a com p ac t l a yo u t , w h ich hel p s to mini mi ze p a rasi t i cs an d i n cr e a s e st ab i l i t y . t h e tra d i t i o n a l so i c p i n o u t has been s l i g h t l y m o d i f i ed a s w e l l to in co r p o r a t e a de dic a te d fe e d b a ck p i n. pi n 1, p r e v io usly a n o co nn e c t p i n o n th e a m plif i e r , is n o w a de dica te d f e e d b a ck p i n. th e n e w p i n o u t r e d u ces p a ra si t i c s a n d sim p li f i es t h e bo a r d la y o u t . exi s ti n g a p p l ica t i o n s th a t u s e th e tra d i t i o n a l so i c p i n o u t ca n t a k e f u l l ad van t a g e o f t h e ou ts t a ndin g p e r f o r m a n c e o f fer e d b y th e ad8045. an e l ec tr ical in s u la t o r ma y b e r e q u ir ed if the so i c re st s on t h e g r ou nd p l a n e or ot he r me t a l t r a c e. t h i s i s c o ve re d in m o r e det a i l i n t h e e x p o s e d p a dd le s e c t ion o f t h is d a t a sh e et. i n exis ting desig n s, whic h ha v e p i n 1 tie d t o g r o u n d o r t o a n o t h e r p o t e n t ial , sim p l y lif t p i n 1 o f th e ad80 45 o r r e m o v e the p o t e n t ial on t h e p i n 1 s o lder p a d . th e desig n er do es n o t n e e d to us e t h e de di ca t e d fe e d b a ck p i n to p r o v ide fe e d b a ck fo r t h e ad8045. th e ou t p u t p i n o f th e ad8045 can s t il l be us e d t o p r o - vide f e e d b a c k to th e in v e r t in g in p u t o f t h e ad8045. high spee d adc drive r w h en us e d as an ad c dr i v er , th e ad8045 o f f e rs r e s u l t s co m p a- r a bl e to t r ans f or me r s i n d i s t or t i on p e r f or m a nc e . m a n y a d c a p plic a t ion s r e quir e t h a t t h e a n a l og in p u t sig n a l b e dc -co u ple d a nd o p er a t e o v e r a wide f r e q uen c y ra n g e . u n der t h es e r e q u ir e - m e n t s, o p er a t ional a m plif iers ar e v e r y ef fe c t i v e in t e r f aces t o ad cs. a n o p am p in t e r f ace p r o v ides t h e a b i l i t y t o a m plif y a nd le v e l shif t t h e i n p u t sig n al t o b e co m p a t i b le wi t h t h e i n p u t ra n g e of t h e a d c . u n l i ke t r an s f or me r s , op e r a t i o n a l a m pl i f i e r s c a n b e o p er a t e d o v er a w i d e f r e q u e n c y r a nge dow n to and i n cl u d ing dc . f i gur e 67 s h o w s th e ad8045 as a dc-co u p l e d dif f er en tial dr i v er fo r t h e ad9244 , a 14-b i t 65 ms ps ad c. th e tw o a m p l if iers a r e co nf igur e d in no ni n v er t i n g and in v e r t in g mo de s. b o t h a m plif i- ers a r e s et wi t h a n o i s e ga i n o f +2 t o p r o v ide b e t t er b a ndwi d t h ma t c h i ng. th e i n v e r t in g am plif i e r is s et fo r a ga in o f C1, w h i l e t h e n o ni n v er t i ng is s et fo r a ga i n o f +2. th e n o ni n v er t i n g i n p u t is divide d b y 2 i n o r der to n o r m a l iz e i t s ou t p u t a nd ma k e i t eq ual t o t h e in v e r t i n g o u t p u t . this dc-co u p l e d dif f er en t i al dr i v er is best s u i t e d f o r 5 v op e r a t i o n i n w h i c h opt i m u m d i stor t i on p e r f or m a n c e i s re qu i r e d a nd t h e i n p u t si g n al is g r o u n d refer e n c e d . v in a v in b cm l a d 9244 511 ? 511 ? 511 ? 511 ? 511 ? 511 ? v in v cml ? v in ad8045 ad8045 0.1 f 20pf 1 f 0.1 f op27 511 ? 511 ? v cml + v in 33 ? 33 ? 2.5k ? 100 ? 