rail-to-rail upstream adsl line driver AD45048 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 dual op amp voltage fee d back wide s u pply ra nge: from 3.3 v to 24 v rail-to-rail out p ut output swing t o within 0.5 v o f supply r a ils @ 230 ma 23 v p-p differ e ntial, r load of 50 ? from 12 v supply high output current linear output current of 23 0 ma peak into 2 5 ? ?68 dbc mtpr @ 15 dbm (10 0 ? telephone line) low noise 4.5 nv/ hz volt age noise dens ity @ 100 khz 1.5 pa/ hz cur r ent noise dens ity @ 100 khz high speed 65 mhz bandw i dth (a v = 1, ? 3 db ) 55 v/s slew ra te (r load = 2 5 ? ) applic a t io ns consumer xds l modems twisted pair li ne drivers adsl cpe applications (drop in replacement for ts61 3id and el151 9cs) audio applicati o ns gener a l description the AD45048 ads l cp e lin e dr i v er is a d u al o p era t io nal a m p l if ier c a p a b l e o f dr i v in g hig h o u t p u t c u r r en t (230 ma) and f e a t ur es a ra il -to-ra il o u t p u t s t ag e tha t s w in gs to wi thin 0.5 v of th e su p p l y ra ils. the AD45048 ra il-t o-rail o u t p u t s t a g e s u r p as s e s t h e output vo lt a g e c a p a bi l i t y of t y pi c a l e m itt e r - f o l l owe r output st a g es and c a n deli ver u p to 23 v p-p dif f er en t i a l ly f r o m a sin g le 1 2 v su p p ly in a d s l c p e l i ne dr iv i n g a p pl i c a t ions . t h e l o w disto r t i o n , hig h o u t p ut c u r r en t, a nd wide o u t p ut d y namic r a n g e mak e the ad45 048 ideal f o r dr i v in g u p s t r e a m s i g n als in ads l cp e a p plica t io ns. f a b r i c a t ed wi th a d i s hi gh s p ee d x f c b - h v (ex t ra f a s t c o m p lemen t a r y bi p o la r - h i g h v o l t a g e) p r o c ess, t h e hig h ba ndwid th and fas t s l ew ra t e o f th e AD45048 k e ep dis t o r tio n t o a minim u m w h i l e dis s i p a t in g minim u m p o w e r . the AD45048 is a v a i la b l e i n a s t a nda rd 8-le ad s o i c p a cka g e t h a t c a n o p era t e f r o m ?40c t o +85c. pin c o nfig ur a t ion out1 1 ?in1 2 +in1 3 ?v s 4 +v s out2 ?in2 +in2 8 7 6 5 04817-s p0-001 f i g u re 1. 8-l e ad so ic 10 ?90 ?80 ?70 ?60 ?50 ?40 ?30 ?20 ?10 0 center 86.31174378khz 1khz/ span 10khz 04817-s p0-002 dbm ?68db f i g u re 2. a d 45 04 8 a r u p s t r e am a d sl m t pr ( 13 d b m, cf = 5. 3)
AD45048 rev. 0 | page 2 of 8 table of contents specifications ..................................................................................... 3 absolute maximum ratings ............................................................ 4 esd caution .................................................................................. 4 typical performance characteristics ............................................. 5 general description ......................................................................... 7 power supply and decoupling .................................................... 7 layout considerations ..................................................................7 cpe adsl application .................................................................7 transformer s election ..................................................................7 receive channel considerations .................................................7 outline dimensions ..........................................................................8 ordering guide .............................................................................8 revision history 7/04revision 0: initial version
