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3.3 v slew rate limited, half- and full-duplex, rs-485/rs-422 transceivers data sheet adm3483/adm3485/adm3488/adm3490/adm3491 rev. e information furnished by analog devices is believed to be accurate and reliable. however, no responsibility is assumed by analog devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. specifications subject to change without notice. no license is granted by implication or otherwise under any patent or patent rights of analog devices. trademarks and registered trademarks are the property of their respective owners. one technology way, p.o. box 9106, norwood, ma 02062-9106, u.s.a. tel: 781.329.4700 www.analog.com fax: 781.461.3113 ?2005-2011 analog devices, inc. all rights reserved. features operate with 3.3 v supply interoperable with 5 v logic eia rs-422 and rs-485 compliant over full common-mode range data rate options adm3483/adm3488: 250 kbps adm3485/adm3490/adm3491: 10 mbps half- and full-duplex options reduced slew rates for low emi (adm3483 and adm3488) 2 na supply current in shutdown mode (adm3483/adm3485/adm3491) up to 32 transceivers on the bus ?7 v to +12 v bus common-mode range specified over the C40c to +85c temperature range 8 ns skew (adm3485/adm3490/adm3491) 8-lead soic and 14-lead soic (adm3491 only) packages applications low power rs-485/rs-422 applications telecom industrial process control hvac general description the adm3483/adm3485/adm3488/adm3490/adm3491 are low power, differential line transceivers designed to operate using a single 3.3 v power supply. low power consumption, coupled with a shutdown mode, makes the adm3483/adm3485/adm3488/ adm3490/adm3491 ideal for power-sensitive applications. the adm3488/adm3490/adm3491 feature full-duplex com- munication, while the adm3483/adm3485 are designed for half-duplex communication. functional block diagrams r d ro v cc re di de adm3483/ adm3485 a gnd b 05524-027 figure 1. r d ro di adm3488/ adm3490 a b z y 05524-026 v cc gnd figure 2. r d ro re di de adm3491 a b z y 05524-025 figure 3. the adm3483/adm3488 feature slew rate limited drivers that minimize emi and reduce reflections caused by improperly ter- minated cables, allowing error-free data transmission at data rates up to 250 kbps. the adm3485/adm3490/adm3491 transmit at up to 10 mbps. the receiver input impedance is 12 k, allowing up to 32 trans- ceivers to be connected on the bus. a thermal shutdown circuit prevents excessive power dissipation caused by bus contention or by output shorting. if a significant temperature increase is detected in the internal driver circuitry during fault conditions, then the thermal shutdown circuit forces the driver output into a high impedance state. if the inputs are unconnected (floating), the receiver contains a fail-safe feature that results in a logic high output state. the parts are fully specified over the commercial and industrial temperature ranges. the adm3483/adm3485/ adm3488/adm3490 are available in 8-lead soic_n; the adm3491 is available in a 14-lead soic_n.
adm3483/adm3485/adm 3488/adm3490/adm3491 data sheet rev. e | page 2 of 20 table of contents features .............................................................................................. 1 ? applications....................................................................................... 1 ? general description ......................................................................... 1 ? functional block diagrams............................................................. 1 ? revision history ............................................................................... 2 ? specifications..................................................................................... 4 ? timing specificationsadm3485/adm3490/adm3491.... 5 ? timing specificationsadm3483/adm3488........................ 5 ? timing specifications adm3483/adm3485/adm3488/adm3490/adm3491 ...... 6 ? absolute maximum ratings............................................................ 7 ? esd caution.................................................................................. 7 ? pin configurations and function descriptions ........................... 8 ? typical performance characteristics ............................................. 9 ? test circuits..................................................................................... 11 ? switching characteristics .............................................................. 13 ? circuit description......................................................................... 14 ? devices with receiver/driver enables (adm3483/adm3485/adm3491)......................................... 14 ? devices without receiver/driver enables adm3488/adm3490................................................................ 14 ? reduced emi and reflections (adm3483/adm3488) ....... 14 ? low power shutdown mode (adm3483/adm3485/adm3491)......................................... 