04814-0-066 f i gure 6 7 . hi gh speed adc dri v er the o u t p u t s o f t h e ad8045s a r e cen t er e d abo u t th e ad9244 s co mm o n - m o d e ra n g e o f 2.5 v . the co mm on- m o d e r e fer e n c e v o l t a g e f r o m t h e ad9244 is b u f f er ed a nd f i l t er e d via the op 2 7 a nd fe d to t h e no ni n v er t i n g r e sisto r n e tw o r k us e d i n t h e le vel shif t i ng c i rc u i t . the s p ur io us-f r e e d y namic ra ng e (s fd r) p e r f o r ma n c e is s h own in f i gur e 68. f i gur e 69 s h o w s a 50 mh z s i n g le-t one fft pe rf o r m a n c e . 04814-0-067 input frequency (mhz) 100 11 0 s f dr (dbc ) 120 100 80 60 40 20 0 ad8045 fi g u r e 6 8 . s f d r v s . fr e q u e n c y
ad8045 rev. a | page 20 of 24 04814-0-068 frequency (mhz) 0 5 10 15 20 25 30 distortion ( d bc) 0 ?20 ?40 ?60 ?80 ? 100 ? 120 a in = ? 1dbfs snr = 69.9dbc sfdr = 65.3dbc f i g u re 69. sing l e - t one ff t , f in = 50 m h z, s a mpl e rate = 65 m s ps sho w n i n the f i rst ny qui s t z o ne 90 mhz a c tive l o w - p a ss fil t er (l pf) a c ti v e f i l t er s a r e us ed in man y a p p l ic a t io n s s u ch as an t i aliasin g f i l t ers a nd hig h f r eq uen c y co mm unic a t ion if st r i ps. w i t h a 400 m h z ga in b a n d wid t h p r o d uc t and hig h s l ew ra t e , th e ad8045 is an ideal can d ida te f o r ac ti v e f i l t ers. f i gur e 70 show s t h e f r e q u e nc y re sp ons e o f t h e 9 0 m h z l p f . i n a d d i t i on t o t h e b a ndwi d t h re q u ir e m en ts, t h e s l e w r a t e m u s t b e c a p a b l e o f s u p p o r t i n g t h e f u l l p o w e r b a n d wi d t h o f t h e f i l ter . i n t h is cas e , a 90 mh z b a n d wi d t h w i t h a 2 v p-p o u t p u t s w i n g r e q u ir es a t le ast 1200 v/s. this p e r f o r ma n c e is ac hievab le o n l y a t 90 m h z be ca us e o f t h e ad8045 s wide ba ndwid th and hig h s l ew r a t e . the cir c ui t sh own in f i gur e 73 is a 90 mh z, 4-p o le , sal l en-k ey , lp f . th e f i l ter co m p r i s e s tw o iden t i c a l cas c ade d sal l en- k e y lp f s e c t io n s , e a ch wi t h a f i xe d ga in o f g = +2. th e n et gain o f t h e f i l t er is eq ual t o g = +4 o r 12 db . th e ac t u al ga in sh o w n in f i gur e 70 is o n l y 6 db . this is d u e t o th e o u t p u t v o l t a g e bein g divide d i n ha lf b y t h e s e r i es ma tchin g ter m ina t io n r e sisto r , r t , a nd t h e lo ad r e sisto r . s e t t in g t h e r e sist o r s a nd c a p a ci to rs e q ual t o e a ch o t h e r g r e a t l y sim p lif i es t h e desig n e q u a t i on s fo r t h e sal l en-k e y f i l t er . the co r n er f r eq uen c y , o r ?3 db f r eq uen c y , can b e des c r i be d b y the eq ua ti o n rc f c 2 1 = t h e qu a l it y f a c t or , or q, is sh o w n in t h e e q u a t i on k q ? = 3 1 the ga i n , o r k, o f t h e cir c ui ts ar e 1 1, + = + = r7 r8 k stage second r4 r3 k stage first resis t o r val u es a r e k e pt lo w fo r minimal n o i s e c o n t r i b u t i o n , of f s e t vo lt age, a n d opt i m a l f r e q u e nc y re sp ons e . d u e to t h e l o w ca p a ci t a n c e val u es us e d in t h e f i l t er cir c ui t, t h e pc b la y o u t a n d minimiza t i o n o f p a r a si t i cs is cr i t ica l . a fe w p i co f a rads ca n det u n e th e f i l t e r s co rn er f r eq ue n c y , f c . t h e ca pa c i t o r v a l u e s s h o w n in f i gur e 73 ac t u al ly in co r p o r a te s o m e s t ra y pcb ca p a c i t a n c e. c a p a ci t o r s e le c t io n is cr i t ica l for o p t i ma l f i l t er p e r f o r ma n c e . c a p a ci t o rs wi t h lo w t e m p era t ure co ef f i cien ts, such as np o cera mic c a p a ci to rs a n d sil v er mica , a r e g o o d cho i ces f o r f i l t er e l emen t s . 04814-0-006 frequency (mhz) 0.1 1 1 0 100 1000 gain ( d b) ?40 ?30 ?20 0 ?10 10 ?50 ?60 ?70 ?80 ?90 20 f i gur e 7 0 . 90 m h z l o w - p a ss f i l t er r e sp o n se