AD45048 rev. 0 | page 3 of 8 specifications v s = 6 v or 12 v (@ t a = 25 c, g = +10, r l = 100 ?, unless otherwise noted). table 1. parameter test conditions/comments min typ max unit dynamic performance ?3 db bandwidth g = +1, v out = 0.1 v p-p, r fb = 0 ?, r load = 25 ? 65 mhz 0.1 db flatness v out = 0.1 v p-p single-ended, g = +1, r load = 25 ? 3.35 mhz large signal bandwidth v out = 1 v p-p single-ended, g = +10, r load = 25 ? 4.5 mhz large signal slew rate v out = 5 v p-p, g = +1, r load = 25 ? 55 v/s noise/distortion performance distortion (worst harmonic) f c = 40 khz, v out = 6 v p-p, single-ended, r load = 25 ? ?80 dbc multitone power ratio 26 khz to 134 khz, z line = 100 ?, xfmr = 1:2 turns, p line = 13 dbm ?68 dbc input voltage noise f = 100 khz 4.5 nv/hz input current noise f = 100 khz 1.5 pa/hz dc performance input offset voltage 1 2.5 mv t min ? t max 2.5 mv input offset voltage match 1 2.0 mv input bias current 200 900 na t min ? t max 1.3 a input offset current 50 300 na open-loop gain 85 94 db input characteristics input resistance f = 100 khz 87 k? input capacitance 1.4 pf output characteristics output resistance 1.4 mhz; g = +1 0.2 ? output voltage swing maximum swing (differential) v omax , r load = 50 ? differential +11.25 +11.5 v diff minimum swing (differential) v omin , r load = 50 ? differential ?11.5 ?11.25 v diff differential output voltage swing ?v out = v omax ? v omin 22.5 23 v p-p single-ended +swing r load = 25 ? +5.68 +5.76 v p single-ended -swing r load = 25 ? ?5.67 ?5.58 v p single-ended +swing r load = 100 ? +5.92 +5.95 v p single-ended Cswing r load = 100 ? ?5.91 ?5.86 v p operating range (dual supply) 1.5 12.6 v supply current 7 9 12 ma power supply rejection ratio 0.5 v ?85 ?75 db common-mode rejection ra tio 1 v ?86 ?79 db
AD45048 rev. 0 | page 4 of 8 absolute maximum ra tings table 2. p a r a m e t e r r a t i n g supply voltage 26.4 v power dissi pati on ( t jmax C t a )/ ja 1 storage temperature ?65c to +125c operating temperature range ?40c to +85c lead temperature range (sol dering 10 s e c) 300c junction tempe r ature 150c s t r e s s es a b o v e t h os e lis t e d u n de r a b s o l u t e m a xi m u m r a t i n g s ma y c a us e p e r m a n en t dama ge t o t h e de vice . this is a s t r e s s 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 . 1 ja = 112.7c/ w for soic package in st ill air based on 2s2p jedec pcb. esd c a ution esd (electrostatic discharge) sensitive device. ele c tr ostatic charg e s as high as 4000 v readily accumulate on the human body and test eq uipment and can discharg e wit h out detection. althou gh this product features proprietary esd protection circu i try, permanent damage may occur on devices s u bjec ted to high energy elec- trostatic dischar g es. t h erefore, proper esd prec aution s are reco mmended to avoid performanc e degradation or los s of functionality.
AD45048 rev. 0 | page 5 of 8 typical perf orm ance cha r acte ristics 25 ?25 ?5 ?10 ?15 ?20 0 5 10 15 20 10k 100k 1m 10m 1g 100m 04817-s p0-017 gain ( d b) frequency (hz) g = +10 g = +5 g = +2 g = +1 ? + 499 ? 25 ? r g f i gure 3. n o n i n v e r t i ng s m all sign al b a ndwidth (v s = 6 v , v o = 0. 1 v p - p , r l = 2 5 ?) 25 ?25 ?20 ?15 ?10 ?5 0 5 10 15 20 10k 100k 1m 10m 100m 1g 04817-s p0-025 gain ( d b) frequency (hz) g = ? 10 g = ? 5 g = ? 2 g = ? 1 ? + 5k ? 25 ? r g f i gure 4 . in v e r t i n g sm all si gn al ba nd wi dth (v s = 6 v , v o = 0. 1 v p - p , r l = 2 5 ?) ?40 ?80 ?70 ?60 ?50 0 5 10 15 20 04817-s p0-027 mtp r dbm (100 ? ) f i gure 5. mt pr v s . line p o wer ( s ee s c h e m a tic in f i gu r e 8) 25 ?25 ?20 ?15 ?10 ?5 0 5 10 15 20 10k 100k 1m 10m 100m 1g 04817-s p0-026 gain ( d b) frequency (hz) g = +10 g = +5 g = +2 g = +1 ? + 499 ? 25 ? r g f i gure 6. n o n i n v e r t i ng lar g e s i gn al bandwidth (v s = 6 v , v o = 1 v p - p , r l = 2 5 ?) 25 ?25 ?20 ?15 ?10 ?5 0 5 10 15 20 10k 100k 1m 10m 100m 1g 04817-s p0-018 gain ( d b) frequency (hz) g = ? 10 g = ? 5 g = ? 2 g = ? 1 ? + 5k ? 25 ? r g f i gure 7. in ve r t ing lar g e sign al band width (v s = 6 v , v o = 1 v p - p , r l = 2 5 ?) 04817-s p0-014 1 out +v in u1a AD45048 8 v+ +12v 2 3 r1 499 ? r2 3k ? r3 12.5 ? 7 out ?v in u1b AD45048 4 v? 5 6 r4 499 ? r5 3k ? r6 12.5 ? tx1 1:2 r3 100 ? +6v 0.1 f 4.7 f tant f i gure 8 . d i ffer e ntia l t e st cir c u i t for m t p r