14 ? driver output protection.......................................................... 14 ? propagation delay ...................................................................... 14 ? typical applications................................................................... 14 ? line length vs. data rate ......................................................... 15 ? outline dimensions ....................................................................... 17 ? ordering guide .......................................................................... 18 ? revision history 11/11rev. d to rev. e changes to digital i/o voltage (de, re , di) parameter, table 6 ................................................................................................ 7 moved typical performance characteristics section .................. 9 moved test circuits section.......................................................... 11 moved switching characteristics section ................................... 13 changes to note 1, table 8 ............................................................ 14 changes to outline dimensions................................................... 17 12/10rev. c to rev. d changes to figure 33...................................................................... 15 8/10rev. b to rev. c changes to table 2, driver input logic......................................... 4 10/06rev. a to rev. b updated format..................................................................universal added adm3491 ...............................................................universal changes to specifications section...................................................4 changes to typical applications section .................................... 14 7/06rev. 0 to rev. a changes to applications ...................................................................1 changes to general description .....................................................1 changes to figure 19...................................................................... 10 changes to typical applications section .................................... 13 changes to figure 31 and figure 32............................................. 14 updated outline dimensions....................................................... 15 10/05revision 0: initial version
data sheet adm3483/adm3485/adm 3488/adm3490/adm3491 rev. e | page 3 of 20 table 1. adm34xx part comparison part no. guaranteed data rate (mbps) supply voltage (v) half-/full- duplex slew rate limited driver/receiver enable shutdown current (na) pin count adm3483 0.25 3.0 to 3.6 half yes yes 2 8 adm3485 10 3.0 to 3.6 half no yes 2 8 adm3488 0.25 3.0 to 3.6 full yes no n/a 8 adm3490 10 3.0 to 3.6 full no no n/a 8 adm3491 10 3.0 to 3.6 full no yes 2 14
adm3483/adm3485/adm 3488/adm3490/adm3491 data sheet rev. e | page 4 of 20 specifications v cc = 3.3 v 0.3 v, t a = t min to t max , unless otherwise noted. table 2. parameter min typ max unit test conditions/comments driver differential output voltage (v od ) 2.0 v r l = 100 (rs-422), v cc = 3.3 v 5% (see figure 17 ) 1.5 v r l = 54 (rs-485) (see figure 17 ) 1.5 v r l = 60 (rs-485), v cc = 3.3 v (see figure 18 ) |v od | for complementary output states 1 0.2 v r l = 54 or 100 (see figure 17 ) common-mode output voltage (v oc ) 3 v r l = 54 or 100 (see figure 17 ) |v oc | for common-mode output voltage 1 0.2 v r l = 54 or 100 (see figure 17 ) driver input logic cmos input logic threshold low (v il ) 0.8 v de, di, re cmos input logic threshold high (v ih ) 2.0 v de, di, re cmos logic input current (i in1 ) 2 a de, di, re 1.0 ma v in = 12 v, de = 0 v, v cc = 0 v or 3.6 v input currenta, b (i in2 ) ?0.8 ma v in = ?7 v, de = 0 v, v cc = 0 v or 3.6 v 0.1 a v in = 12 v, de = 0 v, re = 0 v, v cc = 0 v or 3.6 v, adm3491 only output leakagey, z (i o ) ?0.1 a v in = ?7 v, de = 0 v, re = 0 v, v cc = 0 v or 3.6 v, adm3491 only 0.01 a v in = 12 v, de = 0 v, re = v cc , v cc = 0 v or 3.6 v, adm3491 only output leakage (y, z) in shutdown mode (i o ) ?0.01 a v in = ?7 v, de = 0 v, re = v cc , v cc = 0 v or 3.6 v, adm3491 only receiver differential input threshold voltage (v th ) ?0.2 +0.2 v ?7 v < v cm < +12 v input hysteresis ( v th ) 50 mv v cm = 0 v cmos output voltage high (v oh ) v cc C 0.4 v i out = ?1.5 ma, v id = 200 mv (see figure 19 ) cmos output voltage low (v ol ) 0.4 v i out = 2.5 ma, v id = 200 mv (see figure 19 ) three-state output leakage current (i ozr ) 1 a v cc = 3.6 v, 0 v v out v cc input resistance (r in ) 12 k ?7 v < v cm < +12 v power supply current 1.1 2.2 ma de = v cc , re = 0 v or v cc , no load, di = 0 v or v cc supply current (i cc ) 0.95 1.9 ma de = 0 v, re = 0 v, no load, di = 0 v or v cc supply current in shutdown mode (i shdn ) 0.002 1 a de = 0 v, re = v cc , di = v cc or 0 v ?250 ma v out = ?7 v driver short-circuit output current (i osd ) 250 ma v out = 12 v receiver short-circuit output current (i osr ) 8 60 ma 0 v < v ro < v cc 1 ? v od and ? v oc are the changes in v od and v oc , respectively, when di input changes state.