ad8045 rev. a | page 21 of 24 04814-0-069 ch1 m4.00ns a ch1 0.00v 1 50.0mv f i g u re 71. sm a ll s i g n al t r ans i ent r e s p ons e of 9 0 m h z l p f 04814-0-070 ch1 m4.00ns a ch1 0.00v 1 500mv f i g u re 72. lar g e s i g n al t r ans i ent r e s p ons e of 9 0 m h z l p f u1 c1 7.1pf c2 7.1pf r1 249 ? r t 49.9 ? r2 249 ? r3 499 ? r5 249 ? r4 499 ? c5 5pf r9 24.9 ? r t 49.9 ? input ?5v +5v 0.1 f 0.1 f 10 f 10 f u1 c3 7.1pf c4 7.1pf r6 249 ? r8 499 ? r7 499 ? ?5v +5v 0.1 f 0.1 f 10 f 10 f output 04814-0-005 f i g u re 73. 4- p o l e , 9 0 m h z, s a lle n-key l o w- p a s s f ilt er
ad8045 rev. a | page 22 of 24 printed circuit board layout laying out the printed circuit board (pcb) is usually the last step in the design process and often proves to be one of the most critical. a brilliant design can be rendered useless because of a poor or sloppy layout. since the ad8045 can operate into the rf frequency spectrum, high frequency board layout con- siderations must be taken into account. the pcb layout, signal routing, power supply bypassing, and grounding all must be addressed to ensure optimal performance. signal routing the ad8045 lfcsp features the new low distortion pinout with a dedicated feedback pin and allows a compact layout. the dedicated feedback pin reduces the distance from the output to the inverting input, which greatly simplifies the routing of the feedback network. when laying out the ad8045 as a unity gain amplifier, it is rec- ommended that a short, but wide, trace between the dedicated feedback pin and the inverting input to the amplifier be used to minimize stray parasitic inductance. to minimize parasitic inductances, ground planes should be used under high frequency signal traces. however, the ground plane should be removed from under the input and output pins to minimize the formation of parasitic capacitors, which degrades phase margin. signals that are susceptible to noise pickup should be run on the internal layers of the pcb, which can provide maximum shielding. power supply bypassing power supply bypassing is a critical aspect of the pcb design process. for best performance, the ad8045 power supply pins need to be properly bypassed. a parallel connection of capacitors from each of the power supply pins to ground works best. paralleling different values and sizes of capacitors helps to ensure that the power supply pins see a low ac impedance across a wide band of frequencies. this is important for minimizing the coupling of noise into the amplifier. starting directly at the power supply pins, the smallest value and sized component should be placed on the same side of the board as the amplifier, and as close as possible to the amplifier, and connected to the ground plane. this process should be repeated for the next larger value capacitor. it is recommended for the ad8045 that a 0.1 f ceramic 0508 case be used. the 0508 offers low series inductance and excellent high frequency