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50 mhz to 3.5 ghz, 45 db rf detector ad8312 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. 461. 31 13 ? 2005 analog de vices, i n c. al l r i ght s r e ser v ed . features complete rf detector function typical range: ?45 dbm to 0 d b m, re 50 ? frequency r e s p onse from 50 mhz to 3.5 gh z temperature- s table linear -in- db response accurate to 3.5 ghz rapid response: 85/120 ns (ri s e/fall) low power: 12 mw at 2. 7 v applic ati o ns cellular hands e ts (gsm, cdm a , wcdma) rssi and tssi f o r wireless ter m inal de vices transmitter power measurem ent general description the ad8312 is a co m p lete , lo w cos t s u bsys tem f o r th e m e as ur e m en t o f rf sig n als in t h e f r e q uen c y ra n g e o f 50 mh z t o 3.5 gh z . i t has a ty p i ca l dy na m i c r a n g e o f 45 d b a nd is i n te nde d f o r us e in a wide va r i ety o f ce l l u l a r ha n d s e ts and o t h e r wir e less de vices. i t p r o v i d es a wi der d y n a mic r a n g e an d b e t t er acc u r a c y t h a n p o ss i b le us in g di s c r e te dio d e de te c t o r s. i n p a r t ic u l a r , i t s t e m p era t ur e s t ab i l i t y is exce l l e n t o v er t h e f u l l o p era t i n g ra n g e o f ?40c t o +85c. i t s hig h s e n s i t iv i t y al lo ws m e asur em e n t a t lo w p o w e r le ve ls, th us r e d u ci n g t h e a m o u n t o f po w e r th a t n eed s t o b e co u p l e d t o t h e det e c t o r . i t is ess e n t ia l l y a vol t age-r e sp on d i n g de vic e , w i t h a typ i c a l sig n al ran g e o f 1.25 mv t o 224 mv r m s o r ?45 db m t o 0 db m, r e 50 ?. f o r co n v enie n c e , t h e sig n a l is i n t e r n a l ly ac-co u ple d , usin g a 5 pf ca p a ci t o r to a lo ad o f 3 k? in sh u n t wi th 1. 3 pf . this hig h - p a s s co u p ling, wi th a co r n er a t a p p r o x ima t e l y 16 mh z, det e r m i n es t h e l o w e s t o p er a t i n g f r e q uen c y . th e r efo r e , t h e s o ur ce ma y be dc g r o u n d e d . the ad8312 ou t p u t , v o ut , in c r eas e s f r o m c l os e t o g r o u n d t o a b o u t 1.2 v bec a us e t h e in p u t sig n al lev e l in cr eas e s f r o m 1.25 mv t o 224 mv . a ca p a c i t o r ma y b e co nn ec t e d betw een t h e v o u t an d cf l t p i ns w h e n i t i s desir a b l e to i n cr e a s e t h e t i me in t e r v a l o v er w h ich a v era g in g o f t h e i n p u t w a vefo r m o c c u rs. the ad8312 is a v a i la b l e in a 6-bal l , 1.0 mm 1.5 mm, wa f e r - lev e l c h i p s c ale p a c k a g e and con s u m es 4.2 ma f r o m a 2.7 v t o 5.5 v s u p p l y . func tio n a l block di agram 05260- 001 10db det 10db det 10db det 10db det det + ? cflt rfin comm offset compensation v-i vset band-gap reference vpos i-v vout ad8312 fi g u r e 1 .
ad8312 rev. 0| page 2 of 20 table of contents specifications ..................................................................................... 3 absolute maximum ratings ............................................................ 6 esd caution .................................................................................. 6 pin configuration and function descriptions ............................. 7 typical performance characteristics ............................................. 8 general description ....................................................................... 12 applications ..................................................................................... 13 basic connections ...................................................................... 13 transfer function in terms of slope and intercept ............... 13 filter capacitor ....................................................................... 14 input coupling options ........................................................ 14 increasing the logarithmic slope ........................................ 15 effect of waveform type on intercept ................................ 15 temperature drift .................................................................. 16 operation above 2.5 ghz .................................................... 16 device handling ..................................................................... 16 evaluation board .................................................................... 16 outline dimensions ....................................................................... 19 ordering guide .......................................................................... 19 revision history 4/05revision 0: initial version
ad8312 rev. 0| page 3 of 20 specifications v s = 3 v, cflt = open, t a = 25c, light condition = 600 lux, 52.3 ? termination resistor at rfin, unless otherwise noted. table 1. parameter conditions min typ max unit signal input interface rfin (pin 6) specified frequency range 0.05 3.5 ghz input voltage range internally ac-coupled 1.25 224 mv rms equivalent power range 52.3 ? exte rnal termination ?45 0 dbm dc resistance to comm 100 k? measurement mode vout (pin 2) shorted to vs et (pin 3), sinusoidal input signal f = 50 mhz input impedance 3050 || 1.4 ? || pf 1 db dynamic range t a = 25c 50 db ?40c < t a < +85c 42 db maximum input level 1 db error 3 dbm minimum input level 1 db error ?47 dbm slope 20.25 mv/db intercept ?51.5 dbm output voltagehigh power in p in = ?10 dbm 0.841 v output voltagelow power in p in = ?40 dbm 0.232 v temperature sensitivity p in = ?10 dbm 25c t a +85c 0.0010 db/c ?40c t a +25c 0.0073 db/c f =100 mhz input impedance 2900 || 1.3 ? || pf 1 db dynamic range t a = 25c 48 db ?40c < t a < +85c 40 db maximum input level 1 db error 2 dbm minimum input level 1 db error ?46 dbm slope 19.0 21.0 23.0 mv/db intercept ?56.0 ?50.5 ?47.0 dbm output voltagehigh power in p in = ?10 dbm 0.850 v output voltagelow power in p in = ?40 dbm 0.222 v temperature sensitivity p in = ?10 dbm 25c t a +85c 0.0002 db/c ?40c t a +25c 0.0060 db/c f = 900 mhz input impedance 890 || 1.15 ? || pf 1 db dynamic range t a = 25c 49 db ?40c < t a < +85c 42 db maximum input level 1 db error 1 dbm minimum input level 1 db error ?48.0 dbm slope 20.25 mv/db intercept ?51.9 dbm output voltagehigh power in p in = ?10 dbm 0.847 v output voltagelow power in p in = ?40 dbm 0.237 v temperature sensitivity p in = ?10 dbm 25c t a 85c 0.0019 db/c ?40c t a +25c 0.0010 db/c
