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5 v, 0.8 ma profibus rs-485 transceiver adm1486 rev. a in fo rmation furn ished by an alog d e v i c e s is believed to be accurate and reliable. how e ver, n o resp on sibili ty is assume d b y a n alog de vices fo r its use, nor for an y i n fri n geme nt s of p a t e nt s or ot h e r ri ght s o f th ird parties th at may result fro m its use . s p ecificatio n s subj ec t to ch an g e witho u t n o tice. no licen s e is g r an te d by implicati o n or ot herwi s e u n der a n y p a t e nt or p a t e nt ri ghts of analog de v i ces. trademarks an d registered tra d ema r ks are the prop erty o f their respective ow ners. one technolog y way, p.o . box 9106, norwood, ma 02062-9106, u.s.a. t e l: 781. 329. 4 700 www.analog.com fax: 781. 461. 31 13 ? 2005 analog de vices, i n c. al l r i ght s r e ser v ed . features meets and exceeds eia rs-48 5 and ei a rs-4 22 stand a rds 30 mbps data r a te recommended for profibus applications 2.1 v m i nimum different ial ou tput with 54 ? termination low power 0.8 ma i cc thermal shut d o wn and short-circuit protection 0.5 ns sk ew dri v er and receive r driver propaga t ion delay: 11 n s receiver propagation delay: 1 2 ns high impedance outputs with drivers disable d or power off superior upgrade for sn65al s 1176 avail a ble in st a n dard 8 - lea d s o ic package applic ati o ns industrial fiel d equipment general description the ad m1486 is a dif f er en t i al l i ne tra n s c ei v e r sui t a b le f o r hig h sp e e d b i dir e c t iona l d a t a co m m unica t io n on m u l t i p o i n t b u s tra n smis sio n lines. i t is desig n e d fo r bala n c e d da ta tra n smis sion, co m p lies wi t h e i a s t an da r d s rs-485 an d rs -4 22, a n d is r e com- me nd e d for pr of i b u s a p pl i c a t i o ns . t h e p a r t c o n t ai ns a dif f er en t i al l i n e dr i v er a nd a dif f er en t i a l li n e r e c e i v er . b o t h t h e dr i v er a nd t h e r e cei v er ma y b e ena b le d i n dep e n d e n t l y . w h en di s a b l e d o r p o were d dow n , t h e d r i v er outp ut s a r e h i g h i m p e d a nc e. the ad m1486 o p era t es f r o m a sin g le 5 v p o w e r s u p p l y . e x c e ss ive p o we r diss i p a t ion c a u s e d b y b u s c o n t e n t i on or ou tpu t shor t i ng i s pr e v e n te d by s h or t - c i rc u i t prote c t i o n a n d t h e r m a l cir c ui t r y . sh o r t-cir c ui t p r o t e c t i on cir c ui ts li mi t t h e maxim u m o u t p u t c u r r en t to 200 ma d u r i n g fa u l t condi t i o n s. a t h er mal s h u t do w n cir c ui t s e n s es if t h e di e t e m p era t ur e r i s e s a b o v e 150c an d f o r c es th e dr i v er o u t p u t s in t o a hig h im p e dan c e sta t e un der t h is cond i t io n. u p t o 50 tra n s c ei v e rs ma y be c o nn ec t e d sim u l t a n eo us l y on a b u s, b u t onl y o n e dr i v er s h o u l d b e enab le d a t a t i me . th er efo r e , i t is i m p o r t a n t t h a t t h e r e maini n g dis a b l e d dr i v ers do n o t lo ad th e b u s. func tio n a l block di agram adm1486 r d ro re de di v cc b a gnd 8 5 6 7 1 4 3 2 02603-001 fi g u r e 1 . t o en s u r e this, th e ad m1486 dr i v er f e a t ur es hig h o u t p u t im p e d a n c e w h e n dis a b l e d and w h en p o w e r e d do wn. t h is minimi zes t h e l o adin g ef fe c t w h e n t h e t r a n s c eiv e r is n o t b e in g us e d . t h e hi g h i m p e dance dr i v e r o u t p u t is m a in t a i n e d o v er t h e en t i r e co mmo n -mo d e v o l t a g e r a n g e f r o m ?7 v t o +12 v . the r e cei v er con t a i n s a fail-s a f e fe a t ur e t h a t r e su l t s in a log i c hig h o u t p ut s t