performance. the 0.1 f case provides low impedance at high frequencies. a 10 f electrolytic capacitor should be placed in parallel with the 0.1 f. the 10 f capacitor provides low ac impedance at low frequencies. smaller values of electrolytic capacitors may be used depending on the circuit requirements. additional smaller value capacitors help to provide a low impedance path for unwanted noise out to higher frequencies but are not always necessary. placement of the capacitor returns (grounds), where the capaci- tors enter into the ground plane, is also important. returning the capacitors grounds close to the amplifier load is critical for distortion performance. keeping the capacitors distance short, but equal from the load, is optimal for performance. in some cases, bypassing between the two supplies can help to improve psrr and to maintain distortion performance in crowded or difficult layouts. it is brought to the designers attention here as another option to improve performance. minimizing the trace length and widening the trace from the capacitors to the amplifier reduce the trace inductance. a series inductance with the parallel capacitance can form a tank circuit, which can introduce high frequency ringing at the output. this additional inductance can also contribute to increased distor- tion due to high frequency compression at the output. the use of vias should be minimized in the direct path to the amplifier power supply pins since vias can introduce parasitic inductance, which can lead to instability. when required, use multiple large diameter vias because this lowers the equivalent parasitic inductance. grounding the use of ground and power planes is encouraged as a method of proving low impedance returns for power supply and signal currents. ground and power planes can also help to reduce stray trace inductance and to provide a low thermal path for the amplifier. ground and power planes should not be used under any of the pins of the ad8045. the mounting pads and the ground or power planes can form a parasitic capacitance at the amplifiers input. stray capacitance on the inverting input and the feedback resistor form a pole, which degrades the phase margin, leading to instability. excessive stray capacitance on the output also forms a pole, which degrades phase margin.
ad8045 rev. a | page 23 of 24 expose d p a ddle the ad8045 f e a t ur es an exp o s e d p a ddle , which lo w e rs th e th er mal r e sis t ance b y 25% co m p a r ed t o a standar d so i c p l as tic p a c k a g e . the exp o s e d p a ddle o f th e ad8045 is in t e r n al l y co n- n e ct ed t o th e n e g a ti v e po w e r s u p p l y p i n . th e r e f o r e , wh en la yin g o u t t h e b o a r d , t h e exp o s e d p a ddle m u s t e i t h er b e co nne c t e d t o th e n e ga ti v e po w e r s u p p l y o r le ft f l oa ti n g (e lect ri call y i s o l a t e d ). s o ld e r i n g th e e x posed pa d d le t o th e n e g a ti v e po w e r s u p p l y m e tal en s u r e s m a xim u m t h er mal tra n sf er . f i gur e 74 a n d f i gur e 75 s h o w t h e p r o p er la you t fo r co nn e c t i ng t h e so ic an d lfcs p exp o s e d pa d d le t o th e n e g a ti v e s u p p l y . 