ad8312 rev. 0| page 4 of 20 parameter conditions min typ max unit f = 1.9 ghz input impedance 450 || 1.13 ? || pf 1 db dynamic range t a = 25c 48 db ?40c < t a < +85c 40 db maximum input level 1 db error 1 dbm minimum input level 1 db error ?47 dbm slope 19.47 mv/db intercept ?52.4 dbm output voltage ? high power in p in = ?10 dbm 0.826 v output voltage ? low power in p in = ?40 dbm 0.240 v temperature sensitivity p in = ?10 dbm 25c t a 85c 0.004 db/c ?40c t a +25c 0.005 db/c f = 2.2 ghz input impedance 430 || 1.09 ? || pf 1 db dynamic range t a = 25c 48 db ?40c < t a < +85c 40 db maximum input level 1 db error 1 dbm minimum input level 1 db error ?47 dbm slope 19.1 mv/db intercept ?52.1 dbm output voltagehigh power in p in = ?10 dbm 0.803 v output voltagelow power in p in = ?40 dbm 0.230 v temperature sensitivity p in = ?10 dbm 25c t a 85c ?0.0023 db/c ?40c t a +25c 0.0055 db/c f = 2.5 ghz input impedance 400 || 1.03 ? || pf 1 db dynamic range t a = 25c 49 db ?40c < t a < +85c 40 db maximum input level 1 db error 1 dbm minimum input level 1 db error ?48 dbm slope 18.6 mv/db intercept ?51.2 dbm output voltagehigh power in p in = ?10 dbm 0.762 v output voltagelow power in p in = ?40 dbm 0.204 v temperature sensitivity p in = ?10 dbm 25c t a 85c 0.005 db/c ?40c t a +25c ?0.0126 db/c output interface vout (pin 2) minimum output voltage no signal at rfin, r l 10 k? 0.02 0.2 v maximum output voltage 1 r l 10 k? 1.8 2.0 v general limit 2.7 v v s 5.5 v v s ? 1.2 v s ? 1 v available output current sourci ng/sinking 2/0.1 ma residual rf (at 2f) f = 0.1 ghz (worst condition) 100 v output noise rf input = 2.2 ghz, ?10 dbm, f noise = 100 khz, cflt open 1.4 v/hz fall time input level = off to 0 dbm, 90% to 10% 120 ns rise time input level = 0 dbm to off, 10% to 90% 85 ns vset interface vset (pin 3) input resistance 13 k? bias current source rfin = ?10 dbm; vset = 1.2 v 75 a
ad8312 rev. 0| page 5 of 20 parameter conditions min typ max unit power interface vpos (pin 1) supply voltage 2.7 3.0 5.5 v quiescent current 2.8 4.2 5.7 ma vs. temperature ?40c t a +85c 4.3 ma 1 increased output is possible when using an attenuator between vout and vset to raise the slope.
ad8312 rev. 0| page 6 of 20 absolute maximum ratings table 2. p a r a m e t e r v a l u e supply voltage vpos 5.5 v vout, vse t 0 v, vpos input voltage 1.6 v rms equivalent power 17 dbm internal power dissipation 200 mw ja (wlcsp) 200c/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 list e d u nde r a b s o l u te m a xim u m r a t i n g s ma y ca us e p e r m a n e n t dama ge to t h e de vi ce. t h is is a st r e ss r a t i ng on ly ; f u n c t i on a l op e r at i o n of t h e d e v i c e a t t h e s e or an y o t h e r con d i t ions 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 pl ie d . e x p o sur e t o a b s o l u te max i m u m r a t i ng co ndi t i on s fo r ex tende d p e r i o d s ma y a f fe c t de vice rel i a b i l i t y . esd caution esd (electrostatic discharge) se nsit ive device . electrostatic charges as hig h as 4000 v readily accumulate on the human bod y and test eq uipment and can discharge wi thout detection. although this product features proprietary esd protection circ uitry, permanent dama ge may occur on devices subjected to high energy electrostatic di scharge s . ther efore, pro p er esd precautions are rec o m m ended to avoid performan c e degradation or l o ss of functiona l ity.
ad8312 rev. 0| page 7 of 20 pin conf iguration and fu nction descriptions 05260- 002 1 vpos 6 rfin 2 vout 5 comm 3 vset 4 cflt ad8312 top view (not to scale) f i gure 2. pin config ur ation ta ble 3. pi n f u nct i on d e s c ri pt i o ns ball o. mnemonic description 1 vpos positive supply voltage (v s ), 2.7 v to 5.5 v. 2 vout logarithmic output. o utput voltage increa ses wi th in creasing input amplitude. 3 vset setpoint input. connect vset t o vout for measurem ent-mode operation. t h e nomina l logar i thmic sl ope of 20 mv/db can be increas e d to an arbitrarily hig h valu e by attenuating the signal between vout and vset (see the increasi ng the logarithmic slope sectio n). 4 cflt connection for an external capacitor to slow the response of the output. capacitor is connected between cflt and vout. 5 comm device common (ground). 6 rfin rf input.
