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1.5 ghz to 2.4 ghz rf vector modulator ad8341 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 . 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 . fea t ures cartesian ampl itude and phas e modulation 1.5 gh z to 2.4 ghz fr equ e ncy range co ntinuo us ma gnitude c o ntro l o f ?4.5 db to ?34.5 db continuous phase control of 0 to 360 output third-o r der intercept 17.5 dbm output 1 db co mpression poi n t 8.5 dbm output noise fl oor ?150.5 db m/hz @ full gai n adjustable mo dulatio n band width up to 23 0 mhz fast output power disable 4.75 v to 5.25 v single-s u pply voltage applic ati o ns rf pa lin eariza t ion/rf predistortion amplitud e and phase modula tion variable atten u ators and pha s e shifters cdma20 00, w c dma, gsm/edge lin ear power amplifiers smart antenna s func tio n a l block di agram 90 0 vps2 qbbm qbbp rfip rfim dsop ibbm ibbp rfop rfom 04700-001 vprf cmop fi g u r e 1 . general description the ad8341 v e c t o r m o d u l a t o r p e r f o r m s a r b i tra r y a m p l i t ude a nd phas e m o d u la t i on o f a n r f sig n al . sin c e t h e rf sig n al p a t h is lin e a r , t h e o r ig ina l mo d u la t i on is p r es er v e d . this p a r t can b e us e d as a genera l-p u r p os e rf mo d u l a t o r , a va r i ab le a t t e n u - a t o r /p has e shif ter , o r a r e m o d u l a t o r . th e am p l i t ude can b e co n t r o l l ed f r o m a maxim u m o f ?4.5 db t o les s tha n ?34.5 db , a nd t h e p h as e c a n be s h if t e d con t in uo us l y o v er th e en tir e 360 ra n g e . f o r maxim u m ga in, t h e ad8341 de l i v e rs a n o p 1db o f 8.5 db m, an o i p3 o f 17.5 db m, a nd an o u t p u t n o is e f l o o r o f ?150.5 db m/h z , in dep e n d en t of p h as e . i t o p era t es o v er a f r eq uen c y ra n g e o f 1.5 gh z t o 2 . 4 gh z. the b a s e b a n d i n p u ts in c a r t esi a n i and q fo r m a t con t r o l t h e am pl it u d e and phas e mo d u l a t i on im p o s e d on t h e rf i n p u t sig n al . b o th i and q in p u ts a r e dc-co u p l ed wi th a 500 mv dif f er en t i a l f u l l - s ca le ra n g e. the max i m u m m o d u la t i on b a nd - wid t h is 230 m h z, w h ic h can b e r e d u ce d b y addin g ext e r n al ca p a c i t o rs t o li mi t t h e n o is e b a n d wi d t h o n t h e co n t r o l lin e s . b o t h t h e rf in pu ts an d o u t p u t s ca n b e us e d dif f er en t i al l y o r sin g le-e n d e d and m u st b e ac-cou ple d . t h e rf i n p u t and o u t p ut im p e dan c es a r e n o minal l y 50 ? o v er t h e o p era t in g f r e q uen c y ra n g e . th e dsop p i n al lo ws t h e o u t p u t s t a g e t o b e dis a b l e d qu i c k l y i n ord e r to prote c t sub s e q u e n t st age s f r om ove r d r ive. the ad8341 o p era t es o f f s u p p ly v o l t a g es f r o m 4.75 v t o 5.25 v while co ns uming a p p r o x ima t e l y 125 ma. the ad8341 is fa b r ica t e d o n analog devices p r o p r i eta r y , hig h p e r f o r ma n c e 25 gh z so i com p lem e n t a r y b i p o l a r i c p r o c es s. i t is a v a i la b l e i n a 24-le ad , pb -f r e e lfcs p p a cka g e a nd o p er a t es o v er a ?40c t o +85c t e m p era t ur e ra n g e . e v al u a tio n bo a r ds are a v ai l a bl e .
ad8341 rev. 0 | page 2 of 20 table of contents specifications ..................................................................................... 3 absolute maximum ratings ............................................................ 4 esd caution .................................................................................. 4 pin configuration and function descriptions ............................. 5 typical performance characteristics ............................................. 6 theory of operation ...................................................................... 10 rf quadrature generator ......................................................... 10 i-q attenuators and baseband amplifiers .............................. 11 output amplifier ........................................................................ 11 noise and distortion .................................................................. 11 gain and phase accuracy .......................................................... 11 rf frequency range .................................................................. 11 applications ..................................................................................... 12 using the ad8341 ...................................................................... 12 rf input and matching ............................................................. 12 rf output and matching .......................................................... 13 driving the i-q baseband controls ......................................... 13 interfacing to high speed dacs .............................................. 14 cdma2000 application ............................................................ 14 wcdma application ................................................................ 15 evaluation board ............................................................................ 17 outline dimensions ....................................................................... 20 ordering guide .......................................................................... 20 revision history 7/04revision 0: initial version
ad8341 rev. 0 | page 3 of 20 specifications v s = 5 v, t a = 25c, z o = 50 ?, f = 1.9 ghz, single-ended, ac-coupled source drive to rfip through 1.2 nh series inductor, rfim ac-coupled through 1.2 nh series inductor to common, differen tial-to-single-ended conversion at output using 1:1 balun. table 1. parameter conditions min typ max unit overall function frequency range 1.5 2.4 ghz maximum gain maximum gain setpoint for all phase setpoints ?4.5 db minimum gain v bbi = v bbq = 0 v differential (at recommended common-mode level) ?34.5 db gain control range relative to maximum gain 30 db phase control range over 30 db control range 360 degrees gain flatness over any 60 mhz bandwidth 0.5 db group delay flatness over any 60 mhz bandwidth 50 ps rf input stage rfim, rfip (pins 21 and 22) input return loss from rfip to cmrf (with 1.2 nh series inductors) 12 db cartesian control interface (i and q) ibbp, ibbm, qbbp, qbbm (pins 16, 15, 3, 4) gain scaling 2 1/v modulation bandwidth 500 mv p-p, sinusoidal baseband input single-ended 230 mhz second harmonic distortion 500 mv p-p, 1 mhz, sinusoidal baseband input differential 41 dbc third harmonic distortion 500 mv p-p, 1 mhz, sinusoidal baseband input differential 47 dbc step response for gain setpoint from 0.1 to 0.9 (v bbp = 0.5 v, v bbm = 0.55 v to 0.95 v) 45 ns for gain setpoint from 0.9 to 0.1 (v bbp = 0.5 v, v bbm = 0.95 v to 0.55 v) 45 ns recommended common-mode level 0.5 v rf output stage rfop, rfom (pins 9, 10) output return loss measured through balun 7.5 db f = 1.9 ghz gain maximum gain setpoint ?4.5 db output noise floor maximum gain set point, no input ?150.5 dbm/hz p in = 0 dbm, frequency offset = 20 mhz ?149 dbm/hz output ip3 f1 = 1900 mhz, f2 = 1897.5 mhz, maximum gain setpoint 17.5 dbm adjacent channel power cdma2000, single carrier, p out = -4 dbm, maximum gain, phase setpoint = 45 (see figure 35) ?76 dbm output 1 db compression point maximum gain 8.5 dbm power supply vps2 (pins 5, 6, and 14), vprf (pins 19 and 24), rfop, rfom (pins 9 and 10) positive supply voltage 4.75 5 5.25 v total supply current includes load current 105 125 145 ma output disable dsop (pin 13) disable threshold (see figure 24) v s /2 v attenuation dsop = 5 v 33 db enable response time delay following high-to-low transition until rf output amplitude is within 10% of final value. 30 ns disable response time delay following low-to-high transition until device produces full attenuation 15 ns
ad8341 rev. 0 | page 4 of 2 0 absolute maximum ra tings table 2. p a r a m e t e r s r a t i n g supply voltage vprf, vps 2 5.5 v dsop 5.5 v ibbp, ibbm, qbb p , qbbm 2.5 v rfop, rfom 5.5v rf input power at maximum gain 13 dbm, re: 50 ? (rfip or rfi m , si ngle-ended drive) equivalent volta g e 2.8 v p-p internal power dissipation 825 mw ja (with pad so l d ered to board) 59 c/ w maximum junction temperature 125c operating temperature range ?40c to +85c storage temperature range ?65c to +150c lead temperature range (soldering 60 sec) 300c s t r e s s es a b o v e t h os e lis t e d u n de r a b s o l u t e m a xi m u m r a t i n g s ma y c a us e p e r m a n en t dama ge t o t h e de vice . this is a s t r e s s ra t i n g onl y ; f u n c t i o n al o p era t ion o f t h e de vice a t t h es e o r an 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 c a ution esd (electrostatic discharge) sensitive device. ele c trosta tic charg e s as high as 4000 v readily accumulate on the human body and test eq uipment and can discharge without detection. although this product features proprie - tary esd protect i on circuitry, permanent damag e may o ccur on devices subje c ted to high energy electrostatic discharges. ther efore, prop er esd precautions a r e reco mmende d to avoid performance degradation or lo ss of functionality.