a t e if t h e i n p u ts ar e un co nn e c t e d (f lo a t in g). the ad m1486 is fa b r ica t e d o n b i cm os, a n adva n c ed mixed t e c h n o log y p r oces s com b inin g lo w p o w e r cm os wi th fas t s w i t ch ing b i p o l a r te ch nol o g y . a l l in p u ts and out p u t s c o n t ai n prote c t i on ag ai nst e s d ; a l l d r ive r output s f e a t u r e h i g h s o u r c e a nd sin k c u r r en t ca p a b i li ty . a n ep i t ax ia l l a yer is us e d to gua r d ag ai ns t l a tc h - up . the ad m1486 f e a t ur es extr eme l y fas t and c l os e l y ma t c h e d sw i t ch in g, enab l e , a nd dis a b l e t i m e s. mi nima l d r i v er p r o p a g a - tio n de l a ys p e r m i t tran smis sion a t da t a ra t e s u p t o 30 mb ps w h i l e lo w sk e w mini mizes emi in t e r f er en c e . the p a r t is f u l l y s p e c if ie d o v er t h e comm er cial a nd i n d u s t r i al t e m p era t ur e ra ng e a nd is a v a i lab l e in an 8-le ad so i c p a cka g e .
adm1486 rev. a | page 2 of 16 table of contents specifications ..................................................................................... 3 timing specifications ....................................................................... 4 absolute maximum ratings ............................................................ 5 esd caution .................................................................................. 5 pin configuration and function descriptions ............................. 6 te s t c i rc u it s ....................................................................................... 7 switching characteristics ................................................................ 8 typical performance characteristics ............................................. 9 applications information .............................................................. 13 differential data transmission ................................................ 13 cable and data rate ................................................................... 13 thermal shutdown .................................................................... 13 propagation delay ...................................................................... 13 receiver open-circuit fail-safe ............................................... 13 outline dimensions ....................................................................... 15 ordering guide .......................................................................... 15 revision history 3/05rev. 0 to rev. a updated format..................................................................universal added profibus logo .................................................................. 1 updated outline dimensions ....................................................... 15 changes to ordering guide .......................................................... 15 11/02revision 0: initial version
adm1486 rev. a | page 3 of 16 specifications v cc = 5 v 5%. all specifications t min to t max , unless otherwise noted. table 1. parameter min typ max unit test conditions/comments driver differential output voltage, v od 5.0 v r = infinity, see figure 3 2.1 5.0 v v cc = 5 v, r = 50 ? (rs-422), see figure 3 2.1 5.0 v r = 27 ? (rs-485), see figure 3 v od3 2.1 5.0 v v tst = ?7 v to +12 v, see figure 4 ?| v od | for complementary output states 0.2 v r = 27 ? or 50 ?, see figure 3 common-mode output voltage v oc 3.0 v r = 27 ? or 50 ?, see figure 3 ?