ad8312 rev. 0| page 8 of 20 typical perf orm ance cha r acte ristics v s = 3 v ; t a = 25c; c fl t = o p en; lig h t condi t i o n = 600 l u x, 5 2 .3 ? t e r m ina t io n; unles s o t h e r w is e n o t e d . c o l o rs: +25c = b l ac k, ?40c = b l ue , + 85c = re d . 1.25 1.00 0.75 0.50 0.25 0 ?60 ? 50 ?40 ? 30 ?20 ? 10 0 1 0 05260-003 p in (dbm) vou t ( v ) 2.5 e rror (db) ?2.5 ?2.0 ?1.5 ?1.0 ?0.5 0 0.5 1.0 1.5 2.0 +85 c +25 c ?40 c f i g u re 3. v o u t and l o g conf or ma nc e v s . input a m plit ud e at 50 m h z; t y pi c a l de vi c e a t ?4 0 c, +25 c, a n d +8 5 c 1.25 1.00 0.75 0.50 0.25 0 ?60 ? 50 ?40 ? 30 ?20 ? 10 0 1 0 05260-004 p in (dbm) vou t ( v ) 2.5 e rror (db) ?2.5 ?2.0 ?1.5 ?1.0 ?0.5 0 0.5 1.0 1.5 2.0 +85 c +25 c ?40 c f i g u re 4. v o u t and l o g conf or ma nc e v s . input a m plit ud e at 10 0 m h z; t y pi c a l de vi c e a t ?4 0 c, +25 c, a n d +8 5 c 1.25 1.00 0.75 0.50 0.25 0 ?60 ? 50 ?40 ? 30 ?20 ? 10 0 1 0 05260-005 p in (dbm) vou t ( v ) 2.5 e rror (db) ?2.5 ?2.0 ?1.5 ?1.0 ?0.5 0 0.5 1.0 1.5 2.0 +85 c +25 c ?40 c f i g u re 5. v o u t and l o g conf or ma nc e v s . input a m plit ud e at 90 0 m h z; t y pi c a l de vi c e a t ?4 0 c, +25 c, a n d +8 5 c 1.25 1.00 0.75 0.50 0.25 0 ?60 ? 50 ?40 ? 30 ?20 ? 10 0 1 0 05260-006 p in (dbm) vou t ( v ) 2.5 e rror (db) ?2.5 ?2.0 ?1.5 ?1.0 ?0.5 0 0.5 1.0 1.5 2.0 +85 c +25 c ?40 c f i gure 6 . vout a n d l o g c o nf o r m a nc e vs . input a m pl i t ud e a t 1 . 9 gh z; t y pi c a l de vi c e a t ?4 0 c, +25 c, a n d +8 5 c 1.25 1.00 0.75 0.50 0.25 0 ?60 ? 50 ?40 ? 30 ?20 ? 10 0 1 0 05260-007 p in (dbm) vou t ( v ) 2.5 e rror (db) ?2.5 ?2.0 ?1.5 ?1.0 ?0.5 0 0.5 1.0 1.5 2.0 +85 c +25 c ?40 c f i gure 7 . vout a n d l o g c o nf o r m a nc e vs . input a m pl i t ud e a t 2 . 2 gh z; t y pi c a l de vi c e a t ?4 0 c, +25 c, a n d +8 5 c 1.25 1.00 0.75 0.50 0.25 0 ?60 ? 50 ?40 ? 30 ?20 ? 10 0 1 0 05260-008 p in (dbm) vou t ( v ) 2.5 e rror (db) ?2.5 ?2.0 ?1.5 ?1.0 ?0.5 0 0.5 1.0 1.5 2.0 +85 c +25 c ?40 c f i gure 8 . vout a n d l o g c o nf o r m a nc e vs . input a m pl i t ud e a t 2 . 5 gh z; t y pi c a l de vi c e a t ?4 0 c, +25 c, a n d +8 5 c
ad8312 rev. 0| page 9 of 20 2.5 ?2.5 ?2.0 ?1.5 ?1.0 ?0.5 0 0.5 1.0 1.5 2.0 ?60 ? 50 ?40 ? 30 ?20 ? 10 0 1 0 05260- 009 p in (dbm) error (d b) +85 c +25 c ?40 c f i gure 9. d i s t ributi on of e rror at ?4 0 c, +2 5c , a n d + 8 5 c af ter a m bi ent nor m al iz at io n v s . input a m pl it ude at 50 m h z f o r 8 0 d e v i c e s 2.5 ?2.5 ?2.0 ?1.5 ?1.0 ?0.5 0 0.5 1.0 1.5 2.0 ?60 ? 50 ?40 ? 30 ?20 ? 10 0 1 0 05260- 010 p in (dbm) error (d b) +85 c +25 c ?40 c f i g u re 10. d i s t r i but i on of e r r o r at ? 4 0 c, +2 5c , a n d + 8 5 c af ter a m bi ent nor m al iz at io n v s . input a m pl it ude at 10 0 m h z f o r 80 d e v i c e s 2.5 ?2.5 ?2.0 ?1.5 ?1.0 ?0.5 0 0.5 1.0 1.5 2.0 ?60 ? 50 ?40 ? 30 ?20 ? 10 0 1 0 05260- 011 p in (dbm) error (d b) +85 c +25 c ?40 c f i g u re 11. d i s t r i but i on of e r r o r at ? 4 0 c, +2 5c , a n d + 8 5 c af ter a m bi ent nor m al iz at io n v s . input a m pl it ude at 90 0 m h z f o r 80 d e v i c e s 2.5 ?2.5 ?2.0 ?1.5 ?1.0 ?0.5 0 0.5 1.0 1.5 2.0 ?60 ? 50 ?40 ? 30 ?20 ? 10 0 1 0 05260- 012 p in (dbm) error (d b) +85 c +25 c ?40 c f i g u re 12. d i s t r i but i on of e r r o r at ? 4 0 c, +2 5c , a n d + 8 5 c af ter a m bi ent nor m al iz at io n v s . input a m pl it ude at 1.9 gh z f o r 8 0 d e v i c e s 2.5 ?2.5 ?2.0 ?1.5 ?1.0 ?0.5 0 0.5 1.0 1.5 2.0 ?60 ? 50 ?40 ? 30 ?20 ? 10 0 1 0 05260- 013 p in (dbm) error (d b) +85 c +25 c ?40 c f i g u re 13. d i s t r i but i on of e r r o r at ? 4 0 c, +2 5c , a n d + 8 5 c af ter a m bi ent nor m al iz at io n v s . input a m pl it ude at 2.2 gh z f o r 8 0 d e v i c e s 2.5 ?2.5 ?2.0 ?1.5 ?1.0 ?0.5 0 0.5 1.0 1.5 2.0 ?60 ? 50 ?40 ? 30 ?20 ? 10 0 1 0 05260- 014 p in (dbm) error (d b) +85 c +25 c ?40 c f i g u re 14. d i s t r i but i on of e r r o r at ? 4 0 c, +2 5c , a n d + 8 5 c af ter a m bi ent nor m al iz at io n v s . input a m pl it ude at 2.5 gh z f o r 8 0 d e v i c e s
ad8312 rev. 0| page 10 of 2 0 05260- 015 vout rf input pulsed rf 0.1ghz, 0dbm 200mv/vert div fall time 120ns rise time 85ns 500mv/ vert div 100ns/horiz div f i g u re 15. v o u t r e s p ons e ti me , r f o f f to 0 db m 05260- 016 ad8312 nc = no connect rfin 1 comm 2 cflt 3 vpos 6 vout 5 vset nc 4 0.1 f 3v tektronix tds51504 scope *50 ? termination rohde & schwarz smt06 generator pulse modulation rf out +3db trig out rf splitter 52.3 ? ?3db ? 3db ch1 ch3* trig f i gure 16. t e s t s e tu p for p u ls e r e s p ons e 05260-017 12 0.5 0.2 ?j 1 ? j0.5 ? j0.2 0 +j0.2 +j0.5 +j1 +j2 2.2ghz 3.5ghz ?j 2 0.1ghz 0.9ghz 1.9ghz 2.5ghz f i gure 17. input i m pedance v s . f r eque nc y ; no t e r m inat io n r e sisto r on r f in 05260- 018 vpos 1 s/horiz div 500mv/vert div 2v/vert div vout fi g u r e 1 8 . po w e r - o n a n d po w e r - o f f r e s p o n s e 05260-019 ad8312 nc = no connect rfin 1 comm 2 cflt 3 vpos 6 vout 5 vset nc 4 ad811 732 ? hp8648b signal generator 20dbm hp8116a pulse generator tektronix tds784c scope tektronix p6204 fet probe pulse out 49.9 ? trig out trig rf out 10mhz ref output ext trig 52.3 ? f i gur e 1 9 . t e st s e tup fo r p o wer - o n a n d p o wer - o ff resp onse 10k 1k 100 10 1 1 3 10 30 100 300 1k 3k 10k 05260-020 frequency (khz) no ise spect ral densit y (n v/ hz) 0dbm ? 10dbm ? 20dbm ? 40dbm ? 60dbm rf off f i gure 20. no ise s p ec tr a l d e ns it y of o u tput; cfl t = o p en
ad8312 rev. 0| page 11 of 2 0 table 4. typ i cal sp ecification s at sele cted frequen c ies at 25c (mean and ) 1 db dynamic range 1 (dbm) slope (mv/db) intercept (dbm) high po int low point frequenc y (gh z ) 0.05 20.25 0.3 ?51.5 0 . 4 + 3 . 0 0 . 1 2 ? 4 8 . 0 0 . 1 3 0 . 1 2 1 . 0 0 . 2 ? 5 0 . 5 0 . 4 + 2 . 0 0 . 1 ? 4 6 . 0 0 . 1 0.9 20.25 0.3 ?51.9 0.4 +0.2 0.1 ?49.0 0.2 1.9 19.47 0.3 ?52.4 0.6 +1.5 0.12 ?48.8 0.3 2 . 2 1 9 . 1 0 . 4 ? 5 2 . 1 0 . 8 5 + 1 . 5 0 . 2 ? 4 8 . 5 0 . 4 2.5 18.6 0.6 ?51.2 1.2 +2.0 0.3 ?47.7 0.5 3 . 0 1 7 . 5 0 . 7 ? 4 6 . 9 2 . 5 ? 4 0 . 3 ? 4 6 0 . 4 3 . 5 1 7 . 1 0 . 7 ? 4 2 . 6 2 . 5 ? 1 0 . 3 ? 3 9 0 . 3 1 refer to figure 23.