ad8341 rev. 0 | page 5 of 2 0 pin conf igura t ion and fu nction descriptions 18 17 16 15 1 2 3 24 vpr f cmrf rfip rfim cmrf vpr f 14 13 dsop vps2 ibbm ibbp iflm iflp 7 8 9 10 11 cmop cmop rfom rfop cmop cmop 12 4 5 6 vps2 vps2 qbbm qbbp qflm qflp 23 22 21 20 19 ad8341 top view (not to scale) pin 1 indicator 04700-002 f i g u re 2. 24-l e ad l e ad f r a m e ch ip s c al e p a ck ag e (lfcs p ) ta ble 3. pi n f u nct i on d e s c ri pt i o ns pin o. neonic function 1, 2 qflp, qflm q base b and inp ut filter pins. connect option a l c a pacitor to reduce q base band channe l lo w-pa s s corner frequenc y. 3, 4 qbbp, qb bm q channe l differential ba seba n d inputs. 5, 6, 14, 19, 24 vps2, vp rf positive supply voltage. 4.75 v ? 5.25 v. 7, 8, 11, 12, 20, 2 3 cmop, cmrf device common. connect via lowest po ssi ble i m pedance to external circuit co mmon. 9, 10 rfop, rfom differential rf outputs. m u st be ac-coupled. differential impeda n ce 50 ? nomin al. 13 dsop output disable. pull hi gh to disable output stage. 15, 16 ibbm, ibbp i channel differ e ntial ba seba nd inputs. 17, 18 iflm, iflp i baseba n d input filter pins. con n ect optiona l ca pa citor to red u ce i baseba nd channel low- pas s corner frequenc y. 21, 22 rfim, rfi p differential rf inputs. must be ac-coupled. differential impeda n ce 50 ? nomin al.
ad8341 rev. 0 | page 6 of 2 0 typical perf orm ance cha r acte ristics 04700-003 gain setpoint 0 0.3 0.5 0.9 1.0 0.8 0.7 0.6 0.4 0.2 0.1 gain ( d b) 0 ?5 ?4 0 ?1 0 ?1 5 ?2 0 ?2 5 ?3 0 ?3 5 phase setpoint = 180 phase setpoint = 270 phase setpoint = 90 phase setpoint = 0 f i g u re 3. g a in m a g n it ude v s . g a in s e t p oint at d i f f e r e nt p h ase s e tpo i nts, r f f r eq uenc y = 19 00 mh z 04700-004 gain setpoint 6 gain conformance e rror (db) ?8 ?7 ?6 ?5 ?4 ?3 ?2 ?1 0 1 2 3 4 5 0 0.1 1.0 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 phase setpoint = 180 phase setpoint = 270 phase setpoint = 225 phase setpoint = 0 phase setpoint = 90 phase setpoint = 45 phase setpoint = 135 phase setpoint = 315 f i gure 4. g a in conf or ma nc e e r ror v s . g a in s e tpoi nt at d i f f e r e nt p h as e s e t p oint s, r f f r equ e n c y = 1 9 00 m h z 04700-005 phase setpoint (degrees) ?2 45 gain ( d b) ?2 8 ?2 6 ?2 4 ?2 2 ?2 0 ?1 8 ?1 6 ?1 4 ?1 2 ?1 0 ?8 ?6 ?4 315 270 360 180 90 135 225 0 gain setpoint = 0.1 gain setpoint = 0.5 gain setpoint = 0.25 gain setpoint = 1.0 f i g u re 5. g a in m a g n it ude v s . p h as e s e t p oint at d i f f e r e nt g a in s e tpoi nts, rf f r equ e nc y = 1 9 0 0 mh z 04700-006 1.0 gain conformance e rror (db) ? 4.5 ? 4.0 ? 3.5 ? 3.0 ? 2.5 ? 2.0 ? 1.5 ? 1.0 ? 0.5 0 0.5 phase setpoint (degrees) 45 315 270 360 180 90 135 225 0 gain setpoint = 0.1 gain setpoint = 0.25 gain setpoint = 0.5 gain setpoint = 1.0 f i g u re 6. g a in conf or ma nc e e r ror v s . phas e s e t p o i nt at d i ffer e nt g a in s e tpoints, r f f r equ e nc y = 19 00 m h z 04700-007 phase setpoint (degrees) 360 315 270 225 180 135 90 45 ph a se ( d egrees) 0 0 360 315 270 225 180 135 90 45 gain setpoint = 1.0 gain setpoint = 0.1 gain setpoint = 0.25 gain setpoint = 0.5 f i g u re 7. p h as e v s . p h as e s e t p o i nt at d i ffer e nt g a in s e tpoints, r f f r equ e nc y = 19 00 m h z 04700-008 phase setpoint (degrees) 0 4 5 9 0 135 360 180 225 270 315 ph a se er r o r ( d egrees) 25 ?1 5 ?1 0 ?5 0 5 10 15 20 gain setpoint = 0.1 gain setpoint = 0.5 gain setpoint = 1.0 gain setpoint = 0.25 f i g u re 8. p h as e e r ror v s . p h as e s e t p o i nt at d i f f e r e nt g a in s e t p oint s, r f f r equ e nc y = 1 9 00 m h z
ad8341 rev. 0 | page 7 of 2 0 04700-009 gain setpoint 0 1.0 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 noi s e (dbm/ h z) ? 147 ? 154 ? 153 ? 152 ? 151 ? 150 ? 149 ? 148 no rf input rf pin = ? 5dbm rf pin = 0dbm rf pin = +5dbm f i g u re 9. o u t p ut n o is e f l o o r v s . g a i n s e t p o i nt , n o is e i n d b m/ h z , no ca rr ie r , and w i th 19 0 0 mh z ca rri er (m easu r e d at 2 0 m h z o ffset) p i n = ? 5 , 0, and +5 dbm 04700-010 frequency (mhz) 0 gain ( d b) ?2 8 ?2 6 ?2 4 ?2 2 ?2 0 ?1 8 ?1 6 ?1 4 ?1 2 ?1 0 ?8 ?6 ?4 ?2 1500 1600 1700 1800 1900 2000 2100 2200 2300 2400 gain setpoint = 1.0 gain setpoint = 0.5 gain setpoint = 0.25 gain setpoint = 0.1 f i gure 10. g a in vs. f r equ e nc y at d i ffe rent g a in s e tp oints, ph a s e s e t p o i n t = 0 04700-011 frequency (mhz) 1500 2400 2300 2200 2100 2000 1900 1800 1700 1600 nois e (dbm/hz) ? 146 ? 154 ? 153 ? 152 ? 151 ? 150 ? 149 ? 148 ? 147 f i gure 11. o u tput nois e f l oo r v s . f r eq uenc y , maxi mum g a in, no r f carr ie r , p h as e s e t p oi nt = 0 04700-012 frequency (mhz) 1500 2400 2300 2200 2100 2000 1900 1800 1700 1600 gain ( d b) 0 ?1 ?2 ?3 ?4 ?5 ?6 ?7 ?8 ?9 ?10 ?4 0 c +25 c +85 c f i gure 1 2 . g a i n m a gni t ude vs . f r equenc y a n d t e m p er a t u r e , ma xim u m g a i n , p h a s e s e tp oi nt = 0 04700-013 100 1000 900 800 700 600 500 400 300 200 rf outp ut am s i de band p o we r (dbm) 0 ?10 ?20 ?30 ?40 ?50 ?60 ?70 ?80 ?90 ? 100 differential bb level (mv p-p) fundamental power, 1899mhz, 1900mhz second baseband harmonic product, 1898mhz, 1902mhz third baseband harmonic product, 1897mhz, 1903mhz f i g u re 13. bas e b a n d ha r m on ic d i s t o r t i on (i a n d q ch ann e l , rf input = 0 db m, o u tput balun and c a bl e l o sses o f ap p r o x i m a t e l y 2 db not a c count e d for in plot) 04700-014 frequency (mhz) 1500 2400 2300 2200 2100 2000 1900 1800 1700 1600 op 1 d b (dbm) 12 0 2 4 6 8 10 ?40 c +25 c +85 c f i gure 1 4 . o u tput 1 db c o m p r e ssio n p o i n t vs . f r equenc y a n d t e m p er at ure , m a x i m u m g a in , p h as e s e t p oi nt = 0
ad8341 rev. 0 | page 8 of 2 0 04700-015 frequency (mhz) 1500 2400 2300 2200 2100 2000 1900 1800 1700 1600 oip3 ( d bm) 25 0 5 10 15 20 ?4 0 c +25 c +85 c f i g u re 15. o u t p ut ip3 v s . f r equ e nc y a n d t e mpe r at u r e , m a x i m u m g a in , p h as e s e t p o i nt = 0 , 2 . 5 m h z carr ie r sp a c ing 04700-016 frequency (mhz) 10 410 360 310 260 210 160 110 60 rf outp ut am s i de band p o we r (dbm) ?10 ?35 ?30 ?25 ?20 ?15 1v p-p bb input 500mv p-p bb input 250mv p-p bb input f i gure 16. i/q m o d u lat i on bandwidth vs. baseband m a g n itude 04700-017 0 360 45 90 135 180 225 270 315 op 1 d b (dbm) 10 ?15 ?10 ?5 0 5 phase setpoint (degrees) gain setpoint = 1.0 gain setpoint = 0.5 gain setpoint = 0.25 gain setpoint = 0.1 f i gure 1 7 . o u tput 1 db c o m p r e ssio n p o i n t vs . g a i n a n d p h ase s e tpo i nts, r f f r eq uenc y = 19 00 mh z 04700-018 0 360 45 90 135 180 225 270 315 oip3 (dbm) 20 ?10 ?5 0 5 10 15 phase setpoint (degrees) gain setpoint = 1.0 gain setpoint = 0.5 gain setpoint = 0.25 gain setpoint = 0.1 f i g u re 18. o u t p ut ip3 v s . g a in and ph as e s e t p o i nt s, r f f r equ e nc y = 1 9 00 m h z, 2. 5 m h z carr ie r sp ac ing 04700-019 frequency (mhz) outp ut p o we r (dbm) 0 ?1 0 ?2 0 ?3 0 ?4 0 ?5 0 ?6 0 ?7 0 ?8 0 ?9 0 ?100 center 1.9ghz 500khz/ span 5mhz 1sa rbw 30khz vbw 30khz swt 100ms rf att 20db unit dbm ref lvl 0dbm a de s i re d s i de band rf fe e d through unde s i re d s i de band s e c ond bas e band harmonic s e c ond bas e band harmonic f i g u re 19. sing l e -si d eband p e r f or man c e , r f f r equenc y = 19 00 m h z , r f input = ?1 0 db m; 1 m h z, 50 0 mv p -p d i f f e rent i a l bb d r ive 04700-020 0 180 30 330 60 90 270 300 120 240 150 210 s11 rf port with 1.2nh inductors s11 rf port without inductors 1500mhz 2400mhz f i gure 20. input i m p e dance s m ith ch ar t
