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3.3 v slew rate limited, half- and full-duplex, rs-485/rs-422 transceivers adm3483/adm3485/adm3488/adm3490/adm3491 rev. b 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 ?2006 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 rev. b | 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 specificationsadm3483/adm3485/adm3488/ adm3490/adm3491 .................................................................. 6 absolute maximum ratings............................................................ 7 esd caution.................................................................................. 7 pin configurations and function descriptions ........................... 8 test circuits....................................................................................... 9 switching characteristics .............................................................. 11 typical performance characteristics ........................................... 12 circuit description......................................................................... 14 devices with receiver/driver enables adm3483/adm3485/adm3491............................................ 14 devices without receiver/driver enables adm3488/adm3490................................................................ 14 reduced emi and reflectionsadm3483/adm3488 ....... 14 low power shutdown mode..................................................... 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 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
adm3483/adm3485/adm 3488/adm3490/adm3491 rev. b | 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 rev. b | 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 7 ) 1.5 v r l = 54 (rs-485) (see figure 7 ) 1.5 v r l = 60 (rs-485), v cc = 3.3 v (see figure 8 ) |v od | for complementary output states 1 0.2 v r l = 54 or 100 (see figure 7 ) common-mode output voltage (v oc ) 3 v r l = 54 or 100 (see figure 7 ) |v oc | for common-mode output voltage 1 0.2 v r l = 54 or 100 (see figure 7 ) driver input logic cmos input logic threshold low (v ih ) 0.8 v de, di, re cmos input logic threshold high (v il ) 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 9 ) cmos output voltage low (v ol ) 0.4 v i out = 2.5 ma, v id = 200 mv (see figure 9 ) 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.
adm3483/adm3485/adm 3488/adm3490/adm3491 rev. b | 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 10 and figure 16 ) differential output transition time (t td ) 3 8 25 ns r l = 60 ( see figure 10 and figure 16 ) propagation delay, low-to-high level (t plh ) 7 22 35 ns r l = 27 ( see figure 11 and figure 17 ) propagation delay, high-to-low level (t phl ) 7 22 35 ns r l = 27 ( see figure 11 and figure 17 ) |t plh C t phl | propagation delay skew 1 (t pds ) 8 ns r l = 27 ( see figure 11 and figure 17 ) 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 13 and figure 19 ) output enable time to high level (t pzh ) 45 90 ns r l = 110 ( see figure 12 and figure 18 ) output disable time from high level (t phz ) 40 80 ns r l = 110 ( see figure 12 and figure 18 ) output disable time from low level (t plz ) 40 80 ns r l = 110 ( see figure 13 and figure 19 ) output enable time from shutdown to low level (t psl ) 650 900 ns r l = 110 ( see figure 13 and figure 19 ) output enable time from shutdown to high level (t psh ) 650 900 ns r l = 110 ( see figure 12 and figure 18 ) 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 10 and figure 16 ) differential output transition time (t td ) 400 700 1200 ns r l = 60 ( see figure 10 and figure 16 ) propagation delay, low-to-high level (t plh ) 700 1000 1500 ns r l = 27 ( see figure 11 and figure 17 ) propagation delay, high-to-low level (t phl ) 700 1000 1500 ns r l = 27 ( see figure 11 and figure 17 ) |t plh C t phl | propagation delay skew 1 (t pds ) 100 ns r l = 27 ( see figure 11 and figure 17 ) driver output enable/disable times (adm3483 only) output enable time to low level (t pzl ) 900 1300 ns r l = 110 ( see figure 13 and figure 19 ) output enable time to high level (t pzh ) 600 800 ns r l = 110 ( see figure 12 and figure 18 ) output disable time from high level (t phz ) 50 80 ns r l = 110 ( see figure 12 and figure 18 ) output disable time from low level (t plz ) 50 80 ns r l = 110 ( see figure 13 and figure 19 ) output enable time from shutdown to low level (t psl ) 1.9 2.7 s r l = 110 ( see figure 13 and figure 19 ) output enable time from shutdown to high level (t psh ) 2.2 3.0 s r l = 110 ( see figure 12 and figure 18 ) 1 measured on |t plh (y) ? t phl (y)| and |t plh (z) ? t phl (z)|.
adm3483/adm3485/adm 3488/adm3490/adm3491 rev. b | 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 14 and figure 20 ) 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 14 and figure 20 ) 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 14 and figure 20 ) 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 15 and figure 21 ) output enable time to high level (t przh ) 25 50 ns c l = 15 pf (see figure 15 and figure 21 ) output disable time from high level (t prhz ) 25 45 ns c l = 15 pf (see figure 15 and figure 21 ) output disable time from low level (t prlz ) 25 45 ns c l = 15 pf (see figure 15 and figure 21 ) output enable time from shutdown to low level (t prsl ) 720 1400 ns c l = 15 pf (see figure 15 and figure 21 ) output enable time from shutdown to high level (t prsh ) 720 1400 ns c l = 15 pf (see figure 15 and figure 21 ) 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.
adm3483/adm3485/adm 3488/adm3490/adm3491 rev. b | 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 v cc + 0.3 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 rev. b | 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 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 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 4. adm3483/adm3485 pin configuration figure 5. adm3488/adm3490 pin configuration 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 n/a 3 re receiver output enable. a low level enables the receiver output, ro. a high level plac es it in a high impedance state. if re is high and de is low, the device enters a low power shutdown mode. 3 n/a 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. n/a 5 9 y noninverting driver output. n/a 6 10 z inverting driver output. 6 n/a n/a a noninverting receiver input a and noninverting driver output a. n/a 8 12 a noninverting receiver input a. 7 n/a n/a b inverting receiver input b and inverted driver output b. n/a 7 11 b inverting receiver input b. 8 1 13, 14 v cc power supply (3.3 v 0.3 v). n/a n/a 1, 8 nc no connect.