ad8312 rev. 0| page 12 of 2 0 gene ral description the ad8312 is a loga r i thmic am p l if ier (log a m p) simi la r in desig n t o t h e ad8313; f u r t h e r deta ils abo u t t h e s t r u c t ur e an d f u n c tion ma y b e f o un d in t h e ad8313 da t a she e t an d t h e da t a s h e e ts o f o t h e r l o g a m p l if iers p r o d uce d b y ad i. f i gur e 21 sh o w s t h e ma i n fe a t ur es o f t h e a d 831 2 in b l o c k s c h e ma t i c fo r m . the ad8312 com b in es tw o k e y f u n c tio n s neede d f o r th e m e a s ur e m en t o f sig n a l le vel o v e r a m o der a tely wi de d y na mic ra n g e . f i rst, i t pr o v ides t h e am plif ica t ion n e e d e d t o r e sp on d t o smal l sig n als in a c h a i n o f fo ur a m p l if ier/limi t e r ce l l s, e a c h ha vin g a sma l l-s i g n a l ga i n o f 10 db an d a b a n d w i d t h o f a p p r o x im a t e l y 3.5 gh z . a t t h e ou t p ut o f e a ch am plif ier st a g e is a full - w a v e r e ctif i e r , e s se n t i a ll y a sq u a r e -l a w d e t e ct o r c e ll , wh i c h co n v er ts t h e rf sig n al v o l t a g es t o a f l uc t u a t i n g c u r r en t w i t h a n a v era g e val u e t h a t i n cr e a s e s w i t h sig n al le ve l . a f u r t h e r p a s s i v e dete c t o r st a g e is adde d a h e a d o f t h e f i rst st a g e. ther efo r e, t h er e a r e f i ve dete c t o r s, e a ch s e p a r a te d b y 10 db , sp annin g s o m e 50 db o f d y na mic ra n g e . th e o v era l l acc u rac y a t t h e ext r em es o f th i s t o tal ra n g e , v i ew ed as t h e devia t i o n f r o m a n i d e a l loga r i t h mic r e sp o n s e , t h a t is, t h e la w-co nfo r ma n c e er r o r , ca n b e j u d g e d b y re f e re nc e to f i g u re 3 t h rou g h f i g u re 8 , w h i c h s h ow t h a t er r o rs acr o s s t h e ce n t ral 40 db a r e m o der a te . th es e f i gur e s s h o w h o w t h e c o nf o r ma n c e t o a n ide a l loga r i t h mic f u n c tio n va r i es w i t h t e m p era t ur e a nd f r e q uen c y . the o u t p u t o f t h es e de t e c t o r cel l s is in t h e fo r m o f a dif f er en t i al c u r r en t, ma k i n g t h e i r summ a t ion a si m p le m a tter . i t ca n e a si ly b e s h o w n t h at s u c h s u m m at i o n c l o s e l y ap p r ox i m at e s a loga ri th m i c fun c ti o n . th i s r e s u l t i s th e n co n v e r t e d t o a v o l t a g e a t t h e v o ut p i n th r o ug h a hi g h ga i n s t a g e . i n m e as ur em en t mo de s , t h i s output i s c o n n e c te d b a ck to a volt age - to - c u r re n t (v -t o-i) s t a g e , in s u c h a ma nn er tha t v o ut is a loga r i thmic m e as ur e o f t h e rf in p u t v o l t a g e w i t h a s l op e and in t e r c ept co n t r o l l e d b y t h e desig n . f o r a f i xe d ter m i n a t ion r e sist an ce a t th e in p u t o f t h e ad8312, a g i ven v o l t a g e co r r es p o n d s t o a c e r t ai n p o we r l e vel. the ext e r n al ter m ina t io n adde d bef o r e the ad8 312 det e r m in es t h e ef fe c t i v e p o w e r s c al in g . this o f t e n t a k e s t h e fo r m o f a sim p le r e sis t o r (52.3 ? p r o v ides a net 50 ? in p u t), b u t m o r e el a b or a t e m a tch i ng ne t w or k s m a y b e u s e d . t h i s i m p e d a nc e det e r m i n es t h e l o ga r i t h mic i n t e r c ep t, t h e in pu t p o w e r fo r w h ich th e o u t p u t w o uld cr os s th e ba s e li n e (v o u t = 0) i f th e fun c t i o n w e r e co n t i n uo us fo r a l l va l u es o f in p u t. si n c e t h is is ne v e r t h e cas e fo r a p r ac t i cal log a m p , t h e in t e r c ep t r e fers t o t h e val u e o b ta in e d b y t h e m i n i m u m - e r r o r , s t ra i g h t - l in e f i t t o th e a c t u al g r a p h of v o u t v s . in pu t p o we r . the qu ote d v a lu e s assu me a sin u s o idal (c w ) sig n al . w h er e t h er e is com p le x m o d u la t i o n , as i n c d ma , t h e cal i b r a t i o n o f th e po w e r r e s p o n s e n eeds t o b e ad j u s t e d acco r d in g l y . w h er e a t r ue p o w e r (wa v efo r m- i n d e pen d en t ) r e s p o n s e i s n eed e d , t h e use o f a n rm s - r e s p o n di n g det e c t o r , s u c h as th e ad8361, sh o u ld be con s ider ed . h o w e v e r , i n t e rm s o f th e l o g a ri th m i c s l o p e , th e a m o u n t b y w h ic h t h e out p u t v o u t changes for e a ch de c i b e l of in pu t cha n ge (v ol t a ge o r p o w e r), is, in p r in c i ple , i nde p e nde n t o f wa v e fo r m o r t e r m ina t io n im p e d a n c e . i n p r ac t i c e , i t usua l l y fa l l s o f f a t hig h er f r e q uen c ies b e ca us e o f t h e de cli n ing ga in o f t h e a m plif ier st a g es a nd o t h e r ef fe c t s in t h e dete c t o r ce l l s. f o r t h e ad8312, t h e s l op e a t lo w f r eq uen c ies is n o mina l l y 21.0 mv/db , fal l in g a l m o s t lin e a r l y wi th f r eq uen c y t o a b o u t 18.6 mv/db a t 2.5 gh z. th es e val u es a r e s e n s ib l y indep e nde n t o f t e m p era t ur e and al m o s t to t a l l y una f f e c t e d b y s u p p l y v o l t a g es o f 2. 7 v t o 5 . 5 v . 05260- 021 10db det 10db det 10db det 10db det det + ? cflt rfin comm offset compensation v-i vset band-gap reference vpos i-v vout ad8312 f i gure 21. block s c hematic