ad8341 rev. 0 | page 9 of 2 0 04700-021 0 180 30 330 60 90 270 300 120 240 150 210 sdd22 port differential s22 with 1 to 1 transformer 1500mhz 2400mhz f i gure 2 1 . o u tput im p e d a nce sm i t h c h ar t 04700-022 gain setpoint 0 1.0 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 ph a se er r o r ( d egrees) 0 ?10 ?20 ?30 ?40 ?50 ?60 ?70 phase setpoint = 0 phase setpoint = 45 phase setpoint = 90 f i g u re 22. phas e e r r o r v s . g a i n s e t p o i nt by p h as e s e t p oi nt , r f f r equ e nc y = 1 9 00 m h z 04700-023 temperature ( c) ? 4 0 ? 3 0 ? 2 0 ? 1 0 0 1 0 2 03 04 05 06 07 08 0 s u p p l y curre nt (ma) 127 126 125 124 123 122 121 v pos = 5.25v v pos = 4.75v v pos = 5.00v f i gure 23. sup p l y current v s . t e mper at ur e 04700-024 0 5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 rf outp ut p o we r (dbm) 0 ?55 ?50 ?45 ?40 ?35 ?30 ?25 ?20 ?15 ?10 ?5 dsop voltage (v) f i gure 2 4 . o u tput di sa ble a ttenu a t ion, rf f r equ e nc y = 1 9 00 m h z, rf input = ?5 d b m 04700-025 ch3 2.0v ? ch4 100mv ? m10.0ns 5.0gs/s a ch3 1.84v 3 4 time (10ns/div) volts dsop 2v/div 100mv/div rf output f i gur e 2 5 . o u tput di sa ble respo n se ti me , rf f r equ e nc y = 1 9 00 m h z, rf input = 0 db m
ad8341 rev. 0 | page 10 of 20 theor y of opera tion the ad8341 is a lin e a r rf v e c t o r m o d u la t o r wi th c a r t esian b a s e b a nd co n t rols. i n t h e si m p l i f i e d b l o c k d i a g r a m g i ve n in f i gur e 26, th e rf sig n al p r o p a g a t es f r o m t h e lef t t o th e r i g h t w h i l e b a s e b a nd co n t r o ls a r e place d ab o v e an d b e lo w . the rf in p u t is f i rst spli t in t o i n -ph a s e ( i ) a nd q u a d ra t u r e (q) co m p o - n e n t s. th e va r i ab le a t t e n u a t o r s i n de p e n d e n t l y s c ale t h e i an d q co m p on e n ts o f t h e rf i n p u t. th e a t t e n u a t o r ou t p uts a r e t h en s u mm ed a n d b u f f e r ed t o th e o u t p u t . b y co n t r o l l in g th e r e la t i v e am oun t s o f i an d q co m p on en ts tha t a r e s u mm e d , co n t in uo us ma g n i t ude and p h as e co n t r o l o f th e ga in is p o ss i b le . c o n s ider t h e v e c t o r ga in r e p r es en t a t i o n o f t h e ad8341 exp r ess e d in p o l a r f o rm in f i gur e 27. the a t t e n u a t ion fac t o r s fo r t h e i a nd q sig n al com p on e n ts a r e r e p r es en t e d on th e x- a n d y- a x is, r e s p ecti v e l y , b y th e ba se b a n d in p u t s , v bbi an d v bb q . th e r e s u l t a n t o f t h eir v e c t o r s u m r e p r es en ts t h e ve c t o r ga in, w h ich c a n a l s o b e ex p r ess e d as a ma g n i t ud e a nd pha s e. by a p pl yi n g dif f er en t com b ina t io ns o f b a s e b a n d i n p u ts, an y v e c t o r ga in wi t h in t h e uni t cir c le c a n b e p r og ra mm e d . a c h a n g e in sig n o f v bbi or v bb q ca n b e vi e w e d as a cha n ge i n sig n o f th e ga in o r as a 180 p h as e c h a n g e . th e o u t e r m os t cir c le r e p r es en ts t h e maxi m u m ga in ma g n i t ude o f uni t y . th e cir c le o r ig in im plies, in t h e o r y , a ga in o f 0. i n prac t i ce , cir c ui t m i s m at c h e s a n d u n av o i d a b l e s i g n a l f e e d t h r o u g h l i m i t t h e mini m u m gain t o a p p r o x ima t e l y ?34.5 db . the phas e a n g l e b e t w e e n th e r e s u l t a n t g a i n v e ct o r a n d th e po s i ti v e x - a x i s i s d e - f i n e d as t h e phas e s h if t. n o te t h a t t h er e is a n o minal , sys t ema t i c in s e r t io n p h as e thr o ug h th e ad8341 t o whic h t h e p h as e shif t is adde d . i n t h e fol l o w in g dis c us sio n s, th e syst ema t ic in s e r t io n phas e is n o r m a l ize d t o 0. the co r r esp o nd en c e b e tw e e n t h e desir e d ga i n and phas e s e t- po i n t s , ga i n sp and pha s e sp , and t h e c a r t esi a n i n p u ts, v bbi a nd v bb q , is g i v e n b y sim p le t r igo n om et r i c ide n t i t i e s () () [] 2 2 / / o bbq o bbi sp v v v v gain + = ( ) bbi bbq sp v v phase / arctan = w h er e: v o is th e bas e band s c alin g co ns t a n t (500 mv). v bbi and v bb q a r e t h e dif f er en t i a l i a nd q b a s e b a nd v o l t a g es, r e s p ecti v e l y . n o t e tha t w h e n ev al ua t i n g t h e a r cta n g e n t fun c tio n , th e p r o p e r phas e quadran t m u s t b e s e le c t e d . f o r exa m ple , if t h e p r i n ci p a l val u e o f th e a r c t a n g e n t (kn o wn as the ar c t a n g e n t (x)) is used , q u adran t s 2 and 3 co u l d b e i n te r p r e te d mist a k e n ly as q u a d ra n t s 4 a n d 1, r e s p ecti v e l y . i n g e n e ral , bo th v bbi and v bb q are ne e d e d in con c er t t o mo d u l a t e t h e gain a nd t h e phas e . pur e a m pli t ude m o d u l a t i on is r e p r es en te d b y radi al m o v e m e n t of t h e g a i n ve c t or t i p a t a f i x e d ang l e, w h i l e pu re ph a s e mo d u l a - t i on i s re pre s e n t e d by rot a t i o n o f t h e t i p arou n d t h e c i rcl e a t a f i xed radi us. u n lik e tradi t ional i - q m o d u l a t o rs, th e ad8341 is desig n e d t o ha ve a lin e a r rf sig n al p a th f r o m in p u t t o o u t p u t . t r ad i t io na l i-q m o d u l a t o rs p r o v ide a limi t e d lo ca r r i er p a t h t h r o u g h w h ich a n y am pli t ude i n fo r m a t io n is r e m o v e d . 04700- 026 linear attenuator linear attenuator v-i v-i 0 /90 i-v vbbq q channel input single-ended or differential 50 ? input z v bbi i channel input output disable single-ended or differential 50 ? output f i gure 26. si mpl i fi e d a r ch itec tu r e of th e a d 8 3 4 1 04700-027 |a| a +0.5 ?0.5 +0.5 ?0.5 v i v q min gain max gain f i gure 27. v e c t or g a in r e presentat i on rf qu adr a ture gener a t o r the rf i n p u t is dir e c t ly co u p le d dif f er en t i al ly o r sin g le-e n d e d t o t h e quadr a t u r e gen e r a t o r , w h ich co n s ist s o f a m u l t ist a ge r c p o lyphas e n e two r k t u n e d o v er t h e op era t i n g f r e q uen c y ra n g e o f 1.5 gh z t o 2.4 gh z. the r e c y c l in g na t u r e o f the p o l y p h as e n et- w o rk g e n e ra t e s tw o r e plicas o f t h e i n p u t sig n al, w h ich a r e in p r e c is e q u adra t u r e , i . e . , 90, t o e a ch o t h e r . sin c e t h e p a s s i v e n e tw o r k is p e r f e c t l y lin e a r , t h e am pli t ude and phas e info r m a t ion co n t a i ne d i n t h e rf in p u t is t r an smi t te d fai t hf u l ly to b o t h cha n - n e ls. the q u adr a t u r e o u t p uts a r e t h e n s e p a ra t e l y b u f f er e d t o dr i v e t h e r e s p e c t i v e a t ten u a t o rs. the cha r ac t e r i st ic im p e dan c e o f t h e p o lyphas e n e tw o r k is us e d t o s et t h e i n p u t im p e dan c e o f th e ad8341.