| v oc | for complementary output states 0.2 v r = 27 ? or 50 ? output short-circuit current (v out = high) 60 200 ma ?7 v v o +12 v output short-circuit current (v out = low) 60 200 ma ?7 v v o +12 v cmos input logic threshold low, v inl 0.8 v cmos input logic threshold high, v inh 2.0 v logic input current (de, di) 1.0 a receiver differential input threshold voltage, v th ?0.2 +0.2 v ?7 v v cm +12 v input voltage hysteresis, ?v th 70 mv v cm = 0 v input resistance 20 30 k? ?7 v v cm +12 v input current (a, b) 0.6 ma v in = +12 v ?0.35 ma v in = ?7 v logic enable input current ( re ) 1.0 a cmos output voltage low, v ol 0.4 v i out = +4.0 ma cmos output voltage high, v oh 4.0 v i out = ?4.0 ma short-circuit output current 7 85 ma v out = gnd or v cc three-state output leakage current 1.0 a 0.4 v v out 2.4 v power supply current i cc (outputs enabled) 1.2 2.0 ma outputs unloaded, digital inputs = gnd or v cc i cc (outputs disabled) 0.8 1.5 ma outputs unloaded, digital inputs = gnd or v cc
adm1486 rev. a | page 4 of 16 timing specifications v cc = 5 v 5%. all specifications t min to t max , unless otherwise noted. table 2. parameter min typ max unit test conditions/comments driver propagation delay input to output t plh , t phl 4 11 17 ns r ldiff = 54 ?, c l1 = c l2 = 100 pf, see figure 5 11 13 ns r ldiff = 54 ?, c l1 = c l2 = 100 pf @ t a = 25c driver o/p to o/p t skew 0.5 2 ns r ldiff = 54 ?, c l1 = c l2 = 100 pf, see figure 5 1 driver rise/fall time t r , t f 8 15 ns r ldiff = 54 ?, c l1 = c l2 = 100 pf, see figure 5 driver enable to output valid t zh , t zl 9 15 ns r l = 110 ?, c l = 50 pf, see figure 6 driver disable timing t hz , t lz 9 15 ns r l = 110 ?, c l = 50 pf, see figure 6 matched enable switching | t azh ? t bzl |, | t bzh ? t azl | 1 3 ns r l = 110 ?, c l = 50 pf, see figure 6 matched disable switching | t ahz ? t blz |, | t bhz ? t alz | 2 5 ns r l = 110 ?, c l = 50 pf, see figure 6 receiver propagation delay input to output t plh , t phl 6 12 20 ns c l = 15 pf, see figure 7 skew | t plh ? t phl | 0.4 2 ns c l = 15 pf 1 , see figure 7 receiver enable t zh , t zl 7 13 ns c l = 15 pf, r l = 1 k?, see figure 8 receiver disable t hz , t lz 7 13 ns c l = 15 pf, r l = 1 k?, see figure 8 1 guaranteed by characterization.
adm1486 r e v. a | pa ge 5 o f 1 6 absolute maximum ratings t a = 2 5 c , u n l e ss ot he r w i s e not e d. table 3. p a r a m e t e r r a t i n g v cc 7 v inputs driver input (di) ?0.3 v to v cc + 0.3 v control inputs (de, re ) ?0.3 v to v cc + 0.3 v receiver inputs (a, b) ?9 v to +14 v o u t p u t s driver outputs ?9 v to +14 v receiver outputs ?0.5 v to v cc + 0.5 v power dissi pati on 8-lead soic 450 mw ja , thermal impedance 170c/w operating tem p erature range industrial (a ver s ion) ?40c to +85c storage temperature range ?65c to +150c lead temperature (soldering, 10 sec) 300c vapor phase (60 sec) 215c infrared (15 sec) 220c s t r e s s es a b o v e t h os e lis t e d u n de r a b s o l u t e m a xi m u m r a t i n g s ma y c a us e p e r m a n en t dama ge t o t h e de vice . this is a s t r e s s r a t i ng o n ly ; f u nc t i on a l op e r a t i o n of t h e d e v i c e a t t h e s e or a n y o t h e r con d i t io ns a b o v e t h os e i ndic a t e d in t h e in t h e o p er a t io nal 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 m a xi m u m ra tin g co n d i ti o n s f o r e x t e n d ed pe ri od s o f ti m e m a y af fe c t d e v i c e rel i a b i l it y . esd caution esd (electrostatic discharge) se nsitive device. electros tatic charges as high as 4000 v readily accumulate on the human body and test eq ui pment and can discharge wi thout detection. although this product features proprietary esd protection circ uitry, permanent dama ge may occur on dev i ces subj ected to high energy electrostatic di scharge s . t h erefore, proper esd precautions are recom m ended to avoid performan c e degradation or l o ss of functiona l ity.