adm3483/adm3485/adm 3488/adm3490/adm3491 rev. b | page 9 of 20 test circuits r l /2 r l /2 v oc a / y b/z v od 05524-003 figure 7. 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 8. 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 9. 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 10. 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 11. 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 12. driver enable and disable times (t pzh , t psh , t phz )
adm3483/adm3485/adm 3488/adm3490/adm3491 rev. b | page 10 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 13. 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 14. 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 15. receiver enable and disable times
adm3483/adm3485/adm 3488/adm3490/adm3491 rev. b | page 11 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 16. 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 17. 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 18. 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 19. 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 20. 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 21. receiver enable and disable times
adm3483/adm3485/adm 3488/adm3490/adm3491 rev. b | page 12 of 20 05524-012 output voltage (v) output current (ma) typical performance characteristics 30 0 03 . 5 25 20 15 10 5 0.5 1.0 1.5 2.0 2.5 3.0 figure 22. output current vs. receiver output low voltage ? 16 0 03 . 5 0.8 0 ?40 05524-015 temperature (c) output voltage (v) 0.7 0.6 0.5 0.4 0.3 0.2 0.1 ?30 ?20 ?10 0 10 20 30 40 50 60 70 80 05524-013 output voltage (v) output current (ma) ?14 ?12 ?10 ?8 ?6 ?4 ?2 0.5 1.0 1.5 2.0 2.5 3.0 figure 23. 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 24. receiver output high voltage vs. temperature, i ro = 1.5 ma figure 25. receiver output low voltage vs. temperature, i ro = 2.5 ma 100 0 03 . 5 05524-016 output voltage (v) output current (ma) 90 80 70 60 50 40 30 20 10 0.5 1.0 1.5 2.0 2.5 3.0 figure 26. 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 27. driver differential output voltage vs. temperature, r l = 54
adm3483/adm3485/adm 3488/adm3490/adm3491 rev. b | page 13 of 20 05524-018 output voltage (v) output current (ma) 140 0 01 2 1.2 0.3 ?40 05524-020 temperature (c) supply current (ma) 120 100 80 60 40 20 246810 1.1 1.0 0.9 0.8 0.7 0.6 0.5 0.4 figure 28. 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 29. output current vs. driver output high voltage ?30 ?20 ?10 0 10 20 30 40 50 60 70 80 de = re = gnd de = re = x* *x = don?t care figure 30. 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 31. shutdown current vs. temperature
adm3483/adm3485/adm 3488/adm3490/adm3491 rev. b | page 14 of 20 circuit description the adm3483/adm3485/adm3488/adm3490/adm3491 are low power transceivers for rs-485 and rs-422 communi- cations. the adm3483/adm3488 transmit and receive at data rates up to 250 kbps; the adm3485/adm3490/adm3491 trans- mit 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 z and y respecti vely, for full-dup lex 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 improp- erly 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 ther- mal 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.
adm3483/adm3485/adm 3488/adm3490/adm3491 rev. b | 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 dide 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 m a x imum 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 rev. b | 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
adm3483/adm3485/adm 3488/adm3490/adm3491 rev. b | page 17 of 20 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 (0.1968) 4.80 (0.1890) 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-012-aa 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 coplanarity 0.10 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) 8 0 0.50 (0.0197) 0.25 (0.0098) 1.27 (0.0500) 0.40 (0.0157) 0.25 (0.0098) 0.17 (0.0067) 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 rev. b | page 18 of 20 ordering guide model temperature range package descript ion package option ordering quantity adm3483arz 1 ? 40c to +85c 8-lead narrow body small outline (soic_n) r-8 adm3483arzCreel7 1 ? 40c to +85c 8-lead narrow body small outline (soic_n) r-8 1,000 adm3485arz 1 ? 40c to +85c 8-lead narrow body small outline (soic_n) r-8 adm3485arzCreel7 1 ? 40c to +85c 8-lead narrow body small outline (soic_n) r-8 1,000 adm3488arz 1 ? 40c to +85c 8-lead narrow body small outline (soic_n) r-8 adm3488arzCreel7 1 ? 40c to +85c 8-lead narrow body small outline (soic_n) r-8 1,000 adm3490arz 1 ? 40c to +85c 8-lead narrow body small outline (soic_n) r-8 adm3490arzCreel7 1 ? 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 1 ?40c to +85c 14-lead narrow bo dy small outline (soic_n) r-14 ADM3491ARZ-reel 1 ?40c to +85c 14-lead narrow body small outline (soic_n) r-14 2,500 ADM3491ARZ-reel7 1 ?40c to +85c 14-lead narrow body small outline (soic_n) r-14 1,000 1 z = pb-free part.
adm3483/adm3485/adm 3488/adm3490/adm3491 rev. b | page 19 of 20 notes
adm3483/adm3485/adm 3488/adm3490/adm3491 rev. b | page 20 of 20 notes ?2006 analog devices, inc. all rights reserved. trademarks and registered trademarks are the property of their respective owners. d05524-0-10/06(b)

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