ad8341 rev. 0 | page 11 of 20 i - q at t e n u at o r s a n d b a seband amplifiers the p r o p r i e t a r y li ne ar -resp o ndi n g a t ten u a t o r st r u c t ur e is an a c ti v e s o l u ti o n w i th d i ff e r e n ti a l i n p u t s a n d o u t p u t s t h a t o f f e r e x c e llen t lin e a r i t y , l o w n o is e , a n d gr ea t e r imm u n i t y f r o m mi s- m a tch e s t h an o t her va r i ab l e a tte n u a t o r met h o d s. t h e g a in , i n l i n e ar t e r ms , of t h e i a n d q ch an n e l s i s pr op or t i o n a l to it s c o n t ro l v o lt age w i t h a s c a l i n g f a c t o r des i g n e d to b e 2/ v , i.e., a f u l l - s c a l e ga in s e t p o i n t o f 1.0 ( ? 4. 5 db) f o r a v bbi (o r a v bb q ) o f 5 00 mv . the co n t r o l v o l t a g e s ca n be d r i v en d i f f e r en t i all y o r sin g le -en d e d . th e com b in a t ion o f t h e b a s e b a nd am plif iers and a t ten u a t o rs a l lows fo r m a x i m u m mo d u l a t i on b a ndw i d t h s i n ex cess o f 20 0 m h z. outpu t am plifier the o u t p u t am plif ier accep t s t h e s u m o f t h e a t ten u a t o r o u t p u t s a nd de li v e rs a dif f er en t i al o u t p ut sig n al in t o t h e ext e r n al lo ad . the o u t p u t p i n s m u s t be p u l l ed u p t o a n ext e r n al s u p p l y , p r efera b ly t h r o ug h rf ch ok es. w h en t h e 50 ? lo ad is t a k e n dif f er en t i a l ly , an o u t p u t p1db and ip3 o f 8.5 dbm an d 17.5 dbm i s a c h i ev ed , r e s p ecti v e l y , a t 1. 9 gh z . th e o u t p u t ca n be tak e n i n sin g le-en d e d fashio n, albei t a t lo w e r p e r f o r ma n c e lev e ls. noise a n d dist or tio n the o u t p u t n o is e f l o o r a n d dis t o r t i o n le v e ls va r y wi t h t h e ga in ma g n i t ude b u t do n o t v a r y signif ican t l y wi t h t h e phas e . a t t h e hig h er ga in mag n i t ude s e t p o i n t s, t h e o i p3 and t h e n o is e f l o o r va r y in dir e c t p r o p o r tio n wi th t h e ga in. a t lo w e r ga in ma g n i - t u de s e t p oin t s, t h e n o is e f l o o r le v e ls o f f w h i l e t h e o i p3 co n t in ues t o va r y wi t h the ga in. gain and phase a c cu r a cy ther e a r e n u m e r o u s wa ys t o exp r es s t h e acc u rac y o f t h e ad8341. i d eal l y , th e ga in an d phas e sh o u ld p r e c is e l y f o l l o w th e s e tp o i n t s . f i g u re 4 i l lu st r a te s t h e g a i n e r ror i n d b f rom a b e st f i t li n e , n o rm aliz e d t o th e g a in m e as ur ed a t th e g a in set p o i n t = 1. 0, fo r t h e dif f er en t phas e s e t p oin t s . f i gur e 6 s h o w s t h e ga i n er r o r in a dif f er en t for m , n o r m alize d t o t h e ga i n m e as ur e d a t phas e s e t p oin t = 0; the p h as e s e t p o i n t is sw ep t f r o m 0 t o 360 f o r d i f f e r e n t g a i n s e tp oi n t s . f i g u re 8 an d f i g u re 2 2 s h ow an a l o g ou s er r o r s fo r t h e phas e er r o r as a f u n c t i on o f ga in a nd phas e s e tp o i n t s . t h e a c c u r a c y cl e a r l y d e p e nd s o n t h e re g i on of op e r a - t i on w i t h i n t h e ve c t or g a i n u n it c i rcl e . o p e r a t i o n ve r y cl o s e to t h e or i g i n g e n e r a l l y re su lt s i n l a r g e r e r ror s a s t h e rel a t i ve acc u r a c y o f t h e i a nd q ve c t o r s deg r ades. rf freque nc y r a nge the f r e q uen c y r a n g e o n t h e rf in p u t is limi t e d b y t h e i n t e r n al p o lyphas e quadra t u r e phas e- s p li t t e r . the phas e- s p li t t e r s p li ts t h e i n comin g r f in p u t i n t o tw o sig n als, 90 o u t o f phas e , as p r evio us l y d e scr i be d in th e rf quad ra t u r e gen e ra t o r sectio n . this p o lyphas e n e tw o r k has b e en desig n e d t o e n s u r e r o b u s t qu a d r a tu re a c c u r a c y ove r st and a rd f a br i c a t i o n pro c e s s p a ra m eter va r i a t io n s fo r t h e 1.5 gh z t o 2.4 gh z s p e c if ie d rf f r eq uen c y ra n g e. u s in g t h e ad8 341 as a sin g le-sideban d m o d u - la to r and m e a s ur in g t h e r e su l t i n g sideb a nd sup p r e ssio n is a g ood g a ug e o f h o w w e ll th e q u ad ra t u r e a c cura c y i s m a i n ta in ed ove r r f f r e q u e nc y . a t y pi c a l pl o t of s i d e b a n d suppre s s i on f rom 1.1 gh z t o 2.7 gh z is sh o w n in f i gur e 28. the lev e l o f sideband s u p p r es sio n deg r ada t io n o u tside t h e 1.5 gh z to 2.4 gh z sp e c i - f i e d ra n g e wi l l b e s u b j e c t t o man u fac t ur in g p r o c es s va r i a t io n s . 04700-028 ?15 ?20 ?45 ?40 ?35 ?30 ?25 0.7 2.7 2.5 2.3 2.1 1.9 1.7 1.5 1.3 0.9 1.1 frequency (ghz) sideband suppression (dbc) f i gure 28. sid e ban d sup p ression vs. f r equ e nc y
ad8341 rev. 0 | page 12 of 20 appli c a t ions using the ad8341 the ad8341 is desig n e d t o o p era t e in a 50 ? im p e dance sys t em. f i gur e 3 0 i l l u s t ra t e s an e x a m ple w h er e t h e rf i n p u t is dr i v en i n a sing le-e n d e d fashio n w h i l e t h e dif f er en t i al rf o u t - p u t is co n v er t e d t o a sin g le-ended o u t p u t wi th a n rf bal u n. the b a s e b a nd co n t rols fo r t h e i a n d q cha nnels a r e ty p i ca l l y dr i v e n f r o m dif f er en t i a l d a c o u t p u t s. the p o w e r s u p p lies, vp rf a nd vps2, s h o u l d b e b y p a s s e d a p p r o p r i a t e l y wi th 0. 1 f a n d 100 pf c a pa ci t o r s . lo w i n d u cta n c e gr o u n d i n g o f th e cm o p a n d c m rf co mm o n pin s is es s e n t ial t o p r e v en t uni n ten t i onal p e aki n g o f t h e ga in. rf input and ma t c hing the in p u t im p e dan c e o f th e ad8341 is def i n e d b y th e c h a r ac - t e r i s t ics o f t h e p o lyphas e netw ork. th e c a p a ci t i v e co m p onen t of t h e n e tw o r k ca u s es i t s i m p e dance t o r o l l -o f f wi t h f r e q uen c y a l b e i t a t a r a te sl owe r t h an 6 db / o c t a v e. by u s i n g ma tch i ng i n d u c t or s on t h e ord e r of 1 . 