ad8312 rev. 0| page 13 of 2 0 appli c ations basic connections f i gur e 22 sh o w s th e basic co nn e c tio n s fo r m e asur em e n t m o de . a s u p p l y v o l t a g e o f 2.7 v t o 5.5 v is r e q u ir ed . the s u p p l y t o t h e vpos p i n sh o u l d b e de co u p le d wi t h a lo w i n d u c t a n c e 0.1 f s u r f ace-m o u n t cera mic c a p a ci to r . a s e r i es r e sis t o r o f a b o u t 10 ? ma y b e ad de d; t h is re s i stor sl ig h t ly re d u c e s t h e s u p p ly vol t age to th e ad8312 (maxim u m c u r r en t in t o the vpos p i n is ap p r ox i m at e l y 5 . 7 m a ) . i t s u s e s h o u l d b e av o i d e d i n a p plic a t io n s w h er e t h e p o w e r su p p ly v o l t a g e is v e r y lo w (t ha t is, 2.7 v). a s e r i es ind u c t o r p r o v ides simi la r p o w e r s u p p l y f i l t er ing wi t h min i ma l d r o p in su p p ly vol t a g e. 05260- 022 ad8312 c f optional (see text) optional (see text) vout rfin 1 comm 2 cflt 3 vpos 6 vout 5 vset 4 v s input 0.1 f 52.3 ? f i gure 22. bas i c connec t ions for o p e r at io n i n m e as urem ent m o d e the ad8312 has a n in t e r n al in p u t co u p lin g c a p a ci t o r . this e l im in a t es t h e ne e d fo r ext e r n a l ac co u p ling. i n t h is exa m ple , a b r o a d b and i n p u t ma tch is achi e v e d b y co nn e c t i n g a 52.3 ? r e sis t o r betw een rfi n and g r o u nd . this r e sis t a n ce co m b i n es wi t h t h e in t e r n al i n p u t im p e dan c e o f a p p r o x ima t e l y 3 k? t o g i v e a n o v eral l b r o a d b and in p u t r e sis t an ce o f 50 ?. s e v e ral o t h e r cou p lin g m e t h o d s a r e p o s s i b le; t h es e a r e des c r i b e d i n t h e i n p u t c o u p l i n g o p t i o n s s e c t ion. t h e m e a s ur em en t m o de i s s e l e c t ed b y co nn ectin g v s et t o v o u t , w h i c h e s t a b l i s h e s a f e ed b a c k pa th a n d se t s th e loga r i t h mic s l op e t o i t s n o minal val u e . th e p e ak v o l t a g e ra n g e o f th e m e as ur em en t ext e n d s f r o m ?49 db m t o 0 db m a t 0 . 9 g h z and is on ly sl ig h t ly l e ss a t hi g h e r f r e q u e nc ie s u p to 2.5 gh z. a t a s l o p e o f 21.0 mv/db , this w o u l d am o u n t t o an o u t p u t s p a n o f 1.029 v . f i gur e 23 s h o w s t h e tran sf er f u n c tio n for v o u t a t a s u pply volt age of 2 . 7 v an d an i n put f r e q u e nc y of 900 mh z. the lo ad r e sis t an ce on v o ut sh o u ld n o t b e lo w e r tha n 4 k? s o th a t t h e full-sca le o u t p u t ca n be g e n e ra t e d wi th th e li mi t e d a v a i la b l e c u r r en t o f 1 ma max i m u m. f i gur e 23 sho w s t h e lo ga r i t h mic co n f o r ma n c e u n der t h e s a me con d i t io n s . 1.2 1.0 0.8 0.6 0.4 0.2 0 ?60 ? 50 ?40 ? 30 ?20 ? 10 0 1 0 05260-023 p in (dbm) vout (v) 3 2 1 0 ?1 ?2 error (db) ?3 intercept 3db dynamic range 1db dynamic range v s = 2.7v rt = 52.3 ? f i gure 2 3 . vout an d l o g c o nf o r m a nce erro r vs . input l e vel vs. inpu t l e vel at 900 m h z trans f er functi on in terms of s l ope an d intercep t the tra n sf er f u n c tion o f t h e ad8312 is c h a r ac t e r i ze d in t e r m s o f i t s s l o p e an d in t e r c ep t. th e l o ga r i t h mic s l o p e is def i n e d as t h e c h a n g e in t h e rss i o u t p u t v o l t ag e f o r a 1 db c h a n g e a t t h e in p u t. f o r th e ad8312 , th e s l o p e is n o minal l y 20 mv/db . ther ef o r e , a 10 db cha n ge a t t h e in p u t r e su l t s in a cha n ge a t t h e ou t p u t o f a p p r o x ima t e l y 200 mv . f i gur e 2 3 s h o w s t h e ra ng e o v er which th e d e v i ce m a in ta i n s i t s co n s ta n t s l o p e . th e d y na m i c ra n g e ca n b e def i ne d as t h e ra n g e o v er w h ich t h e er r o r r e ma in s w i t h i n a cer t a i n b a nd , usua l l y 1 db o r 3 db . i n f i gure 23, fo r ex a m ple, t h e 1 db d y namic r a n g e is a p p r o x ima t ely 51 db (f r o m ?49 dbm to +2 dbm). the i n t e r c ept is t h e p o i n t a t w h i c h t h e ext r a p ola t e d line a r r e sp o n s e w o u l d in t e rs e c t t h e h o r i zo n t a l axis (s e e f i gur e 23). u s in g t h e s l o p e a nd i n t e r c ept, t h e o u t p ut v o l t a g e ca n b e ca lc u l a t e d fo r a n y i n p u t l e v e l w i t h i n t h e sp e c if ie d i n p u t ra n g e b y ( ) o in slope p p v vout ? = w h er e: vou t is t h e de m o d u l a te d an d f i l t er e d rss i o u t p ut. v slope is t h e log a r i t h mic s l o p e , exp r es s e d i n v / db . p in is t h e in p u t s i g n al , exp r es s e d in de c i b e ls r e l a t i v e t o s o m e re f e re nc e l e v e l ( d bm i n t h i s c a s e ) . p o is t h e loga r i t h mic i n t e r c e p t, exp r es s e d i n de cib e ls r e la t i v e t o t h e s a me re f e re nc e l e ve l. f o r e x am pl e, a t an i n put l e vel of ? 2 7 dbm, t h e out p ut vol t age i s ( ) [ ] v 0.46 dbm 50 dbm 27 v/db 0.020 = ? ? ? = vout