adm1486 r e v. a | pa ge 6 o f 1 6 pin conf iguration and fu nction descriptions ro 1 re 2 de 3 di 4 v cc 8 b 7 a 6 gnd 5 adm1486 top view (not to scale) 02603-002 f i gure 2. pin config ur ation ta ble 4. pi n f u nct i on d e s c ri pt i o ns pin o. nemonic description 1 ro receiver output. when enabled, if a > b by 200 mv, ro = high. if a < b by 200 m v , ro = low. 2 re receiver output enable. a lo w le vel ena b les the r e ceiver o utput, ro. a high level place s it in a hig h impedance state. 3 d e driver output enable. a high le vel ena b les the driver differe nti a l outputs, a and b. a low level place s it in a hig h impedance stat e. 4 d i driver input. when the driver is enabled, a logic low o n di forces a low and b hig h , while a logic high on di forces a high and b lo w. 5 gnd ground connec t ion, 0 v. 6 a noninverting receiver input a/ driver output a. 7 b inverting receiver input b/ driver output b. 8 v cc power supply, 5 v 5%. table 5. trans m itting d input di input b output a output 1 1 0 1 1 0 1 0 0 x z z table 6. receivin g r ab input ro output 0 +0.2 v 1 0 ?0.2 v 0 0 i n p u t s o p e n 1 1 x z
adm1486 r e v. a | pa ge 7 o f 1 6 test circuits 02603-003 v oc r r a b v od f i gure 3. d r iver v o l t age me asurem ent 02603-004 60 ? v od3 375 ? 375 ? v tst a b f i gure 4. d r iver v o l t age me asurem ent 02603-005 c l2 c l1 r ldiff a b f i g u re 5. d r iver p r o p ag at i o n d e l a y 02603-006 v cc r l s2 v ou t c l s1 b a 0 vo r 3 v de i n de f i g u re 6. d r iver e n abl e /d is abl e 02603-07 c l v ou t re a b f i gure 7. r eceive r pr op agati o n d e l a y 02603-008 v cc s2 v ou t r l c l +1 . 5 v ?1 . 5 v s1 re re i n f i gure 8. r eceive r e n abl e /d isab le
adm1486 r e v. a | pa ge 8 o f 1 6 switching characteristics 02603-009 t ph l t pl h 3v 0v vo b a vo 0v ? vo 1.5v 1.5v t f t r 10% point 10% point 90% point 90% point 1/2vo t skew = |t plh ? t phl | f i g u re 9. d r iver p r o p ag at i o n d e l a y , r i s e /f a ll ti mi ng 02603-010 t lz t zl t hz t zh v oh ?0.5v v ol +0.5v a, b a, b de 3v 0v 1.5v 1.5v 2.3v 2.3v v ol v oh 0v f i g u re 10. d r iver e n abl e /d is abl e ti min g 02603-011 a? b ro 0v 0v 1. 5v 1. 5v t plh t skew = |t plh ? t phl | t phl v oh v ol f i g u re 11. r e c e iver p r op ag at ion d e l a y 02603-012 3v 0v 1.5v 1.5v v oh v ol o/p low o/p high t lz t zl t hz t zh v oh ? 0.5v v ol +0.5v 1.5v 1.5v ro ro re 0v f i g u re 12. r e c e iver e n able /d is abl e ti ming
adm1486 r e v. a | pa ge 9 o f 1 6 typical perf orm ance cha r acte ristics output voltage (v) outp ut curre nt (ma) 35 30 25 20 10 15 0 5 0 0.50 0.25 1.00 0.75 1.50 1.75 1.25 2.00 02603-013 f i gure 13. o u tput current v s . r e c e ive r o u tput l o w v o lt ag e output voltage (v) outp ut curre nt (ma) 0 ?5 ?10 ?20 ?15 ?30 ?25 3.50 3.75 4.25 4.00 4.50 4.75 5.00 02603-014 f i gure 14. o u tput current v s . r e c e ive r o u tput high v o lt a g e temperature ( c) output voltage (v) 4.75 4.70 4.60 4.65 4.50 4.55 ?50 ? 25 50 25 0 7 5 100 125 02603-015 f i gure 15. r e c e iver o u tput high v o lt a g e v s . t e mper ature (i = 8 m a ) temperature ( c) output voltage (v) 0.50 0.45 0.25 0.40 0.35 0.30 0.15 0.20 ?50 ? 25 50 25 0 7 5 100 125 02603-016 f i gure 16. r e c e iver o u tput l o w v o lt ag e v s . t e mper ature (i = 8 m a ) output voltage (v) outp ut curre nt (ma) 80 70 20 60 50 30 40 ?10 0 10 0 0.5 2.5 2.0 1.5 1.0 3.5 3.0 4.0 4.5 02603-017 f i gure 17. o u tput current v s . d r iv e r d i f f er ent i a l o u tput v o ltage temperature ( c) output voltage (v) 3.00 2.95 2.75 2.90 2.80 2.85 2.60 2.65 2.70 ?50 2 5 0 ?2 5 7 5 50 100 125 02603-018 f i gure 18. d r iver d i ffer e nti a l o u tput v o ltag e v s . t e mpe r a t ur e (r ldi f f = 53 .6 ?)