2 n h i n s e r i e s w i t h e a ch of t h e r f in p u ts, rfip and rfim, a 50 ? ma tch is achi e v e d wi t h a r e t u r n los s o f >10 db o v er t h e o p er a t i n g f r e q uen c y ra n g e . dif f er en t m a tch i ng i n d u c t or s c a n i m prove m a tc h i ng ove r a n a r rowe r f r e q uen c y ra n g e. th e si n g le-e nde d and dif f er en t i al i n p u t im p e dan c es a r e exac t l y t h e s a me . 04700-029 50 ? 100pf rf rfim rfip rc phase 1.2nh 100pf 1.2nh ~1vdc f i g u re 29. r f input inter f ac e to t h e a d 83 41 sh o w i n g c o upling capacitors and m a tching in duc t ors t h e r f i p a n d r f i m shou l d b e a c - c oupl e d t h ro u g h l o w l o ss s e r i es ca p a ci t o rs as sh o w n in f i gur e 29. th e i n ter nal dc le v e ls a r e at ap p r ox i m at e l y 1 v . fo r s i n g l e - e n d e d o p e r at i o n , o n e i n p u t is dr i v en b y t h e rf sig n al w h i l e t h e o t h e r i n p u t is ac g r o u n d e d . 04700-030 ibbp ibbm vps2 dsop qbbp qbbm vps2 vps2 vprf cmrf rfim rfip cmop cmop rfom rfop q f l p qflm cmop cmop cmrf vprf iflp iflm ad8341 c12 (see text) c11 (see text) c8 0.1 f l3 1.2nh c6 100pf l4 1.2nh c5 100pf ibbm ibbp vp rf input vp qbbp qbbm l1 120nh l2 120nh c14 0.1 f c10 0.1 f vp c18 100pf c17 100pf etc1-1-13 rf output a b output disable vp vp c1 0.1 f c3 0.1 f c2 100pf c7 100pf c4 100pf c9 100pf f i gure 30. bas i c connec t ions
ad8341 rev. 0 | page 13 of 20 rf output and ma t c hing the rf o u t p u t s o f th e ad8341, rfo p , a n d rfo m , a r e o p en col l e c to rs o f a t r a n sim p e d an ce am plif ier w h ich n e e d to b e p u lled u p t o th e pos i ti v e s u p p l y , p r e f e r a b l y w i th r f c h ok e s a s sho w n i n f i g u re 3 1 . t h e no m i n a l output i m p e d a nc e l o o k i n g in t o each in di vid u al o u t p u t p i n is 25 ?. c o n s eq uen t l y , th e dif f er en t i al ou t p u t im p e dan c e is 50 ?. 04700-031 50 ? differential 100pf 1:1 rf output rfom rfop r t r t 120nh 100pf v p g m i sig f i g u re 31. r f o u t p ut inter f ac e to t h e a d 83 41 sh o w i n g coupl i ng capa cit o rs, p u ll-u p r f ch okes, and b a lun sin c e t h e o u t p ut dc le v e ls a r e a t t h e p o si t i v e s u pply , ac co u p lin g ca p a c i t o rs wil l us ual l y be n e e d ed betw een the ad8341 o u t p u t s a nd t h e n e xt s t ag e in t h e syst em. a 1:1 rf b r o a db a nd o u t p ut b a lun, such as t h e et c1-1-13 (m/a -co m ), co n v er ts t h e dif f er en tia l o u t p u t o f th e ad8341 in to a si n g le-e nde d sig n a l . n o te t h a t t h e lo ss and b a l a nce o f t h e bal u n di r e ctl y i m pa ct th e a p pa r e n t o u t p u t po w e r , n o i s e f l oo r , a nd ga in/p has e er r o r s o f th e ad8341. i n cr i t ic al a p p l ic a t ion s , na r r o w -b a nd b a l u n s w i t h lo w lo ss an d su p e r i o r b a lan c e a r e r e co mme n d e d . i f t h e o u t p u t is t a k e n i n a sin g le -ende d fash io n dir e c t ly in to a 50 ? lo ad t h r o ug h a co u p li n g c a p a ci to r , t h er e wi l l b e an i m p e d - a n ce m i s m a t c h . t h i s ca n be r e s o l v ed wi th a 1: 2 bal u n t o co n v er t th e sin g l e -en d e d 25 ? o u t p u t im p e dance t o 50 ?. i f los s o f sig n a l sw in g is n o t cr i t i c a l , a 25 ? b a ck t e r m in a t io n i n s e r i es w i th th e o u t p u t p i n ca n a l s o b e u s e d . t h e un u s ed o u t p u t p i n m u s t s t ill be p u lled u p t o th e pos i ti v e s u p p l y . th e use r m a y loa d i t t h r o u g h a co uplin g c a p a ci to r wi t h a d u m m y l o ad to p r es er v e b a lan c e . the ga i n o f t h e ad834 1 w h en t h e o u t p u t is sin g le- en de d va r i es s l igh t ly wi t h d u mm y load val u e a s s h o w n in f i gur e 32. 04700-032 frequency (ghz) ? 2.5 ? 3.0 ? 3.5 ? 4.0 ? 4.5 ? 5.0 ? 5.5 ? 6.0 ? 6.5 ? 7.0 ? 7.5 ? 8.0 ? 8.5 gain ( d b) 3.0 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.8 r l2 = open r l2 = 50 ? r l2 = short r l = 50 ? f i gure 32. g a in of the ad8341 us ing a sing le -ended o u tput with d i fferent du mm y l o a d s , r l2 , on th e un used o u tput the rf o u t p u t s i g n al can b e dis a b l ed b y ra isin g th e dso p p i n t o t h e p o si t i v e su p p ly . the o u t p u t dis a b l e f u n c t i o n p r o v ides > 30 d b a t t e n u a t i o n o f th e i n p u t s i gn al ev en a t full g a i n . th e in ter f ace to ds op is hig h i m p e dan c e an d t h e sh u t down and t u r n -on r e s p o n s e t i m e s a r e <10 0 n s . i f t h e dis a b l e f u n c t i on is n o t n e ed e d , th e d s o p p i n s h o u ld be t i ed t o gr o u n d . drivi n g th e i- q baseband c o ntrols the i an d q i n pu ts t o t h e a d 83 41 s et t h e ga in and phas e b e - tw e e n i n p u t and o u t p u t . th e s e in p u ts a r e dif f er en t i al an d sh o u ld nor m a l ly ha ve a c o mmon- m o d e l e vel of 0 . 5 v . h o we ve r , w h e n dif f er en tial l y dr i v en, t h e co mmo n m o de can var y f r o m 250 mv t o 750 mv w h il e s t il l al lo win g f u l l ga in co n t r o l . e a c h in p u t p a ir has a n o mi nal i n p u t s w in g o f 0.5 v dif f er en t i a l a r o u n d t h e co mm o n -mo d e lev e l . th e maxim u m ga in o f uni t y is ac hiev e d if th e dif f er en tia l v o l t a g e is e q ual t o +500 mv o r ?500 mv . s o wi t h a comm o n -mo d e l e v e l o f 5 00 mv , ibb p and ib bm wil l eac h s w in g b e tw een 250 mv and 750 mv . the i an d q i n pu ts can a l s o b e dr i v en wi t h a si n g le-e n d e d sig n al . i n this c a s e , o n e side o f eac h in p u t sh o u l d b e tie d t o a lo w n o is e 0.5 v v o l t a g e s o ur ce ( a 0.1 f deco u p lin g c a p a ci t o r lo ca t e d clos e t o th e p i n is r e co m m e n d e d ), w h i l e th e o t h e r in p u t swin gs f r o m 0 v t o 1 v . di f f er en t i al d r i v e g e n e ral l y o f fe rs s u p e r i o r ev e n - o r d e r d i s t o r ti o n a n d l o w e r n o i s e th a n s i n g le - e n d ed d r i v e . the bandwid t h o f th e bas e b a n d co n t r o ls exceeds 200 mh z ev en a t f u l l -s cale bas e ba nd dr i v e . this al lo ws f o r v e r y fas t ga in an d phas e m o d u l a t i o n o f t h e rf i n p u t sig n al. i n cas e s w h er e lo w e r m o d u l a tio n band wid t hs a r e acc e p t a b le o r desir e d , ext e r n al f i l t er ca p a c i t o r s can b e co nn ec t e d acr o s s p i n s iflp t o iflm a nd q f lp t o q f lm t o r e d u ce t h e in g r es s o f bas e b a nd n o is e and s p ur io us sig n al in t o t h e con t r o l p a th.