ad8312 rev. 0| page 14 of 2 0 filter capacit o r the v i de o b a ndwi d t h o f v o u t is a p p r o x ima t ely 3.5 mh z. i n cw a p plic a t io ns w h er e t h e i n pu t f r e q uen c y is m u ch hig h er th a n th i s , n o fur t h e r f i l t e r i n g o f th e d e m o d u la t e d si gn al i s r e q u ir e d . w h ere t h er e is a lo w f r e q uen c y m o d u la t i on o f t h e c a r r i e r am pl it u d e, ho w e ve r , t h e l o w - p a ss c o r n e r m u st b e r e d u ced b y t h e addi tion o f a n ext e r n al f i l t er ca p a ci t o r , c f (see f i gur e 22). th e vide o b a n d wi d t h is r e l a t e d t o c f by () f c bandwidth video + = pf 3.5 k 13 2 1 input coupling options the in t e r n al 5 p f co u p lin g c a p a ci t o r o f th e ad8312, alo n g wi t h t h e lo w f r e q uenc y in p u t i m p e d a n c e o f 3 k?, g i ves a hig h -p ass in p u t co r n er f r e q uen c y o f a p p r o x ima t e l y 16 mhz. this s e ts t h e minim u m o p er a t in g f r eq uen c y . f i gur e 24 t o f i gur e 26 s h o w th r e e o p ti o n s f o r i n p u t co u p li n g . a b r oa d b a n d r e si s t i v e m a t c h ca n be i m p l em en t e d b y co nn ec t i n g a s h un t r e s i s t o r t o gr o u n d a t rfin (s ee f i gur e 24). this 52.3 ? r e sis t o r (o th er val u es ca n als o b e us e d t o s e le c t dif f er en t o v era l l in p u t i m p e dan c es) com b i n es wi th t h e in p u t im p e dan c e o f the ad8312 (2.9 k? || 1.3 pf) t o g i ve a b r o a db a n d i n put i m p e d a nc e of 5 0 ? . wh i l e t h e i n put r e sis t a n ce and c a p a ci tan c e (r in a nd c in ) v a r i e s b y a pprox i m a t el y 20% f r o m de vi ce to de vi ce, t h e do minan c e o f t h e ex ter n a l s h u n t r e sis t o r me a n s t h a t t h e var i a t ion i n t h e o v eral l in p u t im p e dan c e is cl os e t o t h e t o lera n c e o f t h e ex t e r n al r e sis t o r . a t f r e q uen c ies ab o v e 2 g h z, t h e in p u t i m p e dance dr o p s b e lo w 450 ?; th er ef o r e , i t is a p p r o p r i a t e t o us e a la rg er s h un t r e sis t o r va l u e . this va l u e is ca lc u l a t e d b y plo t t i n g t h e in p u t i m p e dan c e (r esist a n c e and ca p a ci t a n c e) o n a smi t h c h a r t a nd b y ch o o sing t h e b e s t sh un t r e sis t o r val u e t o b r in g t h e in p u t im p e dan c e clos es t t o t h e ce n t er o f t h e cha r t (s e e f i gur e 17). a t 2.5 gh z , a s h u n t r e sis t o r o f 57.6 ? is r e co mmende d . a r e act i ve ma t c h ca n also b e im p l em en t e d as sh o w n in f i gur e 25. this is n o t r e commende d a t lo w f r e q uen c ies b e ca us e de vic e t o lera n c es dra m a t ic al l y va r y t h e q u al i t y o f t h e ma t c h d u e t o t h e la rge in p u t r e sist an c e . f o r l o w f r e q uenc ies , f i gure 24 o r f i g u r e 26 is r e com m e n de d . i n f i gur e 25, t h e ma t c hin g com p o n en ts a r e dra w n as g e neral r e ac t a nces. d e p e nding o n t h e f r e q uen c y , t h e in p u t i m p e dan c e a t t h a t f r e q uen c y a n d t h e a v a i l a b i li ty o f st anda rd va l u e co m p o n en t s , ei t h e r a ca pa ci t o r o r a n in d u c t o r , i s used . a s in t h e p r e v io us ca s e , t h e in pu t i m p e d a n c e a t a p a r t ic u l a r f r e q uen c y is plo t te d on a sm i t h c h a r t and m a tch i n g com p on e n ts a r e ch o s e n (s h u n t o r s e r i es l, o r s h un t o r s e r i es c) t o mo v e the im p e dance t o th e cen t er o f th e c h a r t. m a t c hin g com p on en ts f o r s p ecif ic f r eq uen c ies can be calc u l a t e d usin g t h e smi t h c h a r t (s ee f i gur e 17). t a b l e 5 o u t l i n es t h e in p u t i m p e dan c es fo r s o m e co m m o n l y used f r eq ue n c i e s . th e i m p e da nc e ma tch i ng ch ar a c te r i st i c s of a re a c t i ve m a tch i ng n e tw o r k p r o v ide v o l t a g e ga in a h ead o f t h e ad8312, which i n cr ease s devi ce se n s i t i v i t y (see t a b l e 5). th e v o l t a g e ga in i s calc u l a t e d b y r1 r2 gain voltage 10 db log 20 = w h er e: r2 is the in p u t im p e dan c e o f the ad8312. r1 is the s o ur ce im p e dan c e t o which t h e ad8 312 is bein g ma tch e d . n o t e t h a t t h is g a in is o n ly ach i e v e d fo r a p e r f e c t ma t c h. c o m p o n e n t t o lera n c es and t h e us e o f s t a n da r d val u es t e nd t o re d u c e g a i n . 05260-024 50 ? source rfin r shunt 52.3 ? ad8312 v bias c in c c r in 50 ? f i gure 24. broadband resistiv e meth od for i n put c o up lin g 05260-025 50 ? source rfin x2 x1 ad8312 v bias c in c c r in 50 ? f i gure 25. na rro w - band r e ac tive met h od fo r input coup ling 05260- 026 rfin stripline ad8312 v bias c in c c r in r attn f i gure 26. s e ri es at tenuati o n m e thod for input coup ling fi g u r e 2 6 s h ow s a t h i r d m e t h o d f o r c o up l i n g t h e i n p u t s i g n a l in t o t h e ad831 2, w h ich is a p pli c a b le in a p plic a t io n s w h er e t h e in p u t sig n al is l a rg er t h a n t h e i n p u t ra n g e o f t h e log a m p . a s e r i es r e sis t o r , co nn e c t e d t o t h e rf s o ur ce , com b i n es wi t h t h e in p u t im p e dan c e o f th e ad831 2 t o r e sis t i v e l y di vide t h e in p u t sig n a l b e in g a pplie d t o t h e in pu t. this h a s t h e ad van t a g e o f v e r y li t t le p o wer be in g ta p p e d o f f in rf p o w e r tra n s m is sio n ap p l i c at i o n s .
