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700 mhz to 2700 mhz quadrature modulator ad8349 rev. 0 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 . specifications subjec t to chan 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 . features output freq ue ncy range: 700 mhz to 27 00 m hz modulation bandwidth: dc to 160 mh z (large signal bw) 1 db output co mpression: 5.6 dbm @ 2 140 m hz output disable function: output below C50 d b m in < 50 ns noise floor: C156 dbm/hz phase q u adrat u re error: 0.3 d e grees @ 2140 mhz amplitude balance: 0.1 db single supply: 4.75 v to 5.25 v pin compatible with ad 8345/ ad83 46 16-lea d expose d-padd le tsso p package applic ati o ns cellular/pcs communication systems infra s tr ucture wcdma/cdm a 2000/pcs/gsm / edge wireless la n/ wireless local l oop lmds/broadba nd wireless access syst ems func tio n a l block di agram ibbp ibbn c om1 c om1 loin qbbp qbbn com3 com3 vps2 loip vps1 enop vout com3 com2 03570-0-001 16 15 14 13 12 11 10 9 1 2 3 4 5 6 7 8 a d 8349 phase splitter bias fi g u r e 1 produc t d e scripti o n the ad8349 is a silico n, m o n o l i thic, rf q u adra t u r e m o d u la t o r tha t is desig n e d f o r us e f r o m 70 0 mh z t o 2700 mh z. i t s exce l l en t phas e acc u rac y a n d am pli t ude b a lan c e ena b le hig h p e r f or m a nc e d i re c t r f mo d u l a t i on f o r c o m m u n i c at i o n s y ste m s . the dif f er en t i al l o in p u t sig n al is b u f f er e d , a nd t h e n s p li t in t o a n in-p hase (i) signal a nd a q u ad ra t u r e -p has e (q) signal usin g a p o l y phas e phas e s p li t t er . th es e tw o l o sig n als a r e f u r t h e r b u f f er e d an d t h en mixe d w i t h t h e co r r esp o n d i n g i cha n n e l and q cha nnel b a s e b a nd sig n a l s i n tw o gi lb er t cel l mixers. th e mixers o u t p uts a r e t h e n s u mm e d t o g e t h er in t h e o u t p ut a m plif ier . t h e ou t p ut a m pl if ier is desig n e d t o d r i v e 50 ? lo ads. t h e r f output c a n b e s w itc h e d on a n d of f w i t h i n 5 0 ns by a p p l yin g a con t rol p u ls e t o th e e n o p p i n. the ad8349 can b e us ed as a dir e c t -t o-rf m o d u l a t o r in dig i ta l co mm unic a t io n sys t em s s u ch as gs m, cd ma, a nd w c d m a b a s e st a t ion s , and qps k o r q a m b r o a d b and w i r e less access t r a n smi t ters. i t s hig h d y na mic r a n g e and hig h m o d u l a t i on acc u rac y als o m a k e i t a p e r f e c t if m o d u la t o r in lo cal m u l t i p o i n t dist r i bu t i on s y ste m s ( l m d s ) u s ing c o m p l e x mo d u l a t i on fo r m a t s. the ad8349 is fa b r ica t e d usin g analog de vices ad van c e d co m p le m e n t a r y silico n b i p o l a r p r o c es s, a nd is a v a i lab l e in a 16- l e a d e x posed- pa d d l e ts s o p p a c k a g e . i t s pe rf o r m a n c e i s s p ecif ie d o v er a C40c t o +85c t e m p era t ur e ra n g e .
ad8349 rev. 0 | page 2 of 28 table of contents specifications..................................................................................... 3 absolute maximum ratings............................................................ 5 pin configuration and functional descriptions.......................... 6 equivalent circuits ........................................................................... 7 typical performance characteristics ............................................. 8 circuit description......................................................................... 14 overview...................................................................................... 14 lo interface................................................................................. 14 v-to-i converter......................................................................... 14 mixers .......................................................................................... 14 d-to-s amplifier......................................................................... 14 bias circuit .................................................................................. 14 output enable ............................................................................. 14 basic connections .......................................................................... 15 baseband i and q inputs ........................................................... 15 single-ended baseband drive .................................................. 15 lo input drive level ................................................................. 16 frequency range ........................................................................ 16 lo input impedance matching ................................................ 16 single-ended lo drive.............................................................. 17 rf output.................................................................................... 17 output enable ............................................................................. 17 baseband dac interface ........................................................... 18 ad9777 interface ....................................................................... 18 biasing and filtering .................................................................. 18 reducing undesired sideband leakage .................................. 18 reduction of lo feedthrough ................................................. 19 sideband suppression and lo feedthrough versus temperature ................................................................................ 19 single sideband performance versus baseband drive level 20 improving third harmonic distortion................................... 20 applications..................................................................................... 21 3gpp wcdma single-carrier application........................... 21 wcdma multicarrier application ........................................ 21 gsm/edge application ........................................................... 22 soldering information ............................................................... 23 lo generation using plls ....................................................... 23 transmit dac options ............................................................. 23 evaluation board ............................................................................ 24 characterization setups................................................................. 26 ssb setup..................................................................................... 26 outline dimensions ....................................................................... 27 ordering guide .......................................................................... 27 revision history revision 0: intitial version
ad8349 rev. 0 | page 3 of 28 specifications table 1. v s = 5 v; ambient temperature (t a ) = 25c; lo = C6 dbm; i/q inputs = 1.2 v p-p differential sine waves in quadrature on a 400 mv dc bias; baseband frequency = 1 mhz; lo source and rf output load impedances are 50 ?, unless otherwise noted. parameter conditions min typ max unit operating frequency 700 2700 mhz lo = 900 mhz output power 1.5 4 6 dbm output p1 db 7.6 dbm carrier feedthrough C45 C30 dbm sideband suppression C35 C31 dbc third harmonic 1 p out C (f lo + (3 f bb )), p out = 4 dbm C39 C36 dbc output ip3 f1 bb = 3 mhz, f2 bb = 4 mhz, p out = -4.2 dbm 21 dbm quadrature error 1.9 degree i/q amplitude balance 0.1 db noise floor 20 mhz offset from lo, all bb in puts at a bias of 400 mv C155 dbm/hz 20 mhz offset from lo, bb inputs = 1.2 v p- p differential on 400 mv dc C150 dbm/hz gsm sideband noise lo = 884.8 mhz, 6 mhz offset from lo, p out = 2 dbm C152 dbc/hz lo = 1900 mhz output power 0 3.8 6 dbm output p1db 6.8 dbm carrier feedthrough C38 dbm sideband suppression C40 C36 dbc third harmonic 1 p out C (f lo + (3 f bb )), p out = 3.8 dbm C37 C36 dbc output ip3 f1 bb = 3 mhz, f2 bb = 4 mhz, p out = C4.5 dbm 22 dbm quadrature error 0.7 degree i/q amplitude balance 0.1 db noise floor 20 mhz offset from lo, all bb in puts at a bias of 400 mv C156 dbm/hz 20 mhz offset from lo, bb inputs = 1.2 v p- p differential on 400 mv dc C150 dbm/hz gsm sideband noise lo = 1960 mhz, 6 mhz offset from lo, p out = 2 dbm C151 dbc/hz lo = 2140 mhz output power C2 +2.4 +5.1 dbm output p1db 5.6 dbm carrier feedthrough C42 C30 dbm sideband suppression C43 C36 dbc third harmonic 1 p out C (f lo + (3 f bb )), p out = 2.4 dbm C37 C36 dbc output ip3 f1 bb = 3 mhz, f2 bb = 4 mhz, p out = C6.5 dbm 19 dbm quadrature error 0.3 degree i/q amplitude balance 0.1 db noise floor 20 mhz offset from lo, all bb in puts at a bias of 400 mv C156 dbm/hz 20 mhz offset from lo, bb inputs = 1.2 v p- p differential on 400 mv dc C151 dbm/hz wcdma noise floor lo = 2140 mhz. 30 mhz offset from lo, p chan = C17.3 dbm C156 dbm/hz lo inputs pins loip and loin lo drive level characterization performed at typical level C10 C6 0 dbm nominal impedance 50 ? input return loss drive via 1:1 balun, lo = 2140 mhz C8.6 db baseband inputs pins ibbp, ibbn, qbbp, qbbn i and q input bias level 400 mv input bias current 11 a input offset current 1.8 a bandwidth (0.1 db) lo = 1500 mhz, baseband input = 600 mv p-p sine wave on 400 mv dc 10 mhz lo = 1500 mhz, baseband input = 60 mv p-p sine wave on 400 mv dc 24 mhz bandwidth (3 db) lo = 1500 mhz, baseband input = 600 mv p-p sine wave on 400 mv dc 160 mhz lo = 1500 mhz, baseband input = 60 mv p-p sine wave on 400 mv dc 340 mhz
ad8349 rev. 0 | page 4 of 28 parameter conditions min typ max unit output enable pin enop off isolation enop low C78 C50 dbm turn-on settling time enop low to high (90% of envelope) 20 ns turn-off settling time enop high to low (10% of envelope) 50 ns enop high level (logic 1) 2.0 v enop low level (logic 0) 0.8 v power supplies pins vps1 and vps2 voltage 4.75 5.25 v supply current enop = high 135 150 ma enop = low 130 145 ma 1 the amplitude of the third harmonic relative to the single sideband power decreases with decreasing baseband drive level (see figure 19, figure 20, and figure 21).
ad8349 rev. 0 | page 5 of 2 8 absolute maximum ra tings table 2. ad83 49 absolute maximum ratings p a r a m e t e r r a t i n g supply voltage vpos 5.5 v ibbp, ibbn, qbb p , qbbn 0 v, 2.5 v loip and loin 10 dbm internal power dissipation 800 mw ja (exposed paddle soldered down) 30c/w maximum junction temperature 125c operating temperature range ?40c to +85c storage temperature range ?65c to +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 . esd caution esd (electrostatic discharge) sensitive device. ele c tros tatic charg e s as high as 4000 v readily accumulate on the human body and test eq uipment and can discharge wi thout detection. although this product features proprietary esd protection circu i try, permanent dama ge may occur on devices subjected to high energy electrostatic discharges. theref ore, prop er esd precautions a r e recommended to avoid perform a nce degradation or l o ss of functiona l ity.