ad8341 rev. 0 | page 14 of 20 the 3 db b a n d wi d t h is s e t b y ch o o sin g c fl t a c c ord i n g to t h e f o ll o w i n g eq ua tio n : pf 0.5 nf 10 khz 45 f 3db + flt c this eq ua tio n ha s been v e r i f i ed f o r val u e s o f c fl t f r o m 10 pf t o 0.1 f (ba n d w id th s e t t in g s o f a p p r o x i m a t e l y 4.5 k h z t o 4 3 mh z). interf a c ing t o high s p eed d a cs 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 i a nd q v e c t o r con t r o ls o f th e ad8341. w h ile t h es e in p u ts c a n in g e n e ral b e dr i v en b y a n y d a c, t h e dif f er en t i al ou t p u t s an d b i as lev e l o f the ad i txd a c? fa mil y al lo ws f o r a dir e c t co nn ec tion bet w een d a c a n d m o d u la t o r . the ad977x famil y o f d u al d a cs has dif f er en t i al c u r r en t o u t - p u ts. th e f u l l -s c a le c u r r en t is us er p r og ra mma b l e a nd is us ual l y s et t o 20 ma, tha t is, eac h o u t p u t swin gs f r o m 0 ma t o 20 ma. the basic in t e r f ace b etween t h e ad9777 d a c o u t p u t s an d t h e ad8341 i an d q in p u ts is sh o w n in f i gur e 33. the resist o r s r1 a nd r2 s e t t h e dc b i as le ve l accor d in g t o t h e e q u a t i o n : bi a s l e v e l = a v e r a g e o u tp u t c u r r en t r1 f o r exa m ple , if th e f u l l -s cale c u r r en t f r o m e a ch o u t p u t is 20 ma , e a ch o u t p u t wi l l ha v e an a v era g e c u r r en t o f 10 ma. th er efo r e to s et t h e b i as le v e l t o t h e r e co mmen de d 0.5 v , r1 a nd r2 sh o u ld b e s e t t o 50 ? e a ch. r1 an d r2 sh o u ld a l wa ys b e e q ua l. i f r3 is o m i t t e d , this wil l r e s u l t in a n a v ailab l e s w in g f r o m t h e d a c o f 2 v p-p dif f er en t i al, which is t w ice t h e maxim u m v o l t a g e ra n g e r e q u ir ed b y the ad8341. d a c r e s o l u tio n ca n be max i mi ze d b y a ddin g r3, w h ich s c a l es down t h is vol t a g e acco r d in g t o t h e fol l o w in g e q u a t i o n : = swing scale full () () ? ? ? ? ? ? + ? + r3 r2 r2 r3 r2 r1 i max 1 || 2 optional low-pass filter 04700-033 r1 r2 r3 i outb2 i outa2 qbbm qbbp i outb1 i outa1 ibbm ibbp ad9777 ad8341 optional low-pass filter r1 r2 r3 f i g u re 33. bas i c a d 97 77 to a d 8 3 4 1 i n t e r f ace 04700-034 ( ? ) 130 50 55 60 65 70 75 80 85 90 100 105 115 120 110 125 95 diffe r e n tial p e ak-to-p e ak s w ing (v ) 1.15 1.08 1.10 1.13 1.00 1.02 1.05 0.95 0.97 0.88 0.90 0.92 0.77 0.80 0.82 0.85 0.70 0.75 0.72 fi g u r e 3 4 . pe a k - t o - pe a k d a c o u t p u t s w i n g v s . s w i n g s c al ing resist o r r 3 (r1 = r2 = 50 ) f i gur e 34 s h o w s t h e r e la t i on s h i p b e tw e e n t h e value o f r3 a nd t h e p e a k b a s e b a nd vol t a g e w i t h r1 a nd r2 e q ua l to 50 ?. f r o m f i gur e 34, i t can be s e en t h a t a val u e o f 100 ? f o r r3 wil l p r o v ide a p e ak- t o-p e a k s w in g of 1 v p-p dif f er en t i al in t o t h e ad8341 s i an d q in p u ts. 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 te t h e n y q u is t i m a g es p r o d uce d b y t h e d a c. the y als o p r o v i d e t h e adde d b e n e f i t o f e l imina t in g b r o a d b and n o is e t h a t mig h t fe e d i n t o t h e m o d u l a t o r f r o m t h e d a c. cdma2000 applic a t ion t o t e st the co m p lian ce t o th e cd ma2000 bas e s t a t ion s t anda r d , a sin g le-ca r r i er cd ma2000 t e st m o de l sig n al ( f o r wa r d p i lo t, sy nc, p a g i ng, a nd six t r a f f i c as p e r 3gpp2 c.s00 10-b , t a b l e 6.5.2.1) was a p plied t o t h e ad8 341 a t 1960 mh z. a c a vi ty t u n e d f i l t er was us e d to r e d u ce n o i s e f r o m t h e sig n al s o ur ce b e i n g a p plie d t o t h e de v i ce . th e 6.8 mh z p a s s b a nd o f t h is f i l t er is a p p a re n t in t h e subs e q u e n t sp e c t r a l pl ot s . f i g u re 3 5 show s a pl ot of t h e s p e c t r u m of t h e o u tput s i g n a l un der n o m i na l co ndi t i on s. p ou t is eq ual t o ?4 db m an d v bbi = v bb q = 0.353 v , i . e . , v ibbp ? v ibbm = v qb bp ? v qbbm = 0.353 v . n o is e and di st or t i o n is m e asur e d in a 1 mh z b a n d wi d t h a t 2.25 mh z c a r r ier o f fs et (30 kh z m e as ur em en t bandwid t h ).