data sheet adm3483/adm3485/adm 3488/adm3490/adm3491 rev. e | page 5 of 20 timing specifications adm3485/adm3490/adm3491 v cc = 3.3 v, t a = 25c, unless otherwise noted. table 3. parameter min typ max unit test conditions/comments driver differential output delay (t dd ) 1 22 35 ns r l = 60 ( see figure 20 and figure 26 ) differential output transition time (t td ) 3 8 25 ns r l = 60 ( see figure 20 and figure 26 ) propagation delay, low-to-high level (t plh ) 7 22 35 ns r l = 27 ( see figure 21 and figure 27 ) propagation delay, high-to-low level (t phl ) 7 22 35 ns r l = 27 ( see figure 21 and figure 27 ) |t plh C t phl | propagation delay skew 1 (t pds ) 8 ns r l = 27 ( see figure 21 and figure 27 ) driver output enable/di sable times (adm3485/ adm3491 only) output enable time to low level (t pzl ) 45 90 ns r l = 110 ( see figure 23 and figure 29 ) output enable time to high level (t pzh ) 45 90 ns r l = 110 ( see figure 22 and figure 28 ) output disable time from high level (t phz ) 40 80 ns r l = 110 ( see figure 22 and figure 28 ) output disable time from low level (t plz ) 40 80 ns r l = 110 ( see figure 23 and figure 29 ) output enable time from shutdown to low level (t psl ) 650 900 ns r l = 110 ( see figure 23 and figure 29 ) output enable time from shutdown to high level (t psh ) 650 900 ns r l = 110 ( see figure 22 and figure 28 ) 1 measured on |t plh (y) ? t phl (y)| and |t plh (z) ? t phl (z)|. timing specificationsadm3483/adm3488 v cc = 3.3 v, t a = 25c, unless otherwise noted. table 4. parameter min typ max unit test conditions/comments driver differential output delay (t dd ) 600 900 1400 ns r l = 60 ( see figure 20 and figure 26 ) differential output transition time (t td ) 400 700 1200 ns r l = 60 ( see figure 20 and figure 26 ) propagation delay, low-to-high level (t plh ) 700 1000 1500 ns r l = 27 ( see figure 21 and figure 27 ) propagation delay, high-to-low level (t phl ) 700 1000 1500 ns r l = 27 ( see figure 21 and figure 27 ) |t plh C t phl | propagation delay skew 1 (t pds ) 100 ns r l = 27 ( see figure 21 and figure 27 ) driver output enable/disable times (adm3483 only) output enable time to low level (t pzl ) 900 1300 ns r l = 110 ( see figure 23 and figure 29 ) output enable time to high level (t pzh ) 600 800 ns r l = 110 ( see figure 22 and figure 28 ) output disable time from high level (t phz ) 50 80 ns r l = 110 ( see figure 22 and figure 28 ) output disable time from low level (t plz ) 50 80 ns r l = 110 ( see figure 23 and figure 29 ) output enable time from shutdown to low level (t psl ) 1.9 2.7 s r l = 110 ( see figure 23 and figure 29 ) output enable time from shutdown to high level (t psh ) 2.2 3.0 s r l = 110 ( see figure 22 and figure 28 ) 1 measured on |t plh (y) ? t phl (y)| and |t plh (z) ? t phl (z)|.