ad8312 rev. 0| page 15 of 2 0 ta ble 5. i nput impe da nce for select f r equen c y frequenc y s11 impedanc e ? ( g h z ) r e a l i m a g i n a r y ( s e r i e s ) 0.05 0.967 ?0.043 1090 ? j 1461 0.1 0.962 ?0.081 422.6 ? j 1015 0.9 0.728 ?0.535 25.6 ? j 148.5 1.9 0.322 ?0.891 11.5 ? j 72.69 2.2 0.230 ?0.832 9.91 ? j 64.74 2.5 0.165 ?0.845 9.16 ? j 59.91 3.0 0.126 ?0.849 8.83 ? j 57.21 3.5 0.146 ?0.826 10.5 ? j 58.54 i n c r ea sing the loga r i thm i c slope the n o minal loga r i thmic s l o p e o f 20 mv/db can b e in cr eas e d t o an ar bi t r ar i l y h i g h v a lu e b y a tte n u a t i n g t h e s i g n a l b e t w e e n v o u t and v s et , as sh o w n i n f i gure 2 7 . t h e r a t i o r1 / r 2 is s e t b y 1 / ? ? ? ? ? ? ? ? ? = i n t h e exam ple s h o w n, tw o 2 k? r e sis t o r s co m b i n e t o chan g e th e s l o p e a t 190 0 mh z f r o m a p p r o x ima t e l y 20 mv/db t o 4 0 m v / d b . n o t e th a t r 2 i s i n pa ra lle l w i th th e i n p u t r e s i s t a n ce o f v s et , ty p i c a l l y 13 k?. therefo r e , t h e ex ac t r 1 / r 2 r a t i on ma y va r y . 05260- 027 ad8312 vout vset ~40mv/db @ 1900mhz r1 2k ? r2 2k ? the s l o p e can b e i n cr e a s e d t o hig h er le v e ls, as sh o w n i n f i g u re 2 8 . t h i s , ho w e ve r , re d u c e s t h e u s a b l e dy n a m i c r a nge of t h e de vi ce, d e p e ndin g on t h e sup p ly vol t a g e. ou t p u t loa d in g s h o u ld be co n s id e r ed w h en ch o o si n g r e si s t o r v a lu e s f o r sl op e a d ju st me n t to e n su re prop e r output s w i n g . n o t e t h a t the lo ad r e sis t an ce o n v o ut sh o u ld n o t be lo w e r th a n 4 k ? i n o r d e r th a t th e full- s cale o u t p u t ca n b e g e n e ra t e d wi t h t h e limi t e d a v a i la b l e c u r r en t o f 1 ma . 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0 ?60 ? 50 ?40 ? 30 ?20 ? 10 0 1 0 05260-028 p in (dbm) vou t ( v ) 3.0 2.0 1.0 5.0v supply 2.7v supply f i gure 28. vou t v s . input l e vel at v a ri ous l o ga rith mi c s l opes effect of w a veform typ e o n int e rcept al t h o u g h sp e c if ie d fo r in p u t le ve ls in dbm ( d b r e la t i v e t o 1 mw), t h e ad8312 f u ndam e n t al l y r e s p o n ds to v o l t a g e an d no t t o p o w e r . a dir e c t co n s eq uence o f this c h a r ac t e r i s t ic is tha t in p u t sig n als o f e q ual r m s p o w e r b u t dif f er in g cr es t fac t o r s, p r o d uce dif f er en t r e s u l t s a t t h e log a m plif ier s ou t p ut. the ef fe c t o f dif f er in g sig n al w a v e fo r m s is t o s h if t t h e ef fe c t i v e v a lu e of t h e i n te rc e p t upw a rd s or d o w n w a rd s . g r a p h i c a l l y , t h i s lo oks li k e a v e r t ica l shif t in t h e log a m plif ier s t r a n sfer f u n c t i o n . the loga r i t h mic s l o p e , h o we v e r , is n o t a f fe c t e d . f o r exa m ple , co n s ider t h e cas e o f t h e ad831 2 b e i n g alt e r n a t e l y fe d b y a n unmo d u la te d si n e wa ve an d b y a 64 q a m sig n a l o f t h e s a me r m s p o w e r . the ad8312 s o u t p u t v o l t a g e dif f ers b y t h e e q ui vale n t o f 1. 6 db (31 mv) o v er t h e com p lete d y na mic ra n g e o f t h e de vice ( w i t h t h e o u t p u t fo r a 64 q a m i n p u t b e in g l o w e r ) . f i gur e 29 sh o w s th e tran sf er f u n c tio n o f t h e ad8312 when dr i v en b y b o t h a n unm o d u l a t e d si n e w a v e and s e v e ral dif f er en t sig n al wa v e f o r m s. f o r p r ecisio n o p era t io n, t h e ad8312 sh o u l d be cali b r a t ed f o r ea c h s i gn al t y pe th a t i s d r i v in g i t . t o m e as ur e t h e r m s p o w e r o f a 64 q a m i n p u t, fo r exa m ple , t h e mv eq ui valen t o f t h e db va l u e (19.4 7 mv/db 1.6 db) sh o u ld be s u b t rac t e d f r o m t h e o u t p u t v o l t a g e o f t h e a d 83 12.