04814-0-071 f i gure 74. soic exposed p a dd le lay o u t the us e o f t h er mal v i as o r h e a t p i p e s can als o b e i n co r p o r a t e d in t o t h e desig n o f t h e m o un t i ng p a d fo r t h e ex p o s e d p a ddle . t h ese a d d i ti o n al vi a s h e l p t o lo w e r th e o v e r all th e t a j u n c ti o n t o amb i e n t ( ja ). u s in g a h e a v i e r w e ig h t cop p er o n t h e s u r f ace t o w h ich t h e a m pl i f ier s exp o s e d p a dd le is s o lder e d can g r e a t l y r e d u ce t h e o v eral l th er mal r e sis t a n ce s e e n b y t h e ad8045. 04814-0-073 f i gure 75. lf cs p exp o sed p a dd le lay o ut f o r exis tin g desig n s tha t wan t to in co r p o r a t e t h e ad8045, e l e c t r ica l ly is ola t in g t h e exp o s e d p a dd le is an o t h e r o p t i on. i f t h e exp o s e d p a dd le is e l e c t r ica l ly is ola t e d , t h e t h er ma l dissi p a t ion is p r i m a r il y th r o u g h th e lea d s , a n d th e th e r m a l r e s i s t a n ce o f th e p a c k a g e n o w a p p r o a c h es 125c/w , t h e standa rd so i c ja . h o w e v e r , a th e r m a ll y co n d ucti v e a n d e l ectri c all y i s o l a t e d pa d ma ter i a l ma y b e us e d . a t h er ma l l y co n d uc t i ve sp acer , such as t h e b e rg q u ist c o m p an y s si l-p a d , is a n exce l l en t s o l u t i o n t o t h is p r ob lem. f i gur e 76 s h o w s a typ i cal i m plemen t a t i o n usin g th e r m a l pa d ma t e ri al . 04814-0-072 thermal conductive insulator f i g u r e 7 6 . s o i c wi th t h er m a l c o n d u c ti v e p a d ma t e ri a l the t h er mal p a d p r o v ides hi g h t h er mal con d uc t i v i ty b u t is ola t es t h e exp o s e d p a ddle f r o m g r o u nd o r o t h e r p o ten t i al. i t is r e co mme n d e d , w h en p o s s i b le , to s o lder t h e p a ddle t o t h e nega - ti v e po w e r s u p p l y p l a n e o r tra c e f o r m a xi m u m t h e r m a l tra n s f e r . n o t e t h a t s o lder in g t h e p a ddle to g r o u n d sh o r ts t h e n e g a t i ve po w e r s u p p l y t o gr o u n d a n d c a n ca u s e i r r e pa ra b l e da m a g e t o th e ad8045. drivi n g c a p a c i ti ve l o ads i n ge n e ra l, hig h sp e e d am plif iers ha v e a dif f i c u l t t i m e dr ivin g ca p a c i t i v e lo ads. this is p a r t ic u l a r ly t r ue in lo w clos e d -lo o p ga in s, w h er e t h e phas e ma rg in i s t h e lo w e s t . the dif f i c u l t y a r is es b e ca us e t h e lo ad c a p a ci t a n c e , c l , f o rm s a po l e w i th th e o u t p u t re s i st anc e , r o , o f t h e am plif ier . the p o le can b e des c r i b e d b y t h e eq ua ti o n l o p c r f 2 1 = i f th is po le o c cur s t o o c l ose t o th e uni t y ga in cr os so v e r po in t, t h e phas e ma rg i n deg r ades. thi s is d u e t o t h e addi t i onal phas e l o s s a s s o c i a t e d w i th th e po l e . the ad8045 o u t p u t can dr i v e 1 8 pf o f l o ad ca p a ci tan c e dir e c t l y , in a gain o f +2 wi t h 30 % o v er s h o o t, as sh o w n in f i gur e 37. l a rg er ca p a c i t a n c e v a l u es can b e dr i v en b u t m u s t us e a sn ub- bi ng re s i stor ( r sn ub ) a t t h e output of t h e a m pl i f i e r , a s show n i n f i gur e 61 a nd f i gur e 62. a ddi ng a sma l l s e r i es r e sisto r , r snu b , cr ea t e s a z e r o th a t ca n c e l s t h e p o le i n tr od uce d b y th e loa d c a pa ci ta n c e . t y p i c a l v a l u e s f o r r snu b ca n ran g e f r o m 25 ? t o 50 ?. th e va l u e is typ i cal l y a r r i v e d a t em p i r i cal l y a n d b a s e d o n t h e cir c ui t r e q u i r em e n ts.