adm3483/adm3485/adm 3488/adm3490/adm3491 data sheet rev. e | page 6 of 20 timing specificationsadm348 3/adm3485/adm3488/adm3490/adm3491 v cc = 3.3 v, t a = 25c, unless otherwise noted. table 5. parameter min typ max unit test conditions/comments receiver time to shutdown (t shdn ) adm3483/adm3485/adm3491 1 80 190 300 ns propagation delay, low-to-high level (t rplh ) adm3485/adm3490/adm3491 25 65 90 ns v id = 0 v to 3.0 v, c l = 15 pf (see figure 24 and figure 30 ) adm3483/adm3488 25 75 120 ns propagation delay, high-to-low level (t rphl ) adm3485/adm3490/adm3491 25 65 90 ns v id = 0 v to 3.0 v, c l = 15 pf (see figure 24 and figure 30 ) adm3483/adm3488 25 75 120 ns |t plh C t phl | propagation delay skew (t rpds ) adm3485/adm3490/adm3491 10 ns v id = 0 v to 3.0 v, c l = 15 pf (see figure 24 and figure 30 ) adm3483/adm3488 20 ns receiver output enable/disable times (adm3483/adm3485/adm3491 only) output enable time to low level (t przl ) 25 50 ns c l = 15 pf (see figure 25 and figure 31 ) output enable time to high level (t przh ) 25 50 ns c l = 15 pf (see figure 25 and figure 31 ) output disable time from high level (t prhz ) 25 45 ns c l = 15 pf (see figure 25 and figure 31 ) output disable time from low level (t prlz ) 25 45 ns c l = 15 pf (see figure 25 and figure 31 ) output enable time from shutdown to low level (t prsl ) 720 1400 ns c l = 15 pf (see figure 25 and figure 31 ) output enable time from shutdown to high level (t prsh ) 720 1400 ns c l = 15 pf (see figure 25 and figure 31 ) 1 the transceivers are put into shutdown by bringing the re high and de low. if the inputs are in this state for less than 80 ns, the parts are guaranteed not to enter shutdown. if the parts are in this state for 300 ns or more , the parts are guaranteed to enter shutdown.
data sheet adm3483/adm3485/adm 3488/adm3490/adm3491 rev. e | page 7 of 20 absolute maximum ratings t a = 25c, unless otherwise noted. table 6. parameter rating v cc to gnd 7 v digital i/o voltage (de, re , di) ?0.3 v to +6 v digital i/o voltage (ro) v cc ? 0.5 v to v cc + 0.5 v driver output/receiver input voltage ?7.5 v to +12.5 v operating temperature range ?40c to +85c storage temperature range ?65c to +125c ja thermal impedance 8-lead soic 121c/w 14-lead soic 86c/w lead temperature soldering (10 sec) 300c vapor phase (60 sec) 215c infrared (15 sec) 220c stresses above those listed under absolute maximum ratings may cause permanent damage to the device. this is a stress rating only; functional operation of the device at these or any other conditions above those indicated in the operational section of this specification is not implied. exposure to absolute maximum rating conditions for extended periods may affect device reliability. esd caution
adm3483/adm3485/adm 3488/adm3490/adm3491 data sheet rev. e | page 8 of 20 pin configurations and function descriptions ro 1 re 2 de 3 di 4 v cc 8 b 7 a 6 gnd 5 adm3483/ adm3485 top view (not to scale) 05524-028 figure 4. adm3483/adm3485 pin configuration v cc 1 ro 2 di 3 g nd 4 a 8 b 7 z 6 y 5 adm3488/ adm3490 top view (not to scale) 05524-029 figure 5. adm3488/adm3490 pin configuration nc 1 ro 2 re 3 de 4 v cc 14 v cc 13 a 12 b 11 di 5 z 10 gnd 6 y 9 gnd 7 nc 8 nc = no connect adm3491 top view (not to scale) 05524-030 figure 6. adm3491 pin configuration table 7. pin function descriptions adm3483/ adm3485 pin o. adm3488/ adm3490 pin o. adm3491 pin o. mnemonic description 1 2 2 ro receiver output. when enabled, if a > b by 200 mv, then ro = high. if a < b by 200 mv, then ro = low. 2 not applicable 3 re receiver output enable. a low level enables the receiver output, ro. a high level places it in a high impedance state. if re is high and de is low, the device enters a low power shutdown mode. 3 not applicable 4 de driver output enable. a high level enables the driver differential output a and output b. a low level places it in a high impedance state. if re is high and de is low, the device enters a low power shutdown mode. 4 3 5 di driver input. with a half-duplex part when the driver is enabled, a logic low on di forces a low and b high while a logic high on di forces a high and b low. with a full-duplex part when the driver is enabled, a logic low on di forces y low and z high while a logic high on di forces y high and z low. 5 4 6, 7 gnd ground. not applicable 5 9 y noninverting driver output. not applicable 6 10 z inverting driver output. 6 not applicable not applicable a noninverting re ceiver input a and noninverting driver output a. not applicable 8 12 a noninverting receiver input a. 7 not applicable not applicable b inverting re ceiver input b and inverted driver output b. not applicable 7 11 b inverting receiver input b. 8 1 13, 14 v cc power supply (3.3 v 0.3 v). not applicable not applicab le 1, 8 nc no connect.