ad8349 rev. 0 | page 6 of 2 8 pin conf igura t ion and fu nctional descri ptions ad8349 top view (not to scale) ibbp 1 ibbn 2 com1 3 com1 4 loin 5 qbbp qbbn com3 com3 vps2 15 14 13 12 loip 6 vps1 7 enop 8 vout com3 com2 11 10 9 16 03570-0-002 fi g u r e 2 ta ble 3. pi n f u nct i on d e s c ri pt i o ns pin o. mnemonic description equivalent circuit 1, 2, 15, 16 ibbp, ibbn, qbbn, qbbp differential in-phase and quadr a ture baseba n d in puts. these hi gh impedance i n puts must be dc-biased to approxim ately 400 mv dc, and must be driven from a low impedance source. nominal characterized ac signal swing is 600 m v p-p on each pi n (100 mv to 70 0 mv). this results in a differential drive of 1.2 v p-p with a 400 mv dc bias. these inputs are not self-bi a sed and must be external ly biased. circuit a 3, 4 com1 common pin for lo phase splitte r and lo buffers. com1, com2, and com3 should all be connected to a ground plane vi a a low im peda nce path. 5, 6 loin, loip differential loca l osci llator in puts. internally d c -biased to appr o x imately 1.8 v when v s = 5.0 v. pins must be ac-coupled. sing le -ended drive is poss i ble with degradation in per f ormance. circuit b 7 v p s 1 positive supply voltage (4.75 v to 5.25 v) for th e lo bias-ce ll and buffer. vps1 an d vps2 should be conne cted to the same sup p ly. t o ensure a d equate external bypa ssing, co nnect 0.1 f and 100 pf capacitors between vps 1 and ground. 8 e n o p output enable. this pin can be us ed to enable or disable the r f output. connect to high logic level for n o rmal operatio n . conn ect to low logic level to disab l e o utput. circuit c 9 c o m 2 common pin for the output amplif ier. com1, com2, and com3 s h oul d al l be connected to a ground plane vi a a low im peda nce path. 10, 13, 14 com3 common pin for input v-to-i co n verters and mix e r cores . com1, com2, and c o m3 s h oul d al l be conne cted to a ground plan e via a lo w impe d ance path. 1 1 v o u t device output. single-ended, 50 ? internally bias ed rf output. pin must be ac-coupled to the load . circuit d 1 2 v p s 2 positive supply voltage (4.75 v to 5.25 v) for th e baseb and input v-to-i converters, mixer core, band gap reference, and output amplifer. vps 1 and vps2 should be connecte d to the same supply. to ensur e adequate external bypassi ng , connect 0.1 f and 100 pf capacitors between vps2 and groun d .
ad8349 rev. 0 | page 7 of 2 8 equiv a lent ci rcuits vps2 ibbp com3 03570-0-003 fi g u r e 3 . c i r c u i t a vps1 loin loip c om1 03570-0-004 fi g u r e 4 . c i r c u i t b 04500-0-005 vps2 enop com3 f i gure 5. cir c uit c 03570-0-006 40 ? 40 ? vout com2 vps2 fi g u r e 6 . c i r c u i t d
ad8349 rev. 0 | page 8 of 2 8 typical perf orm ance cha r acte ristics ?4 ?2 0 ?1 ?3 2 1 s s b outp ut p o we r (dbm) 4 3 6 5 8 7 700 900 1100 1300 1500 1700 1900 2100 2300 2500 2700 lo frequency (mhz) 03570-0-007 v s = 4.75v v s = 5.25v v s = 5v f i gure 7. s i ngle s i d e band (s sb) o u tpu t p o w e r (p ou t ) vs . l o f r equenc y (f lo ) (i and q inputs d r iv en in q u adr a ture at baseband f r equ e nc y (f bb ) = 1 m h z, i and q inputs at 1. 2 v p -p d i fferential , t a = 2 5 c ) ?10 ?9 ?7 ?3 ?1 1 ?5 ?8 ?4 ?2 0 ?6 outp ut p o we r v ariation (db) 03570-0-008 baseband frequency (mhz) 1 1 0 1000 100 600mv p-p 60mv p-p f i gure 8. i and q in put bandw i dth n o rmaliz ed t o g a in @ 1 mh z (f lo = 1 5 00 m h z, t a = 2 5 c ) 0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 s s b outp ut p o we r (dbm) ? 4 0 ? 3 0 ? 2 0 ? 1 0 0 1 02 03 04 0 temperature ( c) 60 50 70 80 03570-0-009 v s = 5v v s = 5.25v v s = 4.75v f i gure 9. ssb p ou t v s . t e mper ature (f lo = 2 1 40 m h z, f bb = 1 mh z, i and q input s d r iven in q u adr a t u r e at 1. 2 v p - p d i f f e rent i a l) ?4 ?3 ?1 3 5 7 8 10 1 ?2 2 4 6 0 1db ou tpu t c o m p r ession ( d b m ) 9 700 900 1100 1300 1500 1700 1900 2100 2300 2500 2700 lo frequency (mhz) 03570-0-010 t = +85 c t = +25 c t = ? 40 c f i g u re 10. ssb o u t p ut 1 db co mpres s i on p o int (o p1d b ) v s . f lo (f bb = 1 m h z, i and q inputs d r iv en in q u adr a ture at 1.2 v p -p d i ffer e ntial , t a = 25 c ) ?60 ?55 ?50 ?45 ?40 ?35 ?30 ?25 ?20 ?15 ?10 carrie r fe e d through (dbm) 700 900 1100 1300 1500 1700 1900 2100 2300 2500 2700 lo frequency (mhz) 03570-0-011 v s = 5v v s = 4.75v v s = 5.25v f i gure 11. car r i e r f eedthroug h v s . f lo (f bb = 1 m h z, i a n d q inputs d r ive n i n q u adr a t u re at 1. 2 v p -p d i f f e rent i a l , t a = 2 5 c ) ?5 0 ?4 8 ?4 6 ?2 0 carrie r fe e d through (dbm) ?4 4 ?4 2 ?4 0 ?3 8 ?3 6 ?3 4 ?3 2 ?3 0 ?2 8 ?2 6 ?2 4 ?2 2 ? 4 0 ? 3 0 ? 2 0 ? 1 0 0 1 02 03 04 0 temperature ( c) 60 50 70 80 03570-0-012 v s = 5v v s = 5.25v v s = 4.75v f i gure 12. car r i e r f eedthroug h v s . t e mpe r atu r e (f lo = 21 40 m h z , f bb = 1 m h z, i and q inputs d r iv en in q u adr a ture at 1.2 v p -p d i ffer e ntial , t a = 25 c )
ad8349 rev. 0 | page 9 of 2 8 sideband suppression (dbc) ?60 ?55 ?50 ?45 ?40 ?35 ?30 ?25 ?20 ?15 ?10 700 900 1100 1300 1500 1700 1900 2100 2300 2500 2700 lo frequency (mhz) 03570-0013 v s = 5v v s = 4.75v v s = 5.25v f i gure 13. sid e ban d sup p ression vs. f lo (f bb = 1 m h z, i an d q inputs d r iven in q u ad r a t u r e at 1 . 2 v p -p d i f f e r e nt i a l , t a = 2 5 c ) ?60 ?55 ?50 ?45 ?40 ?35 ?30 ?25 ?20 ?15 ?10 s i de band s u p p r e s s i on (dbc ) baseband frequency (mhz) 1 1 0 100 03570-0-014 v s = 5v v s = 5.25v v s = 4.75v f i gure 14. sid e ban d sup p ression vs. f bb (f lo = 21 40 m h z , i a n d q inputs d r iven in q u ad r a t u r e at 1 . 2 v p -p d i f f e r e nt i a l , t a = 2 5 c ) ?60 ?55 ?50 ?45 ?40 ?35 ?30 sideband suppression (dbc) ? 4 0 ? 3 0 ? 2 0 ? 1 0 0 1 02 03 04 0 temperature ( c) 60 50 70 80 03570-0-015 v s = 5v v s = 5.25v v s = 4.75v f i gure 15. sid e ban d sup p ression vs. t e mper atur e (f lo = 21 40 m h z , f bb = 1 m h z, i and q inputs d r iv en in q u adr a ture 1.2 v p -p d i fferential) third orde r dis t ortion (dbc ) ?60 ?55 ?50 ?45 ?40 ?35 ?30 ?25 ?20 ?15 ?10 700 900 1100 1300 1500 1700 1900 2100 2300 2500 2700 lo frequency (mhz) 03570-0016 v s = 5v v s = 4.75v v s = 5.25v f i gure 16. thir d o r der d i st or tion vs . f lo (f bb = 1 m h z, i an d q inputs d r iven in q u ad r a t u r e at 1 . 2 v p -p d i f f e r e nt i a l , t a = 2 5 c ) ?60 ?55 ?50 ?45 ?40 ?35 ?30 ?25 ?20 ?15 ?10 third orde r dis t ortion (dbc ) baseband frequency (mhz) 1 1 0 100 03570-0-017 v s = 5v v s = 5.25v v s = 4.75v f i gure 17. thir d o r der d i st or tion vs . f bb (f lo = 21 40 m h z , i a n d q inputs d r iven in q u ad r a t u r e at 1 . 2 v p -p d i f f e r e nt i a l , t a = 2 5 c ) ?60 ?55 ?50 ?45 ?40 ?35 ?30 third orde r dis t ortion (dbc ) ? 4 0 ? 3 0 ? 2 0 ? 1 0 0 1 02 03 04 0 temperature ( c) 60 50 70 80 03570-0-018 v s = 5v v s = 5.25v v s = 4.75v f i gure 18. thir d o r der d i st or tion vs . t e mper atur e (f lo = 21 40 m h z , f bb = 1 m h z, i a n d q inputs d r ive n i n q u adr a ture at 1. 2 v p -p d i fferenti a l)