ad8045 rev. a | page 24 of 24 outline dimensions 0.25 (0.0098) 0.17 (0.0068) 0.25 (0.0098) 0.10 (0.0039) 1.27 (0.050) 0.40 (0.016) 0.50 (0.020) 0.25 (0.010) 1.75 (0.069) 1.35 (0.053) seating plane 4 1 5. 0 0 ( 0 . 1 97 ) 4.90 (0.193) 4. 8 0 ( 0 . 1 89 ) 4.00 (0.157) 3.90 (0.154) 3.80 (0.150) 1.27 (0.05) bsc 6.20 (0.244) 6.00 (0.236) 5.80 (0.228) 0.51 (0.020) 0.31 (0.012) coplanarit y 0.10 top view 2. 29 ( 0 . 0 9 2 ) bottom view (pins up) 2. 29 ( 0 . 0 9 2 ) controlling dimensions are in millimeters; inch dimensions (in parentheses) are rounded-off millimeter equivalents for reference only and are not appropriate for use in design compliant to jedec standards ms-012 45 8 0 85 f i g u re 77. 8-l e ad s t anda r d s m a l l o u t l ine p a ckag e w i t h e x pos e d p a d [s oic_ n_e p ], na rro w bod y (r d - 8-1)d im en s i ons s h o wn in m i l l i m e te rs and ( i n c he s ) 1 ex po s e d pa d (b o t t o m v ie w) 0.50 bsc 0.60 max pin 1 indicator 1.50 ref 0.50 0.40 0.30 0.25 min 0.45 2.75 bsc sq top view 12 max 0.80 max 0. 65 t y p seating plane pin 1 indicato r 0.90 0.85 0.80 0.30 0.23 0.18 0.05 max 0.02 nom 0.20 ref 1.90 1.75 1.60 4 1.60 1.45 1.30 3.00 bsc sq 5 8 f i g u re 78. 8-l e ad l e ad f r a m e ch ip s c al e p a ck ag e [lfcs p ], 3 m m 3 m m b o dy (cp - 8- 2)d im e n s i ons s h o w n in m i ll im ete r s ordering guide model minimum ordering quantity temperature r a nge package descri ption package o p t i o n b r a n d i n g ad8045ard 1 C40c to +125c 8-lead soic_n_ ep rd-8-1 ad8045ard-re el 2,500 C40c to +125c 8-lead soic_n_ ep rd-8-1 ad8045ard-re el7 1,000 C40c to +125c 8-lead soic_n_ ep rd-8-1 ad8045ardz 1 1 C40c to +125c 8-lead soic_n_ ep rd-8-1 ad8045ardz-reel 1 2,500 C40c to +125c 8-lead soic_n_ ep rd-8-1 ad8045ardz-r eel7 1 1,000 C40c to +125c 8-lead soic_n_ ep rd-8-1 AD8045ACP-R2 250 C40c to +125c 8-lead lfcsp cp-8-2 h8b ad8045acp-re el 5,000 C40c to +125c 8-lead lfcsp cp-8-2 h8b ad8045acp-re el7 1,500 C40c to +125c 8-lead lfcsp cp-8-2 h8b ad8045acpz-r2 1 250 C40c to +125c 8-lead lfcsp cp-8-2 h8b ad8045acpz-reel 1 5,000 C40c to +125c 8-lead lfcsp cp-8-2 h8b ad8045acpz-r eel7 1 1,500 C40c to +125c 8-lead lfcsp cp-8-2 h8b 1 z = pb-free part. ? 2004 analo g de vices, inc. all rights reserve d . tra d em arks and registered tra d ema r ks are the prop erty of their respective owners . d04814C0C 9/04(a)

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