data sheet adm3483/adm3485/adm 3488/adm3490/adm3491 rev. e | page 9 of 20 typical performance characteristics 30 0 03 05524-012 output voltage (v) output current (ma) . 5 25 20 15 10 5 0.51.01.52.02.53.0 figure 7. output current vs. receiver output low voltage ? 16 0 03 05524-013 output voltage (v) output current (ma) . 5 ?14 ?12 ?10 ?8 ?6 ?4 ?2 0.51.01.52.02.53.0 figure 8. output current vs. receiver output high voltage 3.30 3.00 ?40 05524-014 temperature (c) output voltage (v) 3.25 3.20 3.15 3.10 3.05 ?30 ?20 ?10 0 10 20 30 40 50 60 70 80 figure 9. receiver output high voltage vs. temperature, i ro = 1.5 ma 0.8 0 ?40 05524-015 temperature (c) output voltage (v) ?30 ?20 ?10 0 10 20 30 40 50 60 70 80 0.7 0.6 0.5 0.4 0.3 0.2 0.1 figure 10. receiver output low voltage vs. temperature, i ro = 2.5 ma 100 0 03 05524-016 output voltage (v) output current (ma) . 5 90 80 70 60 50 40 30 20 10 0.51.01.52.02.53.0 figure 11. driver output current vs. differential output voltage 2.6 1.6 ?40 05524-017 temperature (c) output voltage (v) ?30 ?20 ?10 0 10 20 30 40 50 60 70 80 2.5 2.4 2.3 2.2 2.1 2.0 1.9 1.8 1.7 figure 12. driver differential output voltage vs. temperature, r l = 54
adm3483/adm3485/adm 3488/adm3490/adm3491 data sheet rev. e | page 10 of 20 140 0 01 05524-018 output voltage (v) output current (ma) 2 120 100 80 60 40 20 246810 figure 13. output current vs . driver output low voltage ? 125 ?5 ?7 3 05524-019 output voltage (v) output current (ma) ?115 ?105 ?95 ?85 ?75 ?65 ?55 ?45 ?35 ?25 ?15 ?6 ?5 ?4 ?3 ?2 ?1 0 1 2 figure 14. output current vs. driver output high voltage 1.2 0.3 ?40 05524-020 temperature (c) supply current (ma) ?30 ?20 ?10 0 10 20 30 40 50 60 70 80 1.1 1.0 0.9 0.8 0.7 0.6 0.5 0.4 de = re = gnd de = re = x* *x = don?t care figure 15. supply current vs. temperature 90 0 ?40 05524-021 temperature (c) shutdown current (na) ?30 ?20 ?10 0 10 20 30 40 50 60 70 80 80 70 60 50 40 30 20 10 figure 16. shutdown current vs. temperature
data sheet adm3483/adm3485/adm 3488/adm3490/adm3491 rev. e | page 11 of 20 test circuits r l /2 r l /2 v oc a / y b/z v od 05524-003 figure 17. differential output voltage and common-mode voltage drivers v cm = ?7v to +12v v cc r l 375 ? 375 ? v od d 05524-004 figure 18. differential output voltage drivers with varying common-mode voltage 0 5524-005 i oh (?) i ol (+) v oh v ol r 0 v id figure 19. cmos output voltage high and cmos output voltage low receivers d generator 1 v cc 50? c l r l = 60 ? c l = 15pf 2 05524-036 out 1 ppr = 250khz, 50% duty cycle, t r 6.0ns, z o =50 ? . 2 c l includes probe and stray capacitance. figure 20. driver differential output delay and transition times d v om r l =27 ? out c l =15pf 2 generator 1 v cc 50? s1 v om = v oh +v ol 2 1.5v 05524-037 1 ppr = 250khz, 50% duty cycle, t r 6.0ns, z o =50 ? . 2 c l includes probe and stray capacitance. figure 21. driver propagation delays d out c l = 50pf 2 generator 1 50? s1 v om = v oh +v ol 2 1.5v r l = 110 ? 0v or 3v 05524-038 1 ppr = 250khz, 50% duty cycle, t r 6.0ns, z o =50 ? . 2 c l includes probe and stray capacitance. figure 22. driver enable and disable times (t pzh , t psh , t phz )