ad8349 rev. 0 | page 10 of 28 ?70 ?60 ?50 ?55 ?65 ?40 ?45 ?30 ?35 ?20 ?25 ?10 ?15 ?14 ?10 ?6 ?8 ?12 ?2 ?4 2 0 6 4 10 8 0.2 0.4 0.6 0.8 1.0 1.4 2.4 1.2 1.6 1.8 2.0 2.6 2.8 3.0 baseband differential input voltage (v p-p) 2.2 03570-0-019 ssb, dbm 3usb, dbc usb, dbc lo, dbm f i gure 19. thi r d o r der d i s t o r ti on ( 3 us b), car r i e r f eedth r o ugh, s i deb a nd sup p r e ssi o n , and ssb p ou t vs . ba se ba nd di ffe r e ntia l input l e v e l (f lo = 90 0 mhz, f bb = 1 mhz , i and q in puts d r iven in q u adr a ture , t a = 25 c ) ?70 ?60 ?50 ?55 ?65 ?40 ?45 ?30 ?35 ?20 ?25 ?10 ?15 ?14 ?10 ?6 ?8 ?12 ?2 ?4 2 0 6 4 10 8 0.2 0.4 0.6 0.8 1.0 1.4 2.4 1.2 1.6 1.8 2.0 2.6 2.8 3.0 baseband differential input voltage (v p-p) 2.2 03570-0-020 lo, dbm usb, dbc 3usb, dbc ssb, dbm f i gure 20. thi r d o r der d i s t o r ti on ( 3 us b), car r i e r f eedth r o ugh, s i deb a nd sup p r e ssi o n , and ssb p ou t vs . ba se ba nd di ffe r e ntia l input l e v e l (f lo = 1 9 0 0 m h z, f bb = 1 m h z, i and q i n puts d r iven in q u adr a ture , t a = 25 c ) ?70 ?60 ?50 ?55 ?65 ?40 ?45 ?30 ?35 ?20 ?25 ?10 ?15 ?14 ?10 ?6 ?8 ?12 ?2 ?4 2 0 6 4 10 8 0.2 0.4 0.6 0.8 1.0 1.4 2.4 1.2 1.6 1.8 2.0 2.6 2.8 3.0 baseband differential input voltage (v p-p) 2.2 03570-0-021 ssb, dbm 3usb, dbc lo, dbm usb, dbc f i gure 21. thi r d o r der d i s t o r ti on ( 3 us b), car r i e r f eedth r o ugh, s i deb a nd sup p r e ssi o n , and ssb p ou t vs . ba se ba nd di ffe r e ntia l input l e v e l (f lo = 2 1 40 m h z, f bb = 1 m h z, i and q inputs d r iven in q u adr a ture , t a = 25 c ) 110 115 120 125 130 135 160 s u p p l y curre nt (ma) 140 145 150 155 ? 4 0 ? 3 0 ? 2 0 ? 1 0 0 1 02 03 04 0 temperature ( c) 60 50 70 80 03570-0-022 v s = 5v v s = 5.25v v s = 4.75v f i gure 22. p o wer s u p p ly cu rrent v s . t e mper atur e 03570-0023 500 ? 200 ? no termination f i g u re 23. sm it h ch ar t of l o i p p o r t s 11 (l oin p i n a c - c oupled to g r ound) c u r v es with b a lu n and ex tern al t e r m in ation resi st o r s a l so sho wn ( t a = 25 c ) 03570-0-024 ?4 0 ?3 5 ?3 0 ?2 5 ?2 0 ?1 5 re turn los s (db) ?1 0 ?5 0 700 900 1100 1300 1500 1700 1900 2100 2300 2500 2700 frequency (mhz) v s = 5v f i gure 24. r e turn l o s s ? s 22 ? of v ou t ou t p u t ( t a = 25 c )
ad8349 rev. 0 | page 11 of 28 0 2 4 6 22 24 26 28 30 20 8 10 12 14 16 18 p e rce ntage ?157.0 ?155.5 ?155.0 ?154.5 ?154.0 ?153.5 ?153.0 ?156.0 ?156.5 noise floor (dbm/hz) f lo = 900mhz 03570-0-025 f i gure 25. 2 0 m h z o ffset no is e flo o r d i s t ribut i on at f lo = 900 mh z (i and q input s at a bi as of 40 0 mv , t a = 2 5 c ) 0 2 4 6 22 24 26 28 30 p e rce ntage 20 8 10 12 14 16 18 ?158.0 ?156.5 ?156.0 ?155.5 ?155.0 ?154.5 ?154.0 ?157.0 ?157.5 noise floor (dbm/hz) 03570-0-026 f lo = 1900mhz f i gure 26. 2 0 m h z o ffset no is e flo o r d i s t ribut i on at f lo = 1 9 00 m h z (i and q input s at a bi as of 40 0 mv , t a = 2 5 c ) 0 2 4 6 22 24 26 28 30 p e rce ntage 20 8 10 12 14 16 18 ?159.0 ?157.5 ?157.0 ?156.5 ?156.0 ?155.5 ?155.0 ?158.0 ?158.5 noise floor (dbm/hz) 03570-0-027 f lo = 2140mhz f i gure 27. 2 0 m h z o ffset no is e flo o r d i s t ribut i on at f lo = 2 1 40 m h z (i and q input s at a bi as of 40 0 mv , t a = 2 5 c ) 0 2 4 6 8 10 12 14 16 18 20 p e rce ntage ? 152.0 ? 151.5 ? 151.0 ? 150.5 ? 150.0 ? 149.5 ? 149.0 ? 148.5 ? 148.0 ? 147.5 ? 147.0 noise floor (dbm/hz) f lo = 940mhz 03570-0-028 f i gure 28. 2 0 m h z o ffset no is e flo o r d i s t ribut i on at f lo = 940 mh z (f bb = 1 m h z, i and q inputs d r ive n i n q u adr a ture at 1. 2 v p - p , t a = 25 c ) 0 2 4 6 8 10 12 14 16 18 28 p e rce ntage ?152.5 ?151.5 ?151.0 ?150.5 ?150.0 ?149.5 ?149.0 ?148.5 ?152.0 ?148.0 noise floor (dbm/hz) 03570-0-029 24 22 26 20 f lo = 1960mhz f i gure 29. 2 0 m h z o ffset no is e flo o r d i s t ribut i on at f lo = 1 9 60 m h z (f bb = 1 m h z, i and q inputs d r ive n i n q u adr a ture at 1. 2 v p - p , t a = 25 c ) 0 2 4 6 22 24 26 28 30 20 8 10 12 14 16 18 p e rce ntage ? 153.0 ? 151.5 ? 151.0 ? 150.5 ? 150.0 ? 149.5 ? 149.0 ? 152.0 ? 152.5 noise floor (dbm/hz) 03570-0-030 f lo = 2140mhz f i gure 30. 2 0 m h z o ffset no is e flo o r d i s t ribut i on at f lo = 2 1 40 m h z (f bb = 1 m h z, i and q inputs d r ive n i n q u adr a ture at 1. 2 v p - p , t a = 25 c )
ad8349 rev. 0 | page 12 of 28 ? 160 ? 158 ? 154 ? 146 ? 142 ? 140 ? 150 ? 156 ? 148 ? 144 ? 152 nois e floor (dbm/hz) lo input (dbm) ?10 2 03570-0-031 ? 8 ?6 ?4 ? 2 0 without ac input with ac input f i gure 31. 2 0 m h z o ffset noise flo o r v s . l o input p o wer (f lo = 2 1 40 m h z, t a = 2 5 c ) ?60 ?50 ?40 ?45 ?55 ?30 ?35 carrie r fe e d through (dbm) ?20 ?25 ?10 ?15 ?6 ?4 ?10 ? 8 ? 2 0 2 lo input (dbm) 03570-0032 f lo = 2140mhz f lo = 900mhz f lo = 1900mhz f i gure 32. car r i e r f eedthroug h v s . l o i n put p o wer (f bb = 1 mh z, i a n d q input s d r iven in q u adr a t u r e at 1. 2 v p - p d i f f e rent i a l , t a = 25 c ) ?60 ?50 ?40 ?45 ?55 ?30 ?35 sideband suppression (dbc) ?25 ?20 ?10 ?15 ?6 ?4 ?10 ? 8 ? 2 0 2 lo input (dbm) 03570-0033 f lo = 2140mhz f lo = 900mhz f lo = 1900mhz f i gure 33. sid e ban d sup p ression vs. l o input p o w e r (f bb = 1 mh z , i and q input s d r iven in q u adr a t u r e at 1. 2 v p - p d i f f e rent i a l , t a = 25 c ) 0 5 10 15 20 25 30 35 p e rce ntage ?0 . 1 0 0 ?0. 1 2 5 ? 0 . 1 75 ?0 . 1 5 0 ?0 . 2 0 0 ?0. 0 7 5 ? 0 . 0 50 ?0. 0 2 5 0 magnitude imbalance (db) 03570-0-034 f i gure 34. i and q i n puts q u adr a ture p h ase i m balanc e d i stribution (f lo = 21 40 m h z , f bb = 1 m h z, i and q i n puts d r iven in q u ad r a t u r e at 1 . 2 v p -p d i f f e rent i a l , t a = 2 5 c ) 0 5 10 15 20 25 30 35 p e rce ntage 0.50 0.75 0 0.25 1.00 1.25 1.50 phase (i-q) imbalance (degrees) 03570-0-035 f i gure 35. i and q i n puts a m plitud e i m balanc e d i strib u tion (f lo = 2 1 40 m h z, f bb = 1 m h z, i and q inputs d r iven in q u ad r a t u r e at 1 . 2 v p -p d i f f e rent i a l , t a = 2 5 c ) 0 5 10 15 20 25 30 35 p e rce ntage op1db (dbm) 5.0 4.5 5.5 6.0 6.5 03570-0-036 f i g u re 36. op 1db d i s t ribut i on. (f lo = 21 40 m h z , f bb = 1 m h z, i and q inputs d r iven in q u ad r a t u r e at 1 . 2 v p -p d i f f e r e nt i a l , t a = 2 5 c )
ad8349 rev. 0 | page 13 of 28 0 5 10 15 20 25 30 35 40 p e rce ntage ?60 ? 45 ?40 ? 35 ? 3 0 ? 25 carrier feedthrough (dbm) ?55 ? 50 03570-0-040 f lo = 1900mhz f i gure 37. car r i e r f eedthroug h d i s t r i b u tion at f lo = 1 9 00 m h z (f bb = 1 m h z, i and q inputs d r iv en i n q u adr a ture a t 1.2 vp -p , t a = 2 5 c ) carrier feedthrough (dbm) p e rce ntage 24 22 20 18 16 14 12 10 8 6 4 2 0 ?70 ? 65 ?60 ? 55 ?50 ? 45 ?40 ? 35 ? 3 0 03570-0-041 f lo = 2140 mhz f i gure 38. car r i e r f eedthroug h d i s t r i b u tion at f lo = 2 1 40 m h z (f bb = 1 m h z, i and q inputs d r iven in q u adr a ture at 1.2 v p - p , t a = 25 c ) 0 2 4 6 8 10 12 14 16 18 20 p e rce ntage ?80 ? 70 ?60 ? 50 ? 4 0 ? 30 carrier feedthrough (dbm) 03570-0-039 f lo = 900mhz f i gure 39. car r i e r f eedthroug h d i s t r i b u tion at f lo = 9 0 0 mh z. (f bb = 1 m h z, i and q i n put s d r ive n in q u ad r a t u r e at 1.2 v p - p , t a = 25 c ) 0 5 10 15 20 25 30 35 p e rce ntage ?7 0 ?65 ? 60 ?55 ? 50 ?45 carrier feedthrough (dbm) after nulling to < ? 65dbm at +25 c t = ? 40 c t = +85 c 03570-0-037 f i gure 40. car r i e r f eedthrou g h d i str i b u tion at t e m p er atu r e e x trem es, af ter carr ie r f e edthro ugh nul l ed to < - 6 5 d b m at t a = 25 c. (f lo = 21 40 m h z , i and q input s at a bias of 4 0 0 mv ) p e rce ntage 0 4 8 12 16 20 24 30 2 6 10 14 18 22 28 26 ?75 ?6 5 ? 6 0 ?5 5 ? 5 0 ?35 sideband suppression (dbc) after nulling to < ? 50dbc at +25 c ?7 0 ? 4 0 ?45 03570-0-038 t = ? 40 c t = +85 c f i gure 41. sid e ban d sup p ressio n d i str i buti on at t e mpe r a t ur e e x trem es, af te r s i d e ba n d s u pp r e s s i o n n u ll e d t o < -50 d b c a t t a = 25 c. (f lo = 2 1 40 m h z, f bb = 1 m h z, i and q inputs biased at 0.4 v )