ad8312 rev. 0| page 16 of 2 0 5 ?5 ?4 ?3 ?2 ?1 0 1 2 3 4 ? 6 0 ? 50 ?40 ? 30 ? 2 0 ? 10 0 10 64 qam 05260-029 input (dbm) vout (v) cw is-95 rev wcdma 64-ch f i gure 2 9 . shi f t in t r a n sfer f u ncti on d u e to sev e r a l di ffer e nt signa l w a v e fo rm s tem p er at ur e drift f i gur e 30 sh o w s t h e log s l op e and er r o r o v er t e m p era t ur e fo r a 0.9 gh z in p u t s i g n al. er r o r d u e t o dr if t o v er t e m p era t ur e co n s is t e n t l y r e ma in s wi thin 0 .5 db an d o n l y beg i n s t o excee d t h is limi t w h en t h e am b i e n t t e m p era t ur e g o es a b o v e 70c. f o r al l f r eq uen c ies usin g a r e d u ce d t e m p era t ur e ra n g e , hig h er m e as ur e m en t acc u rac y is achie v a b le . 1.3 1.0 0.8 0.5 0.3 0 2.5 ?2.5 ?2.0 ?1.5 ?1.0 ?0.5 0 0.5 1.0 1.5 2.0 ?60 ? 50 ? 4 0 ? 30 ?20 ? 10 0 1 0 05260- 030 p in (dbm) vout (v) error (db) +85 c +70 c +25 c 0 c ?1 0 c ?2 0 c ?4 0 c f i g u re 30. t y pic a l d r if t at 90 0 g h z f o r v a r i ous t e mpe r at u r es operation abov e 2.5 ghz the ad8312 wo rks a t hig h f r eq uen c ies, b u t e x h i b i t s s l i g h t l y hig h er o u t p u t v o l t a g e t e m p era t ur e dr if t. f i gur e 31 a n d fi g u r e 3 2 sh o w t h e t r a n s f e r f u nc t i ons a n d e r ror d i st r i but i ons of a l a r g e p o p u la tio n o f devices a t 3.0 gh z a nd 3.5 gh z o v er t e m p era t ur e . d u e t o t h e r e p e a t a b i l i t y o f t h e dr i f t f r o m p a r t -t o- p a r t , co m p en s a t i o n can be a p p l ied t o r e d u ce t h e ef f e c t s o f t e m p era t ur e dr i f t. i n t h e cas e o f t h e 3.5 gh z di st r i b u t i o n , an in t e r c ep t co r r e c t i o n o f 2.0 db a t 85c w o u l d i m p r o v e t h e acc u rac y o f th e dis t r i b u t i o n t o 2 db o v er a +4 0 db ra n g e . 1.0 0.8 0.6 0.4 0.2 0.9 0.7 0.5 0.3 0.1 0 5 ?5 ?4 ?3 ?2 ?1 0 1 2 3 4 ?55 ? 45 ?35 ? 25 ?15 ? 5 5 05260- 031 p in (dbm) vout (v) error (db) +85 c +25 c ?40 c f i g u re 31.o u t p ut v o lt ag e and e r r o r at ?4 0c, +2 5c , a n d +8 5c af ter a m bie n t no rm a liz at io n v s . input a m plit ude at 3.0 gh z f o r 60 d e v i ces 1.0 0.8 0.6 0.4 0.2 0.9 0.7 0.5 0.3 0.1 0 5 ?5 ?4 ?3 ?2 ?1 0 1 2 3 4 ?55 ? 45 ?35 ? 25 ?15 ? 5 5 05260- 032 p in (dbm) vout (v) error (db) +85 c +25 c ?40 c f i g u re 32. o u t p ut v o lt ag e and e r r o r at ?4 0c, +2 5c , a n d +8 5c af ter a m bie n t no rm a liz at io n v s . input a m plit ude at 3.5 gh z f o r 30 d e v i ces device h a ndli ng the wa fer - l e v e l chi p s c ale p a ckag e co n s is ts o f s o lder b u m p s co nn e c te d to t h e ac t i ve si de o f t h e die. t h e p a r t is le ad-f r e e wi t h 95.5% tin, 4.0 % sil v er , a nd 0.5% co p p er s o lder b u m p co m p - osi t io n. th e wl cs p p a cka g e c a n b e m o un t e d o n p r in te d c i r c ui t b o a r ds usin g st anda r d sur f ace - m o u n t ass e m b ly te chniq u es; h o we ver , c a u t ion sh o u ld b e t a ken to a v oid da m a g i n g t h e d i e. s e e t h e an-617 a p plic a t ion n o te fo r addi t i o n a l info r m a t io n. wlcs p de vices a r e b u m p e d di e, a nd ex p o s e d d i e can b e s e n s i t i v e to li g h t co ndi t i o n , w h i c h can inf l ue n c e sp e c if ie d li mi t s . eval uation boar d f i gur e 33 sh o w s th e s c h e ma tic of th e ad8312 e v al u a tion bo a r d. the l a yo u t an d si l k s c r e en o f t h e co m p on en t and cir c ui t sides are sh ow n i n fi g u re 3 4 to f i g u re 3 7 . t h e b o ard i s p o we re d b y a sin g le s u p p l y in th e 2.7 v t o 5.5 v ra n g e . th e p o w e r s u p p l y is deco u p led b y a sin g le 0.1 f c a p a ci t o r . t a b l e 6 de t a ils t h e v a r i o u s co nf igura t io n o p t i o n s o f t h e ev al ua t i o n boa r d .
ad8312 rev. 0| page 17 of 2 0 05260- 033 ad8312 c3 (open) v out rfin 1 comm 2 cflt 3 vpos 6 vout 5 vset 4 vset vpos input r3 0 ? r7 0 ? c2 0.1 f r1 52.3 ? r4 0 ? r6 (open) to edge connector r8 (open) c4 (open) r2 (open) to edge connector r5 (open) f i g u re 33. ev aluat i on b o a r d s c h e m a t i c 05260- 036 f i gure 34. si lks c ree n of compon ent s i de ( w l c s p ) 05260-034 f i gure 35. lay o ut of c o mpon ent sid e ( w l c sp ) 05260- 037 f i gure 36. si lks c ree n of c i rcuit s i de ( w l c sp ) 05260-035 f i gure 37. layo ut o f circuit s i de ( w l c s p )
ad8312 rev. 0| page 18 of 20 table 6. evaluation board configuration options component function default condition vpos, gnd supply and ground vector pins. not applicable c2 power supply decoupling. the nominal supply de coupling consists of a 0.1 f capacitor (c1). c2 = 0.1 f (size 0603) r1 input interface. the 52.3 ? resistor in position r1 combines with the ad8312s internal input impedance to give a broadband input impedance of around 50 ?. r1 = 52.3 ? (size 0603) r2, r4 slope adjust. by installing resistors in r2 and r4, the nominal slope of 20 mv/db can be changed. see the increasing the logarithmic slope section for more details. r2 = open (size 0402) r4 = 0 ? (size 0402) c3 filter capacitor. the response time of vout can be mo dified by placing a capacitor between cflt (pin 4) and vout (pin 2). c3 = open (size 0603) r3, r8, c4 output interface. r3, r8, and c4 can be used to chec k the response of vout to capacitive and resistive loading. r3/r8 can be used to attenuate vout. r3 = 0 ? (size 0603) r8 = c4 = open (size 0402) r7 vset interface. r7 can be used to reduce capacitive loading from transmission lines. r7 = 0 ? (size 0603) r5, r6 alternate interface. r5 and r6 allo w for vout and vset to be accessi ble from the edge connector, which is only used for characterization. r5 = r6 = open (size 0402)
ad8312 rev. 0| page 19 of 2 0 outline dimensions 0.50 bsc 1.00 bsc 1.50 1.45 1.40 1.00 0.95 0.90 seating plane 0.675 0.595 0.515 0.075 coplanarity 0.380 0.355 0.330 0.345 0.295 0.245 0.270 0.240 0.210 a1 ball corner 0.50 bsc 1 a b 2 3 top view (bump side down) bottom view (bump side up) f i gure 38. 6-b a l l w a fer - l e vel ch ip s c a l e p a ck ag e [ w l c s p ] (c b - 6) 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 ption package ou tline brand i ng information ordering quantity ad8312acbz-p 7 1 C40c to +85c 6-ball wlcsp, 7 po cket tape and reel cb-6 q00 3000 ad8312acbz-p 2 1 C40c to +85c 6-ball wlcsp, 7 po cket tape and reel cb-6 q00 250 a d 8 3 1 2 - e v a l e v a l u a t i o n boar d 1 z = pb-free part.
ad8312 rev. 0| page 20 of 2 0 notes ?2005 a n alo g d e vi ces, inc. all rights reserve d . tra d emar ks an d registered tra d emar ks are the prop erty of their respective owners . d05260C0C 4/05(0)

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