adm3483/adm3485/adm 3488/adm3490/adm3491 data sheet rev. e | page 12 of 20 d out c l = 50pf 2 generator 1 50? s1 0v or 3v v cc r l =110 ? 05524-039 1 ppr = 250khz, 50% duty cycle, t r 6.0ns, z o =50 ? . 2 c l includes probe and stray capacitance. figure 23. driver enable and disable times (t pzl , t psl , t plz ) 05524-040 generator 1 50? c l =15pf 2 r 1.5v 0 v om = v cc 2 out v id 1 ppr = 250khz, 50% duty cycle, t r 6.0ns, z o =50 ? . 2 c l includes probe and stray capacitance. figure 24. receiver propagation delays r generator 1 50 ? c l 2 s3 s1 s2 v cc +1.5v ?1.5v v id 1k ? 05524-041 1 ppr = 250khz, 50% duty cycle, t r 6.0ns, z o =50 ? . 2 c l includes probe and stray capacitance. figure 25. receiver enable and disable times
data sheet adm3483/adm3485/adm 3488/adm3490/adm3491 rev. e | page 13 of 20 switching characteristics in out 1.5v 1.5v +3 v 0 +2v ?2v t dd t dd t td t td 50% 50% 10% 10% 90% 90% 05524-006 figure 26. driver differential output delay and transition times 3 v 0v v oh v ol v oh v ol v om v om v om v om in a/y out b/z out 1.5v 1.5v t plh t phl t phl t plh 05524-007 figure 27. driver propagation delays 0 v oh 0 3 v 1.5v 1.5v 0.25v in out v om t pzh t phz 05524-008 figure 28. driver enable and disable times (t pzh , t psh , t phz ) v ol v cc 0 3 v 0.25v in out 1.5v 1.5v t psl t plz v om 05524-009 figure 29. driver enable and disable times (t pzl , t psl , t plz ) 05524-010 3 v 0 v cc 0 in out v om v om 1.5v 1.5v t rphl t rplh figure 30. receiver propagation delays +3 v 0 v oh 0 s1 open s2 closed s3 = +1.5v s1 closed s2 open s3 = ?1.5v s1 open s2 closed s3 = +1.5v s1 closed s2 open s3 = ?1.5v +3 v 0 v cc v ol +3v 0 v cc v ol +3v 0 v oh 0 1.5v 1.5v 1.5v in out in out in out in out t przl t prsl t prlz t prhz +0.25v +0.25v 1.5v 1.5v 1.5v t przh t prsh 0 5524-011 figure 31. receiver enable and disable times
adm3483/adm3485/adm 3488/adm3490/adm3491 data sheet rev. e | page 14 of 20 circuit description the adm3483/adm3485/adm3488/adm3490/adm3491 are low power transceivers for rs-485 and rs-422 communications. the adm3483/adm3488 transmit and receive at data rates up to 250 kbps; the adm3485/adm3490/adm3491 transmit at up to 10 mbps. the adm3488/adm3490/adm3491 are full-duplex transceivers, while the adm3483/adm3485 are half-duplex transceivers. driver enable (de) and receiver enable ( re ) pins are included on the adm3483/adm3485/adm3491. when disabled, the driver and receiver outputs are high impedance. devices with receiver/driver enables (adm3483/adm3485/adm3491) table 8. transmitting truth table transmitting input transmitting output re de di b 1 a 1 mode x 2 1 1 0 1 normal x 2 1 0 1 0 normal 0 0 x 2 high-z 3 high-z 3 normal 1 0 x 2 high-z 3 high-z 3 shutdown 1 a and b outputs are y an d z, respectively, for fu ll-duplex part (adm3491). 