ad8349 rev. 0 | page 14 of 28 circuit description ove r vi e w the ad8349 can b e divided in to f i v e s e c t io n s : t h e lo c a l os cil- l a tor ( l o ) i n te r f a c e, t h e b a s e b a nd volt ag e - to - c u r re n t ( v - t o - i ) co n v er t e r , t h e mixers, t h e dif f er en t i al-t o-si n g le-e n d e d (d -t o-s) a m plif ier , a nd t h e b i as cir c ui t. a det a i l e d b l o c k d i a g r a m o f t h e de vice is sh own in f i gur e 42. ph a s e s p l i tte r ou t loip loin i bbp i bbn q bbp q bbn 03570-0-043 f i gur e 4 2 . ad83 49 bl oc k dia g r a m the l o in t e r f ac e g e n e r a t e s tw o l o sig n als a t 90 deg r e e s o f phas e dif f er en c e t o dr i v e tw o mixers in q u adr a t u r e . b a s e b a nd sig n als a r e co n v er t e d in t o c u r r e n ts b y t h e v - t o - i co n v er t e rs, w h ich fe e d i n t o t h e tw o mixers. the o u t p u t s o f t h e mixers co m b i n e t o fe e d t h e dif f er en t i al -t o-sin g le -e n d e d a m pl if ier , w h ich p r o v ides a 50 ? o u t p ut i n t e r f ace . refer e n c e c u r r en ts t o e a ch s e c t ion a r e gen e r a te d b y t h e b i as cir c ui t. a ddi t i ona l ly , t h e rf o u t p u t is con t r o l l ed b y a n ou t p u t ena b le p i n (en o p), which i s c a p a bl e of s w itch i n g t h e output on a n d of f w i t h i n 5 0 ns . a det a i l e d des c r i pt io n o f e a ch s e c t io n fol l o w s. lo i n t e r f a c e the l o i n t e r f ac e co n s is ts o f in terle a v e d s t a g e s o f b u f f er a m plif iers an d p o l y phas e phas e s p li t t ers. an in p u t b u f f er p r o v ides a 50 ? t e r m ina t ion t o t h e lo sig n a l s o ur ce dr i v ing loi p and loi n . t h e b u f f e r a l s o inc r e a s e s t h e lo s i g n a l a m pli t ude t o dr i v e t h e phas e s p li t t e r . the phas e s p li t t e r is fo r m e d b y a n r - c p o l y phas e netw o r k t h a t s p li ts t h e b u f f er e d l o sig n al in t o tw o p a r t s in p r e c is e q u adra t u r e phas e r e l a tion wi t h each o t her . e a c h l o sig n al th en p a s s es thro ug h a b u f f er a m p l i f i e r t o co m p en sa t e f o r th e si gn al los s th r o ugh th e p h a s e spl i tte r . t h e t w o s i g n a l s p a ss t h rou g h anot he r p o ly phas e n e tw o r k t o enha n c e t h e q u adra t u r e acc u rac y o v er t h e f u l l op e r a t i n g f r e q u e nc y r a nge. t h e output s of t h e s e c o n d ph a s e s p li t t e r a r e fe d i n t o t h e dr i v er am plif iers fo r t h e mixers l o in p u ts. v- t o - i co n v e r t e r the dif f er en t i al b a s e b a nd in p u t v o l t a g es t h a t a r e a p plie d t o t h e b a s e b a nd in p u t p i n s a r e fe d to t w o o p a m ps t h a t p e r f o r m a dif f er en t i al v o l t a g e- t o -c ur r e n t c o n v ersio n . the dif f er en t i al output c u r r e n t s of t h e s e op a m p s t h e n f e e d e a c h of t h e i r re sp e c t i ve m i x e r s . mixers the ad8349 has tw o do ub le-ba l an ce d mixers, o n e f o r the in- phas e chan nel ( i chan nel ) and one for t h e q u a d r a t u re chan nel (q cha nnel). b o t h mixers a r e b a s e d on t h e gi lb er t cel l desig n of fo ur cr os s-co nne c t e d tran sis t o r s. th e ou t p u t c u r r en ts f r o m th e tw o mixers sum t o get h er in a p a ir o f r e sist o r -ind uc t o r (r -l) lo ads. th e sig n a l s de v e l o p e d acros s th e r - l lo ads a r e s e n t t o th e d-t o -s am plif ie r . d - t o -s amplifier the o u t p u t d-to-s a m plif ier con s ists o f tw o em i t t e r fol l o w ers dr iv i n g a tote m p o l e out p ut st ag e. o u t p ut i m p e da nc e i s e s t a b - lis h e d b y the e m i t t e r r e sis t o r s in t h e o u t p u t tr a n sis t o r s. th e output of t h i s st age c o n n e c t s to t h e output ( v ou t ) pi n . bias cir c uit a b a nd g a p re f e re nc e c i rc u i t ge ne r a te s t h e pro p or t i on a l - t o - ab s o lute - t e m p e r a tu re ( p t a t ) r e f e re nc e c u r r e n t s u s e d by dif f er en t s e c t ion s . th e b a nd ga p r e fer e n c e cir c ui t als o g e n e r a tes a t e m p era t ur e st a b le c u r r en t in t h e v - t o -i con v e r t e rs t o p r o d uce a t e m p era t ur e i n de p e n d e n t s l e w ra t e . outpu t en able du ri n g n o rm al o p e r a t i o n ( e n o p = h i gh ) , th e o u t p u t cu rr e n t f r om t h e v - to - i c o n v e r te rs fe e d s i n to t h e m i xe rs , w h e r e t h e y mix wi th t h e two p h as es o f l o sig n als. w h en en o p is p u l l ed lo w , t h e v - t o -i o u t p ut c u r r en ts ar e s t e e r e d a w a y f r o m t h e m i x e r s , th us t u rn i n g o f f th e r f o u t p u t . p o w e r t o th e f i n a l s t a g e o f lo dr i v ers is a l s o r e m o ve d to minim i ze lo fe e d t h r o ug h. e v en w h e n t h e o u t p ut is dis a b l e d , t h e dif f er en t i al- t o-sin g le - en d e d st a g e is st i l l p o w e r e d u p to ma in t a in con s t a n t o u t p u t im p e d a n c e .
ad8349 rev. 0 | page 15 of 28 basic connections p o we r of t h e output s i g n a l i s a t l e a s t a c r e s t f a c t or b e l o w t h e ad8349 s ou t p u t co m p r e s s ion p o in t. ref e r t o the a p p l ic a t io n s s e c t io n fo r dr i v e-le ve l co n s ider a t io n s in w c dma an d gs m/ed ge sys t em s. the b a sic co nne c t i o n s fo r o p era t in g t h e a d 83 49 a r e s h own i n f i gur e 43. a sing le p o w e r s u p p l y o f betw een 4. 75 v a nd 5.25 v is a p plie d to p i ns vps1 an d vps 2 . a p a ir o f es d p r o t e c t i o n dio d es co n n e c t in ter n a l ly b e tw e e n vps1 and v p s2, s o t h es e m u s t be ti e d t o th e sa m e po t e n t i a l . b o th p i n s sh o u ld be indivi d u a l ly de c o u p le d usin g 10 0 pf a n d 0.1 f ca p a c i to rs to g r o u n d . th es e c a p a ci t o rs sh o u l d b e lo c a t e d as clos e as p o s s i b le to t h e d e v i c e . for nor m a l op e r a t i o n , t h e output e n abl e pi n , e n o p , m u s t b e p u l l e d h i g h . t h e t u r n - o n t h r e s h o l d f o r e n o p i s 2 v . p i n s co m1 , co m2, a nd c o m3 s h o u ld al l be tied t o t h e s a me g r o u nd pl a n e t h r o ug h lo w im p e dan c e p a t h s. re d u cin g t h e b a s e b a n d dr i v e le v e l als o has t h e b e n e f i t o f in cr e a si n g t h e b a ndwid t h o f t h e b a s e b a nd in p u t . this w o u l d a l lo w t h e a d 83 49 t o b e us e d in a p plic a t io ns r e q u ir in g a hi g h m o du l a t i o n b a n d w i dt h , e . g . , a s t h e i f m o du l a t o r i n h i g h d a t a - ra t e micr o w a v e rad i os. single-ended baseba nd drive w h er e o n l y sing le-e n d e d i an d q sig n als a r e a v a i la b l e , a dif f er en tial a m plif ier , s u c h as the ad8132 o r ad8138, ca n be us e d t o g e n e ra te t h e r e q u ir e d dif f er en t i al dr i v e sig n al fo r t h e ad8349. baseband i and q i n p u t s the i an d q i n pu ts sh o u ld b e dr i v en dif f er en t i al l y . th e typ i c a l dif f er en t i a l dr i v e le vel (as us e d fo r cha r ac t e r i za t i o n m e asur e - m e n t s) fo r th e i a nd q bas e b a n d sig n als is 1.2 v p-p , which is eq ui valen t t o 60 0 mv p-p on eac h bas e b a n d in p u t. th e b a s e - ba nd in p u ts ha ve t o be exter n al l y b i as ed t o a leve l betw e e n 400 mv an d 50 0 mv . t h e op t i m u m l e vel fo r t h e b e st p e r f o r - ma nce is 400 mv . th e r e co mmen ded dr i v e leve l o f 1.2 v p-p do es n o t i n di c a te a max i m u m d r i v e le vel. i f o p e r a t io n clo s er to co m p r e ssio