ad8341 rev. 0 | page 15 of 20 1rm 1avg a span 10mhz 1mhz/ center 1.96hz ?20 ?12 ?40 ?50 ?60 ?70 ?80 ?90 ? 100 ?112 marker 1 [t1 ] ?18.47dbm 1.95999900ghz 1 rbw 30khz vbw 100khz swt 500ms rf att 0db unit dbm ref lvl ?12dbm 04700-035 ?30 0.3db offset 1 [t1] ?18.47dbm 1.95999900ghz ch pwr ? 4.06dbm acp up ?77.64dbm acp low ?76.66dbm c11 c11 c0 c0 cu1 cu1 f i g u re 35. o u t p ut s p ec t r u m , 19 60 m h z, si ng l e - c arr i e r cd m a 20 00 t e st mode l at ? 4 d b m, v bb i = v bb q = 0. 35 3 v , adja c e nt ch anne l p o we r mea s ured a t 2 .25 mhz ca rri e r o ffset i n 1 mh z b w input si gnal f i lt er ed u s ing a cav i t y t u n e d f i lte r ( p as s b a nd = 6.8 m h z) h o ldin g t h e dif f er en t i a l i an d q co n t r o l v o l t a g e s s t e a d y a t 0.353 v , in p u t p o w e r was sw ep t. f i gur e 36 s h o w s va r i a t ion in s p ur io us co n t en t, a g a i n m e as ur e d a t 2.25 m h z ca r r i er o f fs et in a 1 mh z b a n d w i d t h, as def i n e d b y t h e 3gpp2 sp e c if ic a t io n . 04700-036 ?7 0 ?9 0 ?8 8 ?8 6 ?8 4 ?8 2 ?8 0 ?7 8 ?7 6 ?7 4 ?7 2 acp @ 2 . 2 5 m hz offs e t (dbm, 1 m hz, bw) ?20 ? 18 ?16 ? 14 ? 1 2 ? 10 ?8 ? 6 ?4 ?2 0 output power (dbm) f i g u r e 36. ad j a ce n t c h an n e l p o we r v s . o u t p u t p o we r , cdma2 000 si ngle c a r r i e r @ 1 960 mh z ; a c p me a s ur e d a t 2. 2 5 mh z carr ie r o ffset (1 mh z bw ); v bbi = v bb q = 0 . 35 3 v w i t h a f i xed in p u t p o w e r o f 2.4 db m, t h e o u t p u t p o w e r was a g a i n sw ep t b y exer cisin g t h e i a nd q in p u ts. v bbi a nd v bb q we re k e p t eq u a l an d w e r e sw ep t f r om 100 mv t o 500 mv . th e r e s u l t - in g o u t p u t p o w e r a nd a c p a r e sh own i n f i gur e 37. 04700-037 0 ?30 ?25 ?20 ?15 ?10 ?5 outp ut p o we r (dbm) 0 0.1 0.2 0.3 0.4 0.5 iq control voltage ?60 ?65 ?70 ?75 ?80 ?85 ?90 a c p db m ( 1 m h z b w ) @ 2.25m h z offset f i g u re 37. o u t p ut p o we r and a c p v s . i and q cont r o l v o lt ag es, cdm a 20 00 t e s t m o de l , v bb i = v bb q , a c p m e as ured at 2. 2 5 m h z ca rr ier o f f s et in 1 m h z bw f i gu r e 37 s h o w s t h a t fo r a f i xe d in p u t po w e r , t h e a c p (m e a s u r e d in db m ) trac ks th e o u t p u t po w e r as th e ga in i s c h a n g e d . wcdma applic a t ion f i gur e 38 s h o w s a p l o t o f th e o u t p u t s p ec tr um of th e ad8341 t r a n smi t t i ng a s i n g le-c a r r i er w c d m a sig n al ( t est m o de l 1 - 64 a t 2140 m h z). the ca r r i er p o w e r is a p p r o x ima t e l y ?9 db m. the dif f er en tial i and q co n t r o l v o l t a g es a r e bo th e q ual t o 0.353 v , t h a t is, t h e v e c t or is si t t in g on t h e uni t cir c le a t 4 5 . a t t h is p o w e r le v e l, a n ad jace n t chan n e l p o w e r ra t i o o f ?61 db c is a c h i ev ed . th e al t e rn a t e c h a n n e l po w e r ra ti o o f ? 72 d b c i s do mina t e d b y th e n o is e f l o o r o f th e ad8341. 1rm span 25mhz 2.5mhz/ center 2.14ghz ?30 ?24 ?50 ?60 ?70 ?80 ?90 ? 100 ?110 ? 120 ? 124 offset 1db 04700-038 ?40 a marker 1 [t1 ] ? 28.39dbm 2.14050000ghz rbw 30khz vbw 300khz swt 1s rf att 0db unit dbm ref lvl ?24dbm 1 [t1] ? 28.39dbm 2.14050000ghz ch pwr ?8.95dbm acp up ?60.78db acp low ?60.82db alt1 up ?72.67db alt1 low ?72.66db 1 c12 c12 c11 c11 c0 c0 cu1 cu1 cu2 f i g u re 38. a d 8 3 4 1 sing l e - c ar ri er wc dm a spec t r u m at 21 40 m h z f i gur e 39 sh o w s h o w a c pr and n o is e v a r y wi t h va r y in g in p u t p o w e r (dif f e r e n t ial i and q co n t r o l v o l t a g es a r e h e l d a t 0.353 v). a t hig h p o w e r le vels, b o t h a d ja cen t and a l ter na te cha n nel p o w e r ra t i os in cr e a s e sha r ply . a s o u tpu t p o w e r dr o p s, ad jace n t and al t e rn a t e c h a n n e l po w e r ra ti os bo th r e a c h m i n i m u m s be f o r e th e m e as ur e m en t b e co m e s do mina t e d b y t h e n o is e f l o o r o f t h e ad8341. a t this p o in t, ad jac en t a nd al ter na t e c h a nne l p o w e r r a t i o s b e c o m e approx i m atel y e q u a l .
ad8341 rev. 0 | page 16 of 20 a s t h e o u t p u t p o w e r dr o p s, t h e n o is e f l o o r , m e as ur e d i n dbm in 1 mh z b w a t 50 mh z ca r r i er o f fs et, dr o p s s l ig h t l y . 04700-039 ?30 ?80 ?75 ?70 ?65 ?60 ?55 ?50 ?45 ?40 ?35 adj ace nt/alte rnate channe l p o we r ratio (dbc ) ? 3 0 ? 25 ?20 ? 15 ?10 ? 5 0 5 output power (dbm) ?5 0 ?5 5 ?6 0 ?6 5 ?7 0 ?7 5 ?8 0 ?8 5 ?9 0 ?9 5 ? 100 nois e dbm @ 5 0 m hz carrie r offs e t (1 mhz bw) acpr 5mhz offset acpr 10mhz offset noise ?50mhz offset f i gur e 3 9 . ad83 41 a c p r a n d noi s e vs . output p o w e r ; sing l e - c ar ri er wc dm a ( t es t m o de l 1 - 64 at 21 40 m h z) f i g u re 4 0 show s how output p o we r , a c pr , a n d noi s e v a r y w i t h t h e dif f er en t i a l i a nd q co n t r o l v o l t a g es. v bbi a nd v bb q are t i e d t o g e th er an d a r e va r i ed f r o m 0. 5 v t o 50 mv . 04700-040 0 ?50 ?45 ?40 ?35 ?30 ?25 ?20 ?15 ?10 ?5 outp ut p o we r (dbm) 0 0.1 0.2 0.3 0.4 0.5 iq control voltage ?40 ?45 ?50 ?55 ?60 ?65 ?70 ?75 ?80 ?85 ?90 acp r (dbc ) n o ise db m @ 50m h z offset ( 1 m h z b w ) output power dbm acpr 10mhz offset noise ?50mhz offset acpr 5mhz offset f i gur e 4 0 . ad83 41 output p o w e r , a c pr a n d no i s e vs . v iq . sing l e - c ar ri er wc dm a ( t es t m o de l 1 - 64 at 21 40 m h z) i n th i s ca se , ad ja ce n t c h a n n e l p o w e r ra ti o r e m a i n s co n s ta n t a s t h e ( n o i s e domi na te d) a l ter n a t e cha n n e l p o w e r deg r ades r o ug hl y 1-f o r - 1 wi t h o u t p u t p o w e r . a s t h e i and q co n t r o l v o l t - a g e dr o p s, t h e no is e f l o o r a g a i n dr o p s slo w ly .