2 x = dont care. 3 high-z = high impedance. table 9. receiving truth table receiving input receiving output re de 1 a C b ro mode 0 0 +0.2 v 1 normal 0 0 ?0.2 v 0 normal 0 0 inputs open 1 normal 1 0 x 2 high-z 3 shutdown 1 de is a dont care; x for the full-duplex part (adm3491). 2 x = dont care. 3 high-z = high impedance. devices without receiver/driver enables adm3488/adm3490 table 10. transmitting truth table transmitting input transmitting output di z y 1 0 1 0 1 0 table 11. receiving truth table receiving input receiving output a C b ro +0.2 v 1 ?0.2 v 0 inputs open 1 reduced emi and reflections (adm3483/adm3488) the adm3483/adm3488 are slew rate limited transceivers, minimizing emi and reducing reflections caused by improperly terminated cables. low power shutdown mode (adm3483/adm3485/adm3491) a low power shutdown mode is initiated by bringing re high and de low. the devices do not shut down unless both the driver and receiver are disabled (high impedance). in shutdown mode, the devices typically draw only 2 na of supply current. for these devices, the t psh and t psl enable times assume the part is in the low power shutdown mode; the t pzh and t pzl enable times assume the receiver or driver was disabled, but the part is not shut down. driver output protection two methods are implemented to prevent excessive output current and power dissipation caused by faults or by bus contention. current limit protection on the output stage provides immediate protection against short circuits over the whole common-mode voltage range (see the typical performance characteristics section). in addition, a thermal shutdown circuit forces the driver outputs into a high impedance state if the die temperature rises excessively. propagation delay skew time is the difference between the low-to-high and high- to-low propagation delays. small driver/receiver skew times help maintain a symmetrical mark-space ratio (50% duty cycle). the receiver skew time (|t prlh ? t prhl |) is under 10 ns (20 ns for adm3483/adm3488). the driver skew times are 8 ns for adm3485/adm3490/adm3491 and typically under 100 ns for adm3483/adm3488. typical applications the adm3483/adm3485/adm3491 transceivers are designed for half-duplex bidirectional data communications on multipoint bus transmission lines, figure 32 and figure 33 show typical network applications circuits. the adm3488 and the adm3490 full-duplex transceivers are designed to be used in a daisy-chain network topology or in a point-to-point application, see figure 34 and figure 35 . the adm3491 can be used as line repeat figure 36 . to minimize reflections, the line must be terminated at both ends in its characteristic impedance, and stub lengths off the main line must be kept as short as possible. the slew rate limited adm3483/adm3488 are more tolerant of imperfect termination.