n is desir e d , t h e 1.2 v p-p dif f er en t i a l limi t can b e e x ceed ed . f i gur e 44 s h o w s a n exa m p l e o f a cir c ui t tha t con v er ts a g r o u n d - r e fer e n c e d , sin g le-ende d sig n a l to a dif f er en t i a l sig n a l , a nd adds th e r e q u ir e d 40 0 mv b i as v o l t ag e . t h e b a s e b a nd i n put s c a n a l s o b e d r ive n w i t h a s i ng l e - e nd e d sig n al b i as e d t o 400 mv , wi t h the un us ed in p u ts b i as e d t o 400 mv dc. this m o de o f o p era t io n is n o t r e commende d , h o w e v e r , b e c a us e a n y dc l e v e l di f f er en ce b e tw e e n t h e b i as l e v e l o f t h e dr i v e sig n al a nd t h e dc l e ve l o n t h e u n us e d in p u t ( i nclu d i ng t h e e f fe c t of te m p e r a t u r e d r i f t ) , c a n re su lt i n i n cr eased l o f e ed th r o ugh . a d di ti o n all y , th e m a xi m u m lo w d i stor t i on output p o we r w i l l b e re d u c e d by 6 d b . f o r ba se ba n d sign als w i t h a hi g h pea k - t o-a v e r a g e ra ti o (e .g., c d d a or w c dm a ) , t h e p e a k s i g n a l l e vel w i l l ha ve to b e b e l o w th e ad8349 s com p r e s s io n l e v e l in o r der t o p r even t c l i p p i ng o f th e si gn al peak s. cli p p i n g o f si g n al peak s in cr eases d i s t o r ti o n . i n t h e c a s e of c d m a a n d w c dm a i n put s , c l ippi ng re s u lt s i n an i n c r e a s e of s i g n a l l e a k age i n t o a d j a c e n t ch an nel s . in ge ne r a l, t h e b a s e b a nd dr i v e sh o u ld b e a t a le v e l w h er e t h e p e ak sig n al ibbp ibbn com1 com1 loin qbbp qbbn com3 com3 vps2 loip vps1 enop vout com3 com2 03570-0-044 16 15 14 13 12 11 10 9 1 2 3 4 5 6 7 8 a d 834 9 t1 etc1-1-13 1 5 3 2 4 100pf 0.1 f 100pf qp qn +v s vout 100pf 100pf +v s lo in ip 0.1 f 100pf 200 ? 200 ? f i gure 43. ad8349 basic c o nnec t ions
ad8349 rev. 0 | page 16 of 28 03570-0-045 a d 834 9 phase splitter loin loip vout vps1 vps2 ibbp ibbn qbbp qbbn 0.1 f 100pf 100pf 0.1 f 0.1 f 10 f 3 6 5 4 1 8 a d 813 2 2 i in 499 ? 499 ? 0.1 f +5v 499 ? 24.8 ? 49.9 ? 499 ? 10k ? 866 ? 10 f 0.1 f 3 6 5 4 1 8 a d 813 2 2 q in 499 ? 499 ? 0.1 f +5v 499 ? 24.9 ? 49.9 ? 499 ? + + com1 com2 com3 10 f 0.1 f + ?5v 10 f 0.1 f + ?5v f i gure 44. sing le -ended iq d r ive c i r c u i t l o inpu t drive le vel the lo cal os ci l l a t o r in p u ts a r e desig n e d t o b e dr i v en dif f er en- tial l y . th e de vic e is s p ecif ie d wi th a n lo dr i v e l e v e l o f C6 db m. this le ve l was ch os en t o p r o v id e t h e b e st n o is e p e r f o r ma n c e . i n cr e a si n g t h e lo dr i v e le vel de g r ades sideb a n d su p p r essio n a n d in cr ea se s ca rri e r f eed th r o ugh , wh ile im p r o v i n g n o i s e p e r f or manc e. r e d u c i ng t h e lo dr ive l e vel c r e a t e s t h e opp o s i te ef fe c t : im p r o v e d sideb a nd su pp r e ssio n an d r e d u ce d ca r r i er f eed th r o ugh . frequenc y r a nge the l o f r eq uenc y ra n g e is f r o m 700 mh z t o 27 00 mh z. th es e limi ts a r e def i n e d b y t h e na t u r e o f t h e l o phas e s p li t t e r cir c ui tr y . th e phas e s p l i t t e r g e nera t e s l o dr i v e sig n als fo r th e i n te r n a l m i x e r s , w h i c h are 9 0 d e g r e e s out of ph a s e f r om e a c h o t h e r . o u tside of th e s p ecif ied f r eq uen c y ra n g e (700 mh z t o 2700 mh z), this q u adr a t u r e acc u rac y deg r ades, r e s u l t in g in p o o r sideb a n d rej e c t io n p e r f o r ma nce. f i gur e 4 5 a nd f i gur e 46 sh o w t h e sideb a nd su p p r ession o f a ty p i ca l de vi ce o p er a t in g o u tside t h e sp e c if ie d lo f r e q ue n c y ra n g e . t h e l e v e l o f sideb a nd su p p r essio n an d deg r ad a t ion is a l s o inf l uen c e d b y ma n u fac- t u ri n g p r oc e s s va ri a t i o n s . l o inpu t im ped a nce m a t c hing sin g le-e nde d lo s o ur ces a r e t r a n sfo r m e d i n to a dif f er en t i a l sig n al via a 1:1 bal u n (et c 1-1 - 13). a 200 ? s h un t r e sis t o r t o gnd on each lo in p u t o n t h e de vice side o f th e ba l u n r e d u ces t h e r e t u r n los s fo r t h e l o i n p u t p o r t . b e ca us e t h e l o i n p u t pin s a r e in t e r n al l y dc -b ias e d , ac co u p lin g c a p a ci t o rs m u s t be us e d o n ea c h l o in p u t p i n . 03570-0-046 1.0 1.5 2.0 2.5 3.0 3.5 4.0 300 350 400 450 500 550 600 650 700 lo frequency (mhz) s s b outp ut p o we r (dbm) ?60 ?50 ?40 ?30 ?20 ?10 0 sideband suppression (dbc) ssb usb f i gure 45. sid e ban d sup p ression be low 700 mhz
ad8349 rev. 0 | page 17 of 28 03570-0-047 ?1 0 lo frequency (mhz) s s b outp ut p o we r (dbm) ?44 ?43 ?42 ?41 ?40 sideband suppression (dbc) usb ssb ?8 ?7 ?6 ?5 ?4 ?3 ?2 ?4 5 ?4 6 ?4 8 ?47 2700 2750 2800 2850 2900 2950 3000 f i gure 46. sid e ban d sup p ressio n ab ove 27 0 0 mh z single-ended l o dri v e the lo i n p u t c a n b e dr i v e n sing le-e n d e d a t t h e ex p e n s e o f h i gh e r l o f eed t h r o ugh a t m o s t f r eq ue n c i e s (see f i gur e 48). l o in is ac-co u p l ed t o g r o u nd , a nd l o ip is dr iv en thr o ug h a c o upl i ng c a p a c i tor f r om a s i ng l e - e nd e d 5 0 ? s o u r c e ( s e e f i g u re 47). a 400 ? s h un t r e sis t o r o n the sig n al-s o u r c e side o f th e ac co u p l i n g ca pa ci t o r w a s used f o r th e m e as ur em en t . ad8349 loin loip 5 6 lo 100pf 400 ? 100pf 03570-0-048 f i gure 47. s c he mat i c f o r s i ngle -ended l o d r ive ?60 ?55 ?50 ?45 ?40 ?35 ?30 ?25 ?20 ?15 ?10 carrier f eedt hrough ( d bm ) 700 900 1100 1300 1500 1700 1900 2100 2300 2500 2700 lo frequency (mhz) single-ended lo drive differential lo drive 03570-0-049 f i gure 48. l o f e edthr o u g h v s . f r eque n c y , single -ended vs. d i fferential l o d r ive ( s ing l e - s i deb a nd m o dul a t i on) rf output the rf o u t p u t is desig n e d t o dr i v e a 50 ? lo ad , b u t sh o u l d b e a c - c oupl e d , a s s h ow n i n f i g u re 4 3 , b e c a u s e of i n te r n a l d c b i asing. t h e rf o u t p ut im p e dance is clos e t o 50 ? a nd p r o v ides fa irly go o d r e t u r n loss o v er t h e sp e c if ie d o p er a t in g f r e q uen c y r a nge ( s e e f i g u r e 2 4 ) . a s a re su lt , no a d d i t i o n a l m a tch i ng cir c ui t r y is r e q u ir e d if t h e o u t p u t is dr i v in g a 5 0 ? lo ad . th e o u t p u t p o w e r o f th e ad8349 u nder n o minal con d i t io ns (1.2 v p-p dif f e r en tial bas e band dr i v e , 400 mv dc bas e band b i as, an d a 5 v su p p ly ) is sh o w n in f i gur e 7. outpu t en able the en op pin ca n b e us e d to tur n t h e rf o u t p u t o n and o f f. this p i n sh o u ld be h e l d hig h (g r e a t er tha n 2 v) f o r n o r m al o p era t ion. t akin g en o p lo w (les s tha n 800 mv) dis a b l es t h e output p o we r an d prov i d e s a n of f - i s o l a t i o n l e v e l of < C 5 0 d b m at t h e o u t p u t . f i gur e 49 a nd f i gur e 50 s h o w t h e enab le and dis a b l e tim e do ma in r e s p o n s e s o f th e en o p f u n c tion a t 900 mh z. t y p i cal ena b le and dis a b l e t i m e s a r e a p p r o x ima t ely 20 n s an d 50 n s , re sp e c t i vely . 03570-0-050 ?8 ?4 ?2 ?6 0 v en op (v ) 4 2 8 6 ?800 ?400 ?200 ?600 0 v vou t (mv ) 400 200 800 600 time (ns) 0 2 0 100 40 60 80 f i gur e 4 9 . enop ena b le ti me , 90 0 mh z 03570-0-051 ?8 ?4 ?2 ?6 0 v en op (v ) 4 2 8 6 ?800 ?400 ?200 ?600 0 v vou t (mv ) 400 200 800 600 time (ns) 0 2 0 100 40 60 80 f i g u re 50. e n op d i s a ble ti m e , 9 00 m h z.