adm1486 rev. a | page 10 of 16 output voltage (v) outp ut curre nt (ma) 90 70 30 60 40 50 0 10 20 0 1.5 1.0 0.5 2.5 2.0 3.5 3.0 4.0 02603-019 f i gure 19. o u tput current v s . d r ive r o u t p ut l o w v o lt ag e output voltage (v) outp ut curre nt (ma) 0 ?10 ?50 ?20 ?40 ?30 ?80 ?70 ?60 0 1.5 1.0 0.5 3.0 2.5 2.0 4.5 4.0 3.5 5.0 02603-020 f i gure 20. o u tput current v s . d r ive r o u t p ut hig h v o lt ag e temperature ( c) outp ut curre nt (ma) 1.30 1.25 1.00 1.20 1.05 1.10 1.15 0.80 0.85 0.90 0.95 ?50 ? 25 25 0 100 75 50 125 02603-021 driver enabled driver disabled f i gure 21. sup p l y current v s . t e mper at ur e temperature ( c) time (ns) 1.4 1.3 1.0 1.1 1.2 0.6 0.7 0.8 0.9 ?50 ? 25 25 0 100 75 50 125 02603-022 f i gure 22. r e c e iver sk ew v s . t e mpe r at ur e temperature ( c) time (ns) 5.0 4.5 2.5 3.0 3.5 4.0 0 0.5 1.0 1.5 2.0 ?75 ? 50 25 0 ?25 125 100 75 50 150 02603-023 |t plha ?t plhb | |t phla ?t phlb | crosspoint a, b f i gure 23. d r iver skew v s . t e mpe r atu r e temperature ( c) pw d 1.0 0.9 0.5 0.6 0.7 0.8 0 0.1 0.2 0.3 0.4 ?75 ? 50 25 0 ?25 125 100 75 50 150 02603-024 |t plh ?t phl | f i g u re 24. t x p u ls e w i dt h d i s t o r t i on
adm1486 rev. a | page 11 of 16 02603-025 ch2 ch1 1.00v ? 1.00v ? m4.00ns ch1 1.72v b a 1, 2 f i g u re 25. u n l oad e d d r ive r d i f f e r e nt ia l o u t p ut s 02603-026 ch2 ch1 500mv ? 500mv ? m4.00ns ch1 1.72v b a 1, 2 f i g u re 26. l oad ed d r iver d i f f e r e nt ia l o u t p ut (r l di ff = 54 ? , c l1 = c l2 = 10 0 pf) 02603-027 ch2 ch1 1.00v ? 1.00v ? m10.0ns ch1 1.72v b ro di a ch4 ch3 2.00v ? 5.00v ? 1, 2 4 3 f i g u re 27. d r iver/r ec e i ver pr op ag at io n d e l a y s l o w t o hi g h (r ldi f f = 54 ?, c l1 = c l2 = 100 pf) 02603-028 ch2 ch1 1.00v ? 1.00v ? m10.0ns ch1 1.72v b ro di a ch4 ch3 2.00v ? 5.00v ? 1, 2 4 3 f i g u re 28. d r iver/r ec e i ver pr op ag at io n d e l a y s h i g h t o l o w (r l di ff = 54 ? , c l1 = c l2 = 10 0 pf) 02603-029 ch2 ch1 1.00v ? 1.00v ? m10.0ns ch1 3.40v b a 1, 2 f i g u re 29. u n l oad e d d r ive r o u t p ut s at 15 m bps 02603-030 ch2 ch1 1.00v ? 1.00v ? m4.00ns ch1 3.40v b a 1, 2 f i g u re 30. u n l oad e d d r ive r o u t p ut s at 30 m bps
adm1486 rev. a | page 12 of 16 02603-031 ch2 ch1 1.00v ? 1.00v ? m4.00ns ch1 3.40v b a 1, 2 f i g u re 31. l oad ed d r iver o u t p ut s at 1 5 m bps (r ldi f f = 54 ?, c l1 = c l2 = 10 0 pf) 02603-032 ch2 ch1 1.00v ? 1.00v ? m4.00ns ch1 3.50v 1, 2 a b f i g u re 32. l oad ed d r iver o u t p ut s at 3 0 m bps (r ldi f f = 54 ?, c l1 = c l2 = 100 pf)