data sheet adm3483/adm3485/adm 3488/adm3490/adm3491 rev. e | page 15 of 20 line length vs. data rate the rs-485 and rs-422 standards cover line lengths up to 4000 feet. for line lengths greater than 4000 feet, see figure 36 . b a r d ro re di de adm3483/ adm3485 adm3483/ adm3485 adm3483/ adm3485 adm3483/ adm3485 b a r d ro re di de b a r d ro re di de b a r d ro re di de 05524-022 ma x imum number of transcei v ers on bus = 32 r t r t notes 1. r t is equal to the characteristic impedance of the cable. v cc r1 r2 figure 32. adm3483/adm3485 typical half-duplex rs-485 network r d ro re di de adm3491 adm3491 a b z y 05524-090 r d ro dide a b z y re r d ro di de adm3491 master slave slave a b z y re maximum number of nodes = 32 adm3491 r d ro dide a b z y re slave notes 1. r t is equal to the characteristic impedance of the cable. r t r t r t v cc r1 r2 r t v cc r1 r2 figure 33. adm3491 typical full-duplex rs-485 network
adm3483/adm3485/adm 3488/adm3490/adm3491 data sheet rev. e | page 16 of 20 b a r d ro di y z b a y z ro di r d r d ro r d master adm3488/ adm3490 adm3488/ adm3490 adm3488/ adm3490 slave slave adm3488/ adm3490 slave abzy abzy di ro di 05524-042 figure 34. adm3488/adm3490 full-duplex daisy-chain network b a r d ro di y z master adm3488/ adm3490 r d ro di b a y z slave adm3488/ adm3490 0 5524-043 figure 35. adm3488/adm3490 full-duplex point-to-point applications r d ro re di de adm3491 a b z y data in data out 05524-091 notes 1. r t is equal to the characteristic impedance of the cable. r t r t figure 36. line repeater for adm3491
data sheet adm3483/adm3485/adm 3488/adm3490/adm3491 rev. e | page 17 of 20 outline dimensions 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-012-aa 012407-a 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 (0.1968) 4.80 (0.1890) 4.00 (0.1574) 3.80 (0.1497) 1.27 (0.0500) bsc 6.20 (0.2441) 5.80 (0.2284) 0.51 (0.0201) 0.31 (0.0122) coplanarity 0.10 figure 37. 8-lead standard small outline package [soic_n] narrow body (r-8) dimensions shown in millimeters and (inches) 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-012-ab 060606-a 14 8 7 1 6.20 (0.2441) 5.80 (0.2283) 4.00 (0.1575) 3.80 (0.1496) 8.75 (0.3445) 8.55 (0.3366) 1.27 (0.0500) bsc seating plane 0.25 (0.0098) 0.10 (0.0039) 0.51 (0.0201) 0.31 (0.0122) 1.75 (0.0689) 1.35 (0.0531) 0.50 (0.0197) 0.25 (0.0098) 1.27 (0.0500) 0.40 (0.0157) 0.25 (0.0098) 0.17 (0.0067) coplanarity 0.10 8 0 45 figure 38. 14-lead narrow body small outline [soic_n] narrow body (r-14) dimensions shown in millimeters and (inches)
adm3483/adm3485/adm 3488/adm3490/adm3491 data sheet rev. e | page 18 of 20 ordering guide model 1 temperature range package description package option ordering quantity adm3483arz ? 40c to +85c 8-lead narrow body small outline (soic_n) r-8 adm3483arzCreel7 ? 40c to +85c 8-lead narrow body small outline (soic_n) r-8 1,000 adm3485arz ? 40c to +85c 8-lead narrow body small outline (soic_n) r-8 adm3485arzCreel7 ? 40c to +85c 8-lead narrow body small outline (soic_n) r-8 1,000 adm3488arz ? 40c to +85c 8-lead narrow body small outline (soic_n) r-8 adm3488arzCreel7 ? 40c to +85c 8-lead narrow body small outline (soic_n) r-8 1,000 adm3490arz ? 40c to +85c 8-lead narrow body small outline (soic_n) r-8 adm3490arzCreel7 ? 40c to +85c 8-lead narrow body small outline (soic_n) r-8 1,000 adm3491ar ?40c to +85c 14-lead narrow body small outline (soic_n) r-14 adm3491ar-reel ?40c to +85c 14-lead narrow body small outline (soic_n) r-14 2,500 adm3491ar-reel7 ?40c to +85c 14-lead narr ow body small outline (soic_n) r-14 1,000 adm3491arz ?40c to +85c 14-lead narrow body small outline (soic_n) r-14 adm3491arz-reel ?40c to +85c 14-lead narrow body small outline (soic_n) r-14 2,500 adm3491arz-reel7 ?40c to +85c 14-lead narr ow body small outline (soic_n) r-14 1,000 1 z = rohs compliant part.
data sheet adm3483/adm3485/adm 3488/adm3490/adm3491 rev. e | page 19 of 20 notes
adm3483/adm3485/adm 3488/adm3490/adm3491 data sheet rev. e | page 20 of 20 notes ?2005-2011 analog devices, inc. all rights reserved. trademarks and registered trademarks are the property of their respective owners. d05524-0-11/11(e)

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