ad8349 rev. 0 | page 18 of 28 baseband d a c in ter f a c e the r e co m m e nde d b a s e b a nd i n p u t s w in g and b i as le vels o f t h e ad8349 s dif f er en t i al bas e b a n d in p u ts al lo w f o r dir e c t co nne c t io n to m o st b a s e b a nd d a cs wi t h o u t t h e n e e d fo r an y e x t e rn al a c ti v e co m p o n en t s . t y p i call y th e s e d a c s h a v e a dif f er en t i al f u l l - s cale o u t p u t c u r r en t f r o m 0 ma t o 20 ma on e a ch dif f er en t i al o u t p ut. th es e c u r r en ts ca n b e e a si l y co n v er t e d t o v o l t a g es using g r o u n d -r efer e n ce d sh un t r e sis t o r s. m o s t b a s e b a n d d a c s for t r ans m i t ch ai ns are d e s i g n e d w i t h t w o d a cs in a sin g l e p a c k a g e . ad9777 interf a c e the ad977x famil y o f d u al d a cs is w e l l s u i t e d t o dr i v ing the bas e band in p u ts o f th e ad8349 . th e ad9777 is a d u al 16-b i t d a c t h a t can gen e r a te e i t h er a b a s e b a nd o u tp ut o r a co m p lex if usin g th e de vice s com p lex mo d u l a t o r . the basic in t e r f ace b e tween t h e ad9777 s i ou t output s a n d t h e ad8349 s dif f er en t i al bas e b a n d in p u ts is sh o w n in f i gur e 51. the resisto r s r 1 a nd r2 s e t t h e dc b i as le vel, and r3 s e t s t h e a m p l i t ud e o f t h e ba se ba n d in p u t v o l t a g e sw i n g. optional low-pass filter 03570-0-052 r1q r2q r3q 69 68 16 15 i outb2 i outa2 qbbn qbbp 73 72 1 2 i outb1 i outa1 ibbn ibbp ad9777 ad8349 optional low-pass filter r1i r2i r3i f i g u re 51. bas i c a d 97 77 to a d 8 3 4 9 i n t e r f ace 0.15 0.30 0.45 0.60 0.75 0.90 1.05 1.20 1.35 1.50 differential iq swing (v p-p) r3 ( ? ) 10 100 1.10 3 03570-0-053 f i g u re 52. r e l a t i on s h ip bet w ee n r 3 in f i g u re 51 and p e ak baseb a nd input v o ltag e . biasing and fil t ering a val u e o f 40 ? o n r1 and r2 in f i gur e 51 wil l g e n e r a t e t h e r e q u ir ed 400 mv dc b i as. n o t e tha t this is indep e nden t o f th e val u e o f r3. f i gur e 52 s h o w s t h e r e la t i o n shi p b e tw e e n t h e val u e o f r3 a nd t h e p e ak b a s e b a n d in p u t v o l t a g e wi t h t h e 40 ? r e sis t o r s in p l ac e . f r o m f i gur e 52, i t can b e s een tha t a val u e o f 240 ? wil l p r o v ide a p e ak-t o-p e ak s w in g o f a p p r o x ima t e l y 1.2 v p-p dif f er en t i al in t o the ad8349 s b a s e band in p u ts. the c l os es t a v a i la b l e r e sis t o r val u es a r e 40.2 ? a nd 240 ?, a nd th es e val u es w e r e us ed in the c h a r ac t e r i za tio n of th e ad8349 w h en t h e d a c was us e d as a sig n al s o ur ce . w h en usin g a d a c, lo w-p a s s i m a g e r e je c t f i l t e r s a r e typ i cal l y us e d t o e l i m ina t e ima g es t h a t a r e p r o d uce d b y t h e d a c. the y p r o v ide t h e add e d b e n e f i t o f e l i m ina t in g b r o a db a nd n o is e t h a t mi g h t fe e d i n to t h e mo d u l a tor f r om t h e d a c . f i gur e 53 s h o w s a sin g le sideband s p ec tr um a t 2140 mh z. the b a s e b a nd si n e and co sine sig n a l s co m e f r o m t h e dig i t a l ou tp u t of a r o hd e & s c h w ar z a m iq ar b i t r ar y w a ve for m ge ne r a tor . th es e sig n als dr i v e the ad9777 d u al d a c, which in t u r n dr i v es th e ad8349 s b a s e ban d in p u ts. n o t e tha t t h e ad9777 s com p lex mo d u l a tor i s no t b e i n g u s e d . d u e t o o f fs et v o l t a g es, i n t e r n al de vice misma t ch, a nd im p e r f e c t q u adr a t u r e o v er th e ad8349 s op era t in g ra n g e , th e ss b s p ec tr um has a n u m b er o f un desira b l e co m p on en ts s u ch as lo fe e d t h r o ug h and undesir e d sid e b a nd le a k a ge. w h en t h e ad8349 is dr i v en b y a m o d u l a ted bas e ban d sig n al , (e .g. 8-ps k, g m s k , q p s k , o r q a m ) , t h e s e n o n i d e a l i t i e s w i l l m a n i f e s t t h ems e l v es as deg r ade d er r o r v e c t o r ma g n i t ude (e vm), a nd deg r ade d sp e c t r a l p u r i ty . ?90 ?80 ?70 ?60 ?50 ?40 ?30 ?20 ?10 0 10 amp l itude (dbm) ssb = 1.7dbm lo = ? 44.5dbm usb = ? 52dbc third harmonic = ? 36.8dbc 03570-0-054 c e n t e r 2 . 1 4 g h z span 10mhz f i gur e 5 3 . ad83 49 si ngle si de ba nd spe c tr um a t 21 40 m h z reducing undesired sideban d l e ak a g e u n desir e d sideb a nd le a k a ge is t h e r e su l t o f pha s e an d am pl i t ud e im b a lan c es b e t w e e n t h e i and q cha nnel b a s e b a nd sig n a l s. ther efo r e , t o r e d u ce t h e u n desir e d sideb a n d le aka g e , t h e a m pli t ude an d phas e o f t h e b a s e b a nd sig n als ha v e t o b e ma t c h e d a t t h e mixer co r e s. b e ca us e o f misma t ch es i n t h e
ad8349 rev. 0 | page 19 of 28 ba se ba n d i n p u t pa th s lea d in g t o th e mi x e r s , pe rf ectl y m a t c h e d ba se ba n d si gn als a t t h e p i n s o f th e de v i ce m a y n o t be pe rf ectl y ma t c h e d w h e n t h e y r e ach t h e mixers. th er efo r e , s l ig h t ad j u s t m e n t s ha v e t o b e made to t h e phas e an d a m pli t udes o f t h e bas e band sig n als t o co m p e n s a t e fo r th es e misma t ch es. b e g i n b y ma k i ng o n e o f t h e i n pu ts, s a y t h e i ch a nnel, t h e r e fer e n c e sig n al . then ad j u s t t h e a m pli t ude and phas e o f t h e q c h a n n e l s sig n al un til t h e u n wan t e d sideb a n d p o w e r r e ac h e s a tr o u g h . the ad9777 has b u il t-in ga in ad j u s t r e g i s t ers tha t al lo w this t o be p e r f o r m e d easil y . i f a n i t era t i v e ad j u s t m e n t is p e r f o r m e d b e twe e n t h e am pli t u d e an d t h e ph as e, t h e u n desir e d sideb a nd le a k a ge can b e min i mi ze d sig n if ican t l y . n o te t h a t t h e com p e n s a te d si deb a nd r e j e c t ion p e r f o r ma n c e deg r ades as t h e o p er a t i n g b a s e b a nd f r e q uen c y i s m o ve d a w a y f r om t h e f r e q u e nc y a t w h i c h t h e c o m p e n s a t i on w a s p e r f or me d. a s a re su lt, t h e f r e q u e nc y of t h e i and q s i ne w a ve s shou l d b e a p p r o x im a t ely ha lf t h e b a s e b a nd b a n d wi d t h o f t h e m o d u l a te d ca r r i er . f o r exa m ple , if t h e m o d u l a t o r is b e in g us e d t o t r a n smi t a si n g le w c d m a ca rri e r wh ose ba se ba n d s p ect r um s p a n s f r o m dc t o 3.84/2 m h z, t h e cal i b r a t io n co u l d be ef f e c t i v e l y p e r f o r m e d wi t h 1 m h z i and q sine w a ves . reduc t ion of l o feed through b e ca us e t h e i and q sig n als a r e b e i n g m u l t i p lie d w i t h t h e l o , an y i n te r n a l of f s e t volt age s on t h e s e i n put s w i l l re su lt i n l e a k age o f t h e l o t o t h e o u t p ut. a d di t i onal l y , a n y i m b a l a n c e in t h e l o t o rf in t h e mixers wil l als o ca us e th e lo sig n al t o leak thr o ug h th e mi x e r t o th e r f o u t p u t . th e l o f eed th r o ug h i s c l ea r l y visib l e in t h e sin g le sideban d sp e c tr um. th e no minal l o fe e d t h r o ug h o f C42 dbm can b e r e d u ce d f u r t h e r b y a p ply i n g o f fs et co m p en s a t i o n v o l t a g es o n t h e i and q in pu ts. n o te t h a t t h e lo fe e d t h r o ug h is r e d u ce d b y va r y in g t h e dif f er en t i al o f fs et v o l t a g es o n t h e i a nd q in p u ts ( x b b p C xbb n ), n o t b y va r y in g th e n o minal b i as lev e l o f 400 mv . this is easil y acco m p lish e d b y pro g r a m m i ng a n d t h e n s t or i n g t h e a ppropr i a t e d a c of f s e t c o d e r e q u i r ed t o mi ni m i z e t h e l o f eed th r o ugh . th i s , h o w e v e r , r e q u ir es a dc-cou p l ed p a t h f r o m the d a c t o th e i and q in p u ts. the p r o c e d ur e fo r r e d u cin g t h e l o fe e d t h r o ug h is sim p le . a dif f er en t i al o f fs et v o l t a g e is a p plie d f r o m t h e i d a c un t i l t h e lo f eed th r o ugh r e ac h e s a tr o u g h . w i t h th i s o f fse t lev e l h e ld , a dif f er en t i al o f fs et v o l t a g e is a p plie d t o t h e q d a c un t i l a lo w e r t r o u g h is r e ach e d (this is a n i t e r a t i v e p r o c e s s). f i g u re 5 4 show s a pl ot of lo f e e d t h rou g h ve r s u s i ch an nel o f fs et (in mv) af t e r t h e q chann e l o f fs et has b e en n u l l e d . this s u g g es ts t h a t t h e co m p en s a t i n g o f fs et v o l t a g e sh o u ld ha v e a r e s o l u tio n o f a t leas t 100 v t o r e d u ce t h e l o feed thr o ug h t o b e les s tha n C65 db m. f i gur e 55 s h o w s the sin g le sideba nd s p ectr um a t 2140 mh z a f t e r th e n u lli n g o f th e l o . t h e r e d u ce d l o f eed th r o ug h ca n c l ea r l y be s e e n w h e n co m p a r ed w i t h th e p e r f or m a nc e s h ow n i n f i g u re 5 3 . c o m p en s a te d lo fe e d t h r o ug h deg r ades s o me w h a t as t h e l o fr e q u e n c y i s m o v e d a w a y fr o m th e fr e q u e n c y a t w h i c h th e co m p e n s a t i o n was p e r f o r m e d . this va r i a t ion is v e r y sma l l acr o ss a 30 mhz o r 60 mh z c e l l u l a r b a n d , h o w e ver . this sma l l va r i a t ion is d u e t o t h e ef fe c t s o f l o -t o- rf o u t p u t le aka g e arou nd t h e p a c k age a n d on t h e b o ard. ?7 0 ?6 0 ?5 8 ?5 6 ?5 4 ?5 2 carrie r fe e d through (dbm) ?6 2 ?6 8 ?6 6 ?6 4 3.0 4.0 4.5 5.0 5.5 3.5 iopp-iopn (mv) 03570-0-055 f i g u re 54. pl ot of l o f eedt h r o ug h v s . i chann e l bas e ban d o f f s et (q chann e l o f f s et null ed) ?90 ?80 ?70 ?60 ?50 ?40 ?30 ?20 ?10 0 10 amp l itude (dbm) c e n t e r 2 . 1 4 g h z span 10mhz 03570-0-077 ssb = 1.7dbm lo = ? 71.4dbm usb = ? 52dbc third harmonic = ? 36.8dbc f i gur e 5 5 . ad83 49 si ngle si de ba nd spe c tr um a t 21 40 m h z af t e r l o nul l i n g sideband s u ppression and l o feed throu g h versus temper a t ure i n p r ac t i ca l a p plica t ion s , r e d u c t io n o f lo fe e d t h r o ug h an d un desir e d sideb a nd su pp r e ssio n ca n b e p e r f o r m e d as a on e t i m e c a l i br a t i o n , w i t h t h e re qu i r e d c o r r e c t i on f a c t or s b e i n g store d i n n o n v ol a t i l e r a m. th es e co m p en s a t i on s c h e mes h o ld u p we l l o v er t e m p era t ure . f i gur e 40 a n d f i gur e 41 s h o w th e va r i a t ion in lo fe e d t h r o ug h a nd sideb a nd su p p r essio n o v er tem p er a t ur e af te r c o m p e n s a t i on i s p e r f or me d a t 2 5 c .