adm1486 rev. a | page 13 of 16 appli c ations inf ormati o n differential data tr ansmission d i f f e r e n ti al da t a tra n sm i s si o n is used t o r e lia b ly tra n sm i t d a ta a t hig h ra t e s o v er lo n g dis t an ces and t h r o ug h n o is y en v i r o nm en ts. dif f er en tial tran smis sio n n u l l if ies th e ef fe c t s o f g r o u n d s h if ts an d noi s e s i g n a l s t h a t a p p e ar a s c o m m on - m o d e volt age s on t h e lin e . th er e a r e t w o ma in st andar d s a p p r o v e d b y t h e e l e c t r o n ics i n d u s t ri e s a s so ci a t i o n (ei a ) tha t speci f y th e e l ectri c al c h a r - ac t e r i s t ics o f t r a n s c ei v e rs us e d i n dif f er en t i al da t a t r a n smis sion. the rs-422 s t anda r d s p ecif ies da ta r a t e s u p t o 10 mb a u d and lin e len g th s u p to 4,000 f e et. a sin g le dr i v er can dr i v e a tra n s- missio n li n e w i t h u p t o 10 r e ceiv ers. i n o r der to ad dr ess t r ue m u l t i p oin t comm un ic a t io n s , th e rs - 4 8 5 st anda r d w a s de f i n e d . this st anda r d me ets o r e x ce e d s a l l o f t h e r e q u ir em en ts o f rs-422, a nd i t al lo ws u p t o 32 dr i v ers a nd 32 r e cei v ers to co nn e c t to a si n g le b u s. an ex te nde d com m o n - m o d e ra n g e o f ?7 v t o +12 v is def i ne d . t h e m o st sig n if ican t dif f er en ce between t h e rs -422 a nd t h e rs -485 is tha t t h e d r i v e r s wi t h rs-485 c a n b e d i s a bl e d , a l l o w i ng more t h a n o n e d r ive r to b e co n n e c te d to a sin g le li n e ; i n fac t , 32 dr i v ers ca n b e co nne c t e d t o a s i n g le lin e . onl y o n e dr i v er s h o u ld be e n a b le d a t a tim e , b u t t h e rs-485 s t anda r d co n t a i n s addi t i o n al s p ec if ica - t i o n s t o gua r an te e de vic e s a fety in t h e e v en t o f line co n t en t i on. cable and dat a rate t w ist e d p a ir is th e tran smis sio n lin e o f ch o i ce fo r rs-485 co mm uni c a t io ns. t w iste d p a ir c a b l e t e n d s t o can c e l co m m on- m o de n o is e and ca us es c a n c e l l a t i o n o f t h e ma g n et ic f i e l ds g e n e r a t e d b y t h e c u r r en t f l o w in g t h r o ug h e a ch wir e , t h er eb y r e d u cin g t h e ef fe c t i v e i n d u c t ance o f t h e p a ir . the ad m1486 is desig n e d f o r b i dir e c t io nal da ta co m- m u nic a tion s o n m u l t i p o i n t tra n smis sio n lin e s. a typ i cal a p pl i c a t i o n s h ow i n g a m u lt ip oi n t t r ans m i s s i on ne t w or k i s s h own in f i gur e 33. an rs-485 transmis sio n lin e can ha ve as man y as 32 tra n s - cei v ers o n t h e b u s. onl y o n e dr iv er ca n t r a n s m i t a t a t i m e , b u t m u l t i p le r e ce i v e r s ma y be ena b l e d sim u l t an e o u s l y . a s wi t h an y t r an smissio n li ne , i t is im p o r t a n t to minim i z e r e f l e c t i o n s. this ca n b e achi e v e d b y t e r m ina t ing t h e ext r e m e en ds o f t h e li n e usin g r e sis t o r s e q ual t o t h e cha r ac t e r i s t ic im p e dan c e o f th e line . s t u b le ngth s o f th e main lin e sh o u ld al s o be k e p t as sh o r t as p o s s ib le . a p r o p erl y t e r m ina t e d tra n smis sio n lin e a p p e a r s p u r e l y r e sis t i v e t o t h e dr i v er . thermal shutdown the ad m1486 co n t a i n s t h er mal s h u t do wn circ ui tr y tha t p r o - t e c t s t h e p