AD45048 rev. 0 | page 6 of 8 100 1 10 10 100 1k 10k 100k 1m 10m 100m 04817-s p0-019 volta g e n o ise ( n v/ h z ) frequency (hz) f i g u re 9. v o lt ag e n o is e v s . f r equ e nc y , v s = 6 v 0 ? 120 ? 100 ?80 ?60 ?40 ?20 135 79 2468 1 0 04817-s p0-028 distortion ( d bc) output voltage (p-p) 1 1 second third f i gure 10. sing le -ended har m onic d i stor tion, v s = 6 v dc , g = +6 , r f = 49 9 ? , r g = 10 0 ?, r l = 2 5 ?, f u n d am enta l f r equ e n c y = 4 0 k h z 04817-s p0-029 2v/div m 5.00 s f i g u re 11. d i s c r e t e m u lt it one m o du lat i on o v e r dr ive r ecover y (s ee s c h e mati c in f i gure 8) 100 1 10 10 100 1k 10k 100k 1m 10m 04817-s p0-020 curre nt nois e (pa/ hz) frequency (hz) f i gure 12. input cu rr e n t no is e v s . f r eq uenc y , v s = 6 v 1000 0.001 0.01 0.1 1 10 100 10k 100k 1m 10m 100m 04817-s p0-030 outp ut imde dance ( ? ) frequency (hz) f i gure 13. o u tput imped a nce v s . f r eq uenc y 04817-s p0-031 50mv/div m 100ns f i g u re 14. sm a ll s i g n al p u ls e r e s p ons e r lo a d = 1 k?, r fb = 50 0 ?
AD45048 rev. 0 | page 7 of 8 general description the AD45048 is a voltage feedback, rail-to-rail output amplifier with high output current capability. fabricated on analog devices proprietary high speed, extra fast complementary bipolar high voltage process (x fcb-hv), the high bandwidth and fast slew rate of the AD45048 keep distortion to a mini- mum while dissipating minimum power. the xfcb-hv, silicon on insulator (soi) process prevents latch-up problems and en- ables the construction of high frequency, low distortion amplifiers, such as the AD45048. power supply and decoupling the AD45048 can be powered with a good quality, well regulated, low noise supply anywhere in the range from +3 v to 12.6 v. in order to optimize the AD45048 in standard adsl cpe line driver applications (see figure 8), power the amplifier with a well regulated 12 v supply. careful attention should be paid to decoupling the power supply. high quality capacitors with low equivalent series resistance (esr), such as multilayer ceramic capacitors (mlccs), should be used to minimize the supply voltage ripple and power dissipation. a 0.1 f mlcc decoupling capacitor(s) should be located no more than 1/8-inch away from the power supply pin(s). a large, usually tantalum, 10 f to 47 f capacitor is recommended to provide good decoupling for lower frequency signals and to supply current for fast, large signal changes at the AD45048 outputs. layout considerations as is the case with all high speed applications, careful attention to printed circuit board layout details prevent associated board parasitics from becoming problematic. proper rf layout and printed circuit board design techniques are strongly recom- mended. the pcb should have a low impedance return path (or ground) to the supply. removing the ground plane from all layers in the immediate area of the amplifier reduces stray capacitances. the signal routing should be short and direct in order to minimize the parasitic inductance and capacitance associated with these traces. termination resistors and loads should be located as close as possible to their respective inputs and outputs. input traces should be kept as far apart as possible from the output traces to minimize coupling (crosstalk) though the board. wherever there are complementary signals, a symmetrical layout should be provided to the extent possible in order to maximize balanced performance. when running differential signals over a long distance, the traces on the pcb should be close together or any differential wiring should be twisted together to minimize the area of the loop that is formed. this reduces the radiated energy and makes the