ad8341 rev. 0 | page 17 of 20 ev alua tion board the e v al u a tion bo a r d cir c ui t s c h e ma tic f o r th e ad8341 is s h own in f i gur e 41. the e v a l u a t i on b o a r d is co nf ig ur e d to b e dr ive n f r o m a sin g le-en d e d 50 ? s o ur ce . al th oug h the in p u t o f th e ad8341 is dif f er en t i a l , i t ma y b e dr i v en si ng le-e n d e d , wi t h n o los s o f p e r - fo r m anc e . the lo w-p a s s cor n er f r e q uen c y o f t h e b a s e b a n d i a nd q cha n - n e ls ca n b e r e d u ce d b y in st a l ling ca p a c i to rs in t h e c11 an d c12 p o si t i o n s. th e l o w-p a s s co r n er f r e q uen c y fo r ei t h er cha n ne l is a pprox i m a t e d by pf 0.5 nf 10 khz 45 f 3db + flt c o n th i s ev al ua tio n boa r d , th e i a n d q ba se b a n d ci r c u i t s a r e iden t i ca l t o e a ch o t h e r , s o t h e fol l o w in g des c r i p t io n a p plies e q ua l l y to e a ch. the co n n e c t i ons a nd cir c ui t conf igur a t io n fo r t h e q b a s e b a nd in p u ts a r e des c r i b e d in t a b l e 4. the bas e b a n d in p u t o f t h e ad8341 r e q u ir es a dif f er en tial v o l t - a g e dr i v e . the e v al ua t i o n b o a r d is s et u p t o al lo w s u ch a dr i v e b y co nne c t in g t h e dif f er en t i al v o lt a g e s o ur ce t o qb b p and qb b m . the co mm on- m o d e v o l t a g e sho u ld b e ma i n t a i n e d a t a p p r o x i- ma te ly 0.5 v . f o r t h is co nf igura t io n, j u m p ers w1 t h r o ug h w4 shou l d b e re mo ve d. the b a s e b a n d i n p u t o f t h e e v alua t i on b o a r d ma y als o b e dr i v e n wi t h a si n g le-e nde d vol t a g e. i n t h is cas e , a b i as lev e l is p r o v ide d to t h e u n u s e d i n pu t f r om p o te n t i o me te r r 1 0 by i n st a l l i ng e i t h e r w1 o r w2 . s e t t in g s w 1 in p o si tio n b dis a bles th e ad8341 o u t p u t a m p l if ier . w i t h s w 1 s et to p o si t i o n a, t h e o u t p u t am plif i e r is ena b le d . w i t h s w 1 s et to p o si t i o n a, an ext e r n al v o l t a g e sig n al, s u ch as a pu l s e, c a n b e a ppl i e d to t h e d s op sm a c o n n e c tor to e x e r c i s e t h e o u t p ut a m pl if ier ena b le/dis ab le f u n c t i on. table 4. e v aluation board con f iguration option s coponents function default conditi o ns r7, r9, r11, r14, r15, r19, r20, r21, c15, c19, w3, w4 i channel baseband interface . resistors r7 an d r9 may be installed to accom m od ate a base band sourc e that requires a specific termina t ing impedance. capacitors c15 and c19 are bypas s cap a citors. for single- e nde d baseband driv e, the potentiome ter r11 can be used to provide a bias level to the unused in put (insta ll either w3 or w4). r7, r9 = not installed r11 = potentiometer, 2 k?, 10 turn (bourns) r14 = 4 k? (size 0603) r15 = 44 k? (siz e 0603) r19, r20, r21 = 0 ? (size 0603) c15, c19 = 0.1 f (size 0603) w3 = jumper ( i nstalled ) w4 = jumper (open) r1, r3, r10, r12, r13, r16, r17, r18, c16, c20, w1, w2 q channel bas e band interfac e . see the i channel ba seb a nd interface section . r1, r3 = not installed r10 = potentiometer, 2 k?, 10 turn (bourns) r12 = 4 k? (size 0603) r13 = 44 k? (siz e 0603) r16, r17, r18 = 0 ? (size 0603) c16, c20 = 0.1 f (size 0603) w1 = jumper ( i nstalled ) w2 = jumper (open) c11, c12 baseband low-pass filter ing . by adding capacitor c11 between qflp and qflm, and c12 between iflp and iflm, the 3 d b low-pass corn er freq uency of the baseband interface can be reduced from 230 mhz (no minal). see equ a tion in text. c11, c12 = not i n stalled t1, c17, c18, l1, l2 output interfa c e . the 1:1 balun transformer, t 1 , conver ts the 50 ? differential output to 50 ? single-ended. c17 and c18 are dc blocks. l1 and l2 provide dc bias for the output. c17, c18 = 100 pf (size 0603) t1 = etc1-1-13 (m/a-com) l1, l2 = 120 nh (size 0603) l3, l4, c5, c6 input interface . the input impedance of the ad8341 requires 1.2 nh inductors in series with rfip and rfim for optimum return loss w h en d r iven by a single-e nd ed 50 ? line. c5 and c6 are dc blocks. l3, l4 = 1.2 nh (size 0402) c5, c6 = 100 pf (size 0603)
ad8341 rev. 0 | page 18 of 20 components function default conditi o ns c2, c4, c7, c9, c14, c1, c3, c8, c10, r2, r4, r5, r6 supply dec o up ling . c2, c4, c7, c9, c 14 = 0.1 f (size 0603) c1, c3, c8, c10 = 100 pf (size 0603) r2, r4, r5, r6 = 0 ? (size 0603) r8, sw1 output disable interface . the output stage of the ad8341 is di sabled by applyi ng a high voltage to the dsop pin by moving sw1 to po sition b. the output stage is enabled moving sw1 to position a. the output di sable function c a n als o be ex erc i sed by applyin g an exter- nal high or low voltage to the dsop sma connector with sw1 in position a. r8 = 10 k? (size 0603) sw1 = spdt (po s ition a, output enabled) 04700-041 ibbp ibbm vps2 dsop qbbp qbbm vps2 vps2 vprf cmrf rfin rfip cmop cmop rfom rfop q f l p qflm cmop cmop cmrf vprf iflp iflm ad8341 c12 (open) c11 (open) c8 100pf l3 1.2nh c6 100pf l4 1.2nh c5 100pf ibbm ibbp vs rfin vp qbbp qbbm l2 120nh l1 120nh c14 0.1 f c10 100pf c9 0.1 f vp c17 100pf c18 100pf rfop b a c1 100pf c7 0.1 f r5 0 ? r4 0 ? c3 100pf c4 0.1 f t1 etc1-1-13 m/a-com sw1 r8 10k ? r2 0 ? c2 0.1 f vp test point gnd test point dsop vs r14 4k ? r11 2k ? r15 44k ? c15 0.1 f w4 r21 0 ? r19 0 ? w3 r20 0 ? r9 (open) r7 (open) c19 0.1 f vs r12 4k ? r10 2k ? r13 44k ? r6 0 ? c16 0.1 f w2 r17 0 ? r16 0 ? w1 r18 0 ? r1 (open) r3 (open) c20 0.1 f f i g u re 41. ev aluat i on b o a r d s c h e m a t i c
ad8341 rev. 0 | page 19 of 20 04700-042 f i g u re 42. co mpon ent sid e lay o ut 04700-043 f i g u re 43. co mpon ent sid e s ilk s c r e e n
ad8341 rev. 0 | page 20 of 20 outline dimensions 1 24 6 7 13 19 18 12 2.25 2.10 sq 1.95 0.60 max 0.50 0.40 0.30 0.30 0.23 0.18 2.50 ref 0.50 bsc 12 max 0.80 max 0.65 typ 0.05 max 0.02 nom 1.00 0.85 0.80 seating plane pin 1 indica t o r to p view 3.75 bsc sq 4.00 bsc sq pin 1 indicator 0.60 max coplanarity 0.08 0.20 ref 0.25 min exposed pad (bottom view) compliant t o jedec st and ards mo-220-v ggd-2 f i gure 44. 2 4 -l ead l e ad f r a m e ch ip s c a l e p a ck ag e [lfcs p ] 4 mm 4 m m b o d y (cp - 2 4 -1) di me nsio ns sho w n i n mi ll im e t e r s ordering guide model temperature r a nge package descri pt ion package option ord e r mu ltiple ad8341acpz-w p 1 , 2 ?40c to +85c 24-lead lead fr ame ch ip scale package (lfcsp) cp-24-1 64 ad8341acpz-r eel7 2 ?40c to +85c 24-lead lead fr ame ch ip scale package (lfcsp) cp-24-1 1,500 ad8341-eval evaluation boar d 1 1 w p = w a ff le pack . 2 z = pb-free part. ? 2004 a n alo g devic e s, inc. all rig h ts res e rve d . t r ade m arks a n d re g i s - tered trade m arks are the property of their respective owners . d04700C0C 7/04(0)

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