a r t f r o m exces s i v e p o w e r dis s i p a t io n d u r i n g fa u l t co n d i ti o n s. s h o r ti n g th e d r i v e r o u t p u t s t o a lo w i m pe da n c e s o ur ce ca n r e s u l t in hig h dr i v er c u r r en ts. th er mal s e n s in g cir c ui t r y det e c t s t h e i n cr e a s e i n die t e m p er a t ur e a nd dis a b l es t h e dr i v er o u t p u t s. th er mal s e n s in g cir c ui t r y is desig n e d t o dis a b l e t h e dr i v er o u t p u t s w h e n a die t e m p era t u r e r e ach e s 150c. a s t h e device co ols, the dr i v ers a r e r e -ena b l ed a t 140c. propag ation delay the ad m1486 f e a t ur es v e r y lo w p r o p a g a t ion de l a y , en s u r i n g maxim u m b a u d ra t e o p er a t ion. the w e l l - b a l a n c e d dr i v er en s u r e s dis t o r tio n -f r e e tra n smis sio n . an o t h e r im p o r t a n t sp e c if ic a t ion is a m e a s ur e of t h e sk e w b e tw e e n t h e com p le m e n t a r y o u t p uts. e x ces s i v e s k e w im p a irs t h e n o is e imm u ni ty o f t h e sys t e m an d i n cr e a s e s t h e am o u n t o f e l ectr o m a g n e ti c i n t e rf e r e n ce (emi). receiver open-circui t fa il-safe the r e cei v er i n p u t i n cl udes a f a il-s a f e fe a t ur e t h a t gu a r a n te es a log i c hig h o n t h e r e cei v er w h e n t h e i n p u ts a r e op en cir c ui t or f l o a t i ng . rt rt d r dd rr d r 02603-033 f i gure 33. t y pic a l r s -485 n e t w ork
adm1486 rev. a | page 14 of 16 table 7. comparison of rs-422, rs-4 85, and profibus interface standards specification rs-422 rs-485 profibus transmission type differential differential differential maximum cable length 4,000 ft. 4,000 ft. minimum driver output voltage 2 v 1.5 v 2.1 v driver load impedance 100 ? 54 ? 54 ? receiver input resistance 4 k? min 12 k? min 20 k? min receiver input sensitivi ty 200 mv 200 mv 200 mv receiver input voltage range ?7 v to +7 v ?7 v to +12 v ?7 v to +12 v no. of drivers/receivers per line 1/10 32/32 50/50
adm1486 rev. a | page 15 of 16 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 . 1 9 68) 4. 80 ( 0 . 1 8 90) 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) coplanarity 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 34. 8-l e ad s t anda r d s m a l l o u t l ine p a ckag e [soic ] nar r o 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 adm1486ar ?40c to +85c 8-lead narrow body (soic) r-8 adm1486ar- re el ?40c to +85c 8-lead narrow body (soic) r-8 adm1486ar- re el7 ?40c to +85c 8-lead narrow body (soic) r-8 adm1486arz 1 ?40c to +85c 8-lead narrow body (soic) r-8 adm1486arz-reel 1 ?40c to +85c 8-lead narrow body (soic) r-8 adm1486ar z -r eel7 1 ?40c to +85c 8-lead narrow body (soic) r-8 1 z = pb-free part.
adm1486 rev. a | page 16 of 16 notes ? 2005 analo g de vices, inc. all rights reserve d . tra d em arks and registered tra d ema r ks are the prop erty of their respective owners . c02603-0-3/05(a)

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