circuit less susceptible to rf interference. adherence to stripline design techniques for long signal traces (greater than about 1 inch) is recommended. cpe adsl application the low cost, high output current dual AD45048 xdsl line driver amplifiers have been specifically designed to drive high fidelity xdsl signals to within 0.5 v of the power rails on a single 12 v supply. the AD45048 may be used in transformer- coupled bridge hybrid circuits designed to drive modulated signals, including discrete multitone (dmt), upstream to the central office. transformer selection customer premise adsl applications require the transmission of a 13 dbm dmt signal (20 mw into 100 ?). dmt signals can have a crest factor (v peak/v rms ratio) as high as 5.3, requiring the line driver to provide peak power of 560 mw. the line driver is required to drive a 7.5 v peak onto the 100 ? tele- phone line while maintaining about ?65 dbc to ?70 dbc of mtpr. since the maximum, low distortion output swing avail- able from the AD45048 line driver is approximately 11.5 v on a 12 v supply (depending on the load), and taking into account the power lost in the transformer and termination resistors, a step-up transformer with a minimum turns ratio of 1.5 or greater is needed. in the simplified differential driver circuit shown in figure 8, the AD45048 is driving a 25 ? impedance reflected by 1:2 step-up transformer. r3 and r6 are 12.5 ? each and are back-termination or load-matching resistors whose values can be calculated by (100 ?/(n 2 ))/2 where 100 ? is the approximate phone line impedance and n is the transformer turns ratio. in figure 8, the total differential load including the termination resistors is 50 ?, and under these conditions, the AD45048 is capable of driving low distortion signals to within 0.5 v of the power rails. receive channel considerations a step-up transformer of n turns used at the output of the differential line driver increases the differential output voltage to the line (see figure 8). however, the inverse effect is seen in the receive channel as the amplitude of signal on the driver side of the transformer is divided by n turns. the decision to use a particular transformer turns ratio may be impacted by the ability of the receive circuitry to resolve low level signals in the noisy twisted pair telephone plant. higher turns ratio trans- formers reduce the effective receive channel snr (signal-to- noise ratio) due to the reduction in the received signal strength. an amplifier with low rti noise, such as the ad8022 (2.5 nv/hz), is recommended for the receive channel. for a complete selection of amplifiers and other related components, see www.analog.com .
AD45048 rev. 0 | page 8 of 8 outline dimensions 0.25 (0.0098) 0.17 (0.0067) 1.27 (0.0500) 0.40 (0.0157) 0.50 (0.0196) 0.25 (0.0099) 45 8 0 1.75 (0.0688) 1.35 (0.0532) seating plane 0.25 (0.0098) 0.10 (0.0040) 4 1 85 5. 00 ( 0 . 196 8) 4. 80 ( 0 . 189 0) 4.00 (0.1574) 3.80 (0.1497) 1.27 (0.0500) bsc 6.20 (0.2440) 5.80 (0.2284) 0.51 (0.0201) 0.31 (0.0122) coplanarit y 0.10 controlling dimensions are in millimeters; inch dimensions (in parentheses) are rounded-off millimeter equivalents for reference only and are not appropriate for use in design compliant to jedec standards ms-012aa f i g u re 15. 8-l e ad s t anda r d s m a l l o u t l ine p a ckag e [soic ] narro w b o dy (r -8) di me nsio ns sho w n i n mi ll im e t e r s a n d (i nc he s) ordering guide model temperature r a nge package descri ption package option AD45048ar ?40c to +85c 8-lead standard small outline package (soic) r-8 AD45048ar-ree l ?40c to +85c 8-lead stan dard small outline package (soic) r-8 AD45048ar-ree l 7 ?40c to +85c 8-lead stan dard small outline package (soic) r-8 ? 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 . d04817C0C 7/04(0)
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