ad8349 rev. 0 | page 20 of 28 single sideband performance versus baseband drive level figure 56 shows the ssb output power and noise floor in dbc/100 khz versus baseband drive level at lo frequencies of 940 mhz, 1960 mhz, and 2140 mhz. improving third harmonic distortion while sideband suppression can be improved by adjusting the relative baseband amplitudes and phase, the only means available to reduce the third harmonic is to reduce the output power. (see figure 19, figure 20, and figure 21) it is worth noting, however, that as the output power is reduced, the noise floor, in dbc, stays fairly constant at the higher end of the power curve (figure 56). this indicates that the output power can be reduced to a level that yields an acceptable third harmonic without incurring a signal-to-noise ratio penalty. the constant snr versus output power relationship also indicates that baseband voltage variations can be effectively used to control system output power and/or regulate signal chain gain. ?14 ?10 ?6 ?8 ?12 ?2 ?4 4 2 6 0 ?104 ?90 ?86 ?88 ?84 ?102 ?100 ?98 ?96 ?94 ?92 0.2 0.3 0.4 0.5 0.8 0.6 0.9 1.0 1.2 1.1 0.7 03570-0-056 differential baseband drive (v p-p) ssb output power (dbm) 20 mhz noise floor (dbc/100khz) 940 ssb 1960 ssb 2140 ssb 1960 20 mhz noise 940 20 mhz noise 2140 20 mhz noise figure 56. ssb p out and 20 mhz noise floor vs. baseband drive level (f lo = 940 mhz, 1960 mhz, and 2140 mhz)
ad8349 rev. 0 | page 21 of 28 appli c a t ions 3gpp wcdm a single- c arrier applic a t ion the i n t e r p ol a t i o n f i l t er us e d for t h e m e as ur emen t o f w c d m a p e r f o r ma n c e is sh own i n f i gur e 57. this t h ir d or der b e ss e l f i l t e r has a 3 db ban d wid t h o f 12 mh z. w h ile t h e 3g p p sin g le c h a n n e l b a ndwid th is onl y 3.84 mh z, this wide 3 db ban d wid t h o f 12 mh z was dr i v en b y the n e ed f o r a f l a t g r ou p de l a y o u t t o a t lea s t h a lf th e ba n d w id th o f th e ba se ba n d si gnal . f i gur e 58 s h o w s a p l o t o f a w c d m a s p e c tr um a t 2140 mh z usin g t h e 3 gp p t e st m o de l 1 (64 c h a n ne ls ac ti v e ). a t an o u t p u t p o w e r o f C17.3 db m, an ad jacen t c h ann e l p o w e r ra tio (a cp r) j u s t sh y of C69 db c was m e as ur ed . f i gur e 59 s h o w s th e v a r i a t i o n in a c p r wi th o u t p u t po w e r a t 1960 mh z and 2140 mh z. i t al s o s h o w s t h e n o is e f l o o r me a s u r e d a t a n of f s e t of 3 0 m h z f r om t h e c e n t e r of t h e m o d u la t e d w c d m a s i gn al . f r o m th e gra p h s , i t c a n be seen tha t t h er e is an o p t i mal o u t p u t p o wer a t w h ich t o op era t e t h a t deli vers t h e b e st a c pr . i f t h e ou t p ut p o w e r is i n cr e a s e d b e yo nd tha t p o in t, th e a c p r deg r ades as th e r e s u l t o f incr eas e d d i s t o r ti o n . b e lo w th a t o p tim u m, th e a c p r de gra d e s d u e t o a r e d u c t io n i n t h e sig n a l -t o- n o is e ra t i o o f t h e sig n a l . 03570-0-058 680nh 680nh 100pf 40.2 ? 40.2 ? 240 ? 73 72 1 2 i outb1 i outa1 ibbn ibbp ad9777 ad8349 270pf 680nh 680nh 100pf 40.2 ? 40.2 ? 240 ? 69 68 16 15 i outb2 i outa2 qbbn qbbp 270pf f i g u re 57. sing l e - c arr i e r wc dm a a p p lic at i o n c i rcu i t (da c -m odul at or i n ter c onn e c t ) ?130 ?120 ?110 ?100 ?90 ?80 ?70 ?60 ?50 ?40 ?33 amplitude (dbm) c e n t e r 2 . 1 4 g h z span 24.6848mhz 03570-0-059 ch pwr = ? 17.3dbm adj cpr = ? 68.7db alt cpr = ? 72.7db alt lo adj lo ch adj up alt up f i g u re 58. sing l e - c arr i e r wc dm a spe c t r a l p l ot at 2 1 4 0 m h z, inc l uding a c pr an d a l te rnat e ch ann e l p o we r r a t i o ?7 2 ?7 0 ?6 8 ?6 9 ?7 1 ?6 6 ?6 7 ?6 4 ?6 5 ?6 3 ?6 2 ? 157 ? 151 ? 149 ? 150 ? 147 ? 148 ? 156 ? 154 ? 155 ? 152 ? 153 ?26 ? 24 ? 2 2 ? 20 ?18 ? 14 ? 1 6 ? 12 ?10 ? 8 03570-0-060 1960 acpr channel power (dbm) acp r (db) 3 0 mhz nois e floor (dbm/hz) 2140 acpr 1960 noise 2140 noise f i gure 59. sing l e - c arr i e r wc dma a c p r and no ise f l o o r (dbm/ h z) at 30 m h z carr ie r o ffs et v s . chann e l p o wer at 19 60 m h z and 2 1 4 0 mh z ( t est mo del 1 wi th 6 4 a c ti v e channel s ) wcdma mul t ic arrier applic a t io n the hig h d y namic ra n g e o f the ad8349 als o p e r m i t s us e in m u l t ic a r r i er w c d m a a p plic a t io n s . f i gur e 60 s h o w s a 4-ca r r ier w c d m a s p ec tr um a t 1960 m h z. a t a p e r - ca r r i er p o w e r o f C23 db m, a n a c p r of C60.7 db is achie v e d . f i gur e 61 sh o w s t h e var i a t ion in a c p a nd n o is e f l o o r (db c /h z) wi t h o u t p u t p o w e r .
ad8349 rev. 0 | page 22 of 28 ? 140 ? 120 ? 110 ? 100 ?90 ?80 ?70 ?60 ?50 ?40 amplitude (dbm) ch pwr = ? 23.2dbm adj cpr = ? 60.7dbm alt cpr = ? 62.3dbm ? 130 c e n t e r 1 . 9 6 g h z span 50mhz 03570-0-062 f i g u re 60. 4- ca rri er wcdm a spec t r al plot at 2 1 4 0 m h z, includ ing a c pr an d a l te rnat e ch ann e l p o we r r a t i o ?67 ?65 ?63 ?61 ?59 ?57 ?55 ?53 ?36 ?3 4 ? 3 2 ? 30 ?28 ? 26 ? 2 4 ? 22 ?20 ? 18 ? 1 6 channel power (dbm) alt and adj cpr (db) ?152 ?150 ?148 ?146 ?144 ?142 ?140 ?138 3 0 m hz noise floor (dbm/hz) 03570-0063 2140 adj cpr 2140 alt cpr 2140 noise 1960 alt cpr 1960 noise 1960 adj cpr f i gure 61. 4- ca rri er wcdma adjacent and a l tern ate ch a nnel p o wer rat i o and 30 m h z no ise f l o o r (db m / h z) v s . bb d r ive l e vel at 1 9 6 0 m h z and 21 40 m h z gsm/edge applic a t io n f i g u re 6 2 an d fi g u re 6 4 show p l ot s of g m sk e r ror ve c t or ma gni t ude (e vm), s p ec tral p e r f o r ma n c e , an d n o ise f l o o r (db c /100 kh z a t 6 mh z ca r r i er o f fs et) a t 885 mh z and 1960 mh z. b a s e d o n sp e c t r a l p e r f o r ma n c e, a max i m u m o u tpu t p o we r l e vel of arou nd 2 dbm i s a ppropr i a t e. n o te, how e ve r , t h a t as the o u t p u t p o w e r decr eas e s b e lo w this lev e l , t h er e is o n l y a v e r y slig h t i n cr e a s e i n t h e db c no is e f l o o r . this in d i c a t e s t h a t b a s e b a nd dr i v e va r i a t ion c a n b e us e d to co n t r o l o r co r r e c t t h e g a i n of t h e s i g n a l ch ai n ove r a r a nge of a t l e a s t 5 d b , w i t h l i tt l e or no sn r p e n a lt y . f i g u re 6 3 an d fi g u re 6 5 show p l ot s of 8 - p s k e v m , sp e c t r a l p e r f o r ma n c e , and n o is e f l o o r a t 885 mh z an d 1960 mh z. an lo dr i v e l e vel o f a p p r o x im a t ely C6 dbm is r e co m m e n de d fo r gms k an d 8-ps k. a hig h er l o dr i v e p o w e r wi l l i m p r o v e t h e n o is e f l o o r slig h t ly ; h o w e ver , i t a l s o tends to deg r ade evm. ? 110 ?90 ?80 ?85 ? 100 ?70 ?75 400khz and 600khz spectral mask (dbc/30khz) 6m h z offset n o ise floor ( d b c /100kh z) ?60 ?65 ?50 ?55 ?95 ? 105 1.0 1.5 2.0 2.5 3.0 3.5 4.0 evm % ?2 ?4 ?8 ?6 ?1 0 0 2 4 6 channel power (dbm) 03570-0065 peak noise floor 400khz 600khz average noise floor evm f i g u re 62.gm s k e v m , spec t r al p e r f or ma nce , a n d n o is e f l o o r vs. channe l p o w e r ( f r equ e nc y = 885 mhz) ?110 ?9 0 ?8 0 ?8 5 ?100 ?7 0 ?7 5 400khz and 600khz spectral mask (dbc/30khz) 6m h z offset n o ise floor ( d b c /100kh z) ?6 0 ?6 5 ?5 0 ?5 5 ?9 5 ?105 1.0 1.5 2.0 2.5 3.0 3.5 4.0 evm % ?6 ?8 ?1 2 ? 1 0 ?1 4 ? 4 ? 2 0 4 channel power (dbm) 2 03570-0066 peak noise floor 400khz 600khz average noise floor evm f i g u re 63. 8- psk e v m , spec t r al p e r f or ma nce , a n d n o is e f l o o r vs . cha nnel p o w e r (f r e que n c y = 88 5 mhz ) ?110 ?9 0 ?8 0 ?8 5 ?100 ?7 0 ?7 5 400khz and 600khz spectral mask (dbc/30khz) 6m h z offset n o ise floor ( d b c /100kh z) ?6 0 ?6 5 ?5 0 ?5 5 ?9 5 ?105 1.0 1.5 2.0 2.5 3.0 3.5 4.0 evm % ?5 ?7 ?1 1 ? 9 ?1 3 ? 3 ? 1 1 5 channel power (dbm) 3 03570-0067 peak noise floor 400khz 600khz average noise floor evm f i gure 64. gmsk e v m, sp ec tr al p e r f or mance , and n o ise f l oor vs . cha nnel p o w e r (f r e que n c y = 19 60 mhz )
ad8349 rev. 0 | page 23 of 28 ?110 ?90 ?80 ?85 ?100 ?70 ?75 400khz and 600khz spectral mask (dbc/30khz) 6mhz offset noise floor (dbc/100khz) ?60 ?65 ?50 ?55 ?95 ?105 1.0 1.5 2.0 2.5 3.0 3.5 4.0 evm% channel power (dbm) 03570-0068 peak noise floor 400khz 600khz average noise floor evm ?6 ?8 ?12 ?10 ?14 ?4 ?2 0 2 figure 65. 8-psk evm, spectral performance, and noise floor vs. channel power ( frequency = 1960 mhz) soldering information the ad8349 is available in a 16-lead tssop package with an exposed paddle. the exposed paddle must be soldered to the exposed metal of a ground plane for a lowered thermal impedance and reduced inductance to ground. this results in a junction-to-air thermal impedance ( ja ) of 30c/w. if multiple ground planes are present, the area under the exposed paddle should be stitched together with vias. lo generation using plls analog devices has a line of plls that can be used for generating the lo signal. table 4 lists the plls together with their maximum frequency and phase noise performance. table 4. adi pll selection table adi model frequency f in (mhz) at 1 khz phase noise dbc/hz, 200 khz pfd adf4111bru 1200 C78 adf4111bcp 1200 C78 adf4112bru 3000 C86 adf4112bcp 3000 C86 adf4117bru 1200 C87 adf4118bru 3000 C90 analog devices also offers the adf4360 fully integrated synthesizer and vco on a single chip that offers differential outputs for driving the local oscillator input of the ad8349. this means that the user can eliminate the use of the balun necessary for the single-ended-to-differential conversion. the adf4360 comes as a family of chips with six operating frequency ranges. one can be chosen depending on the local oscillator frequency required. the user should be aware that while the use of the integrated synthesizer might come at the expense of slightly degraded noise performance from the ad8349, it can be a much cheaper alternative to a separate pll and vco solution. table 5 shows the options available. table 5. adf4360 family operating frequencies adi model output frequency range (mhz) adf4360-1 2150/2450 adf4360-2 1800/2150 adf4360-3 1550/1950 adf4360-4 1400/1800 adf4360-5 1150/1400 adf4360-6 1000/1250 adf4360-7 lower frequencies set by external l transmit dac options the ad9777 recommended in the previous sections of this data sheet is by no means the only dac that can be used to drive the ad8349. there are other dacs that are appropriate, depending on the level of performance required. table 6 lists the dual tx- dacs that adi offers. table 6. adi dual tx C dac selection table part resolution (bits) update rate (msps min) ad9709 8 125 ad9761 10 40 ad9763 10 125 ad9765 12 125 ad9767 14 125 ad9773 12 160 ad9775 14 160 ad9777 16 160
ad8349 rev. 0 | page 24 of 28 ev alua tion board a p o p u l a t e d ad8349 eval ua tio n bo a r d is a v ai la b l e . the ad8349 has a n exp o s e d p a ddle u n der n e a t h the p a c k a g e , w h ich is s o lder e d t o t h e b o a r d . the e v a l u a t i on b o a r d is desig n e d wi t h ou t an y co m p on e n ts on t h e unde rside o f t h e bo a r d s o tha t h e a t ma y be a p p l ie d under the ad8349 f o r easy re mov a l a n d re p l a c e m e n t of t h e du t . 03570-0-074 yoping toh mike chowkwanyun f i g u re 66. layo ut o f ev aluat i on bo ar d, t o p l a yer 03570-0-073 f i g u re 67. ev aluat i on b o a r d s ilk s c r e e n table 7. e v aluation board con f iguration option s c o m p o n e n t f u n c t i o n default conditi o n tp1, tp4, tp3 power supply and grou nd vector pins. not applica b le sw1, enop, tp2 output enable: place in the a positi on to connect the enop pin to +v s via pull-u p resistor r10. place in the b p o sition to disab l e the device by grounding the pin enop through a 49.9 ? pull- down resistor . the device may be enabled via an external vo ltag e appli e d to the sma connector enop or t p 2. sw1 = a r1, r2, r5, r9, c8Cc11 baseb and input filters: these co mponents c a n b e used to implement a low-pass filter for the base band signa l s. r1, r2, r5, r9 = 0 ?, c8 C c11 = ope n
ad8349 rev. 0 | page 25 of 28 03570-0-072 c5 100pf c6 0.1 f qp qn c2 100pf c1 100pf lo r4 200 ? r3 200 ? r6 open t1 e t c- 1- 1 - 13 1 2 3 4 5 6 7 8 16 15 14 13 12 10 9 11 ibbp ibbn com1 com1 loin loip vps1 enop qbbp qbbn com3 com3 vps2 vout com3 com2 tp2 enop ip in r8 49.9 ? enop c7 100pf vout +v s +v s ad 8349 r2 0 ? b a r10 10k ? c9 open tp1 gnd c10 open r5 0 ? r11 0 ? tp3 vpos c8 open r1 0 ? r9 0 ? tp4 gnd c11 open c3 0.1 f c4 100pf r7 0 ? f i g u re 68. ev aluat i on b o a r d s c h e m a t i c
ad8349 rev. 0 | page 26 of 28 cha racteriza tion setups ssb se tup the p r ima r y s e t u p us ed t o c h a r ac t e r i ze t h e ad8349 is s h o w n in f i gur e 69. this s e t u p was us ed t o eval ua t e t h e p r o d uc t as a sin g le-sideb and m o d u l a t o r . t h e in t e r f ace b o a r d has cir c ui t r y th a t co n v e r t s t h e si n g le - e n d ed i a n d q i n p u t s f r o m th e a r b i tra r y f u n c tion g e n e ra t o r t o dif f er en tial in p u ts wi t h a dc b i as o f 400 mv . a d di tional l y , th e in t e r f ace bo a r d p r o v ides co nnec t io n s f o r p o w e r s u p p l y r o u t in g. th e hp34970a and i t s as s o c i a t ed p l ug-in 34901 wer e us ed t o m o ni t o r p o w e r s u p p l y c u rr en ts an d v o l t a g es bein g su p p lied t o th e ad8349 c h a r ac t e r i za tion bo a r d . t w o hp34907 pl ug-in s w e r e us e d t o p r o v ide addi tio n al mis c e l l a n e o u s dc a nd co n t r o l sig n als t o th e in t e r f ace bo a r d . the l o in p u t was dr i v en dir e c t l y b y a n rf sig n al gen e r a t o r an d t h e ou t p ut was me a s u r e d dire c t ly w i t h a sp e c t r u m ana l y z e r . w i t h t h e i chan n e l dr i v en b y a si n e w a ve and t h e q cha n n e l b y a cosin e wa v e , t h e lo w e r sideba n d is th e sin g le sideba nd (ss b ) output . t h e t y pi c a l s s b output s p e c t r u m i s s h ow n i n fi g u re 5 3 . ieee hp34970a d1 d2 d3 34901 34907 34907 d1 d2 d3 interf a c e bo ard i_in q_in output_1 output_2 arb function gen ieee tekafg2020 vps1 vn gnd vp +15v max com +25v max ?25v max hp3631 ieee ad8349 characterization board p1 in ip qp qn enop v out p1 in ip qp qn rfout ieee agilent e4437b lo ieee pc controller spectr um anal yzer rf i/p ieee hp8561e 03570-0-076 f i g u re 69. a d 8 3 4 9 char ac t e ri zat i on b o a r d ssb t e s t s e t u p
ad8349 rev. 0 | page 27 of 28 outline dimensions compliant to jedec standards mo-153-abt 16 9 8 1 exposed pad (pins down) 5.10 5.00 4.90 4.50 4.40 4.30 6.40 bsc 3.00 sq top view bottom view 1.20 max 0.15 0.00 0.30 0.19 seating plane 8 0 1.05 1.00 0.80 0.20 0.09 0.75 0.60 0.45 0.65 bsc figure 70. 16-lead thin shrink small outline with exposed pad [tssop/ep] (re-16-2) dimensions shown in millimeters ordering guide model temperature range (c) package description package option ad8349are C40 to +85 tube, 16-lead tssop re-16 AD8349ARE-REEL7 C40 to +85 7" tape and reel re-16 ad8349-eval evaluation board
ad8349 rev. 0 | page 28 of 28 notes ? 2003 analog devices, inc. all rights reserved. trademarks and registered trademarks are the prop erty of their respective owners. c03570-0-11/03(0)

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