View ADM2587E_4151068.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

signal and power isolated rs-485 transceiver with 15 kv esd protection adm2582e/ADM2587E rev. 0 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 ?2009 analog devices, inc. all rights reserved. features isolated rs-485/rs-422 transceiver, configurable as half or full duplex iso power? integrated isolated dc-to-dc converter 15 kv esd protection on rs-485 input/output pins complies with ansi/tia/eia-485-a-98 and iso 8482:1987(e) adm2582e data rate: 16 mbps ADM2587E data rate: 500 kbps 5 v or 3.3 v operation connect up to 256 nodes on one bus open- and short-circuit, fail-safe receiver inputs high common-mode transient immunity: >25 kv/s thermal shutdown protection safety and regulatory approvals (pending) ul recognition: 2500 v rms for 1 minute per ul 1577 vde certificates of conformity din v vde v 0884-10 (vde v 0884-10):2006-12 v iorm = 560 v peak operating temperature range: ?40c to +85c highly integrated, 20-lead, wide-body soic package applications isolated rs-485/rs-422 interfaces industrial field networks multipoint data transmission systems functional block diagram adm2582e/ADM2587E txd a b y z de v cc rxd re isolation barrier transceiver gnd 1 gnd 2 encode encode decode decode d r decode encode oscillator rectifier regulator v isoout digital isolation i coupler iso power dc-to-dc converter v isoin 08111-001 figure 1. general description the adm2582e/ADM2587E are fully integrated signal and power isolated data transceivers with 15 kv esd protection and are suitable for high speed communication on multipoint transmission lines. the adm2582e/ADM2587E include an integrated isolated dc-to-dc power supply, which eliminates the need for an external dc-to-dc isolation block. they are designed for balanced transmission lines and comply with ansi/tia/eia-485-a-98 and iso 8482:1987(e). the devices integrate analog devices, inc., i coupler? technology to combine a 3-channel isolator, a three-state differential line driver, a differential input receiver, and analog devices iso power dc-to- dc converter into a single package. the devices are powered by a single 5 v or 3.3 v supply, realizing a fully integrated signal and power isolated rs-485 solution. the adm2582e/ADM2587E driver has an active high enable. an active low receiver enable is also provided that causes the receiver output to enter a high impedance state when disabled. the devices have current limiting and thermal shutdown features to protect against output short circuits and situations where bus contention may cause excessive power dissipation. the parts are fully specified over the industrial temperature range and are available in a highly integrated, 20-lead, wide- body soic package. the adm2582e/ADM2587E contain iso power technology that uses high frequency switching elements to transfer power through the transformer. special care must be taken during printed circuit board (pcb) layout to meet emissions standards. refer to application note an-0971, control of radiated emissions with isopower devices , for details on board layout considerations.
adm2582e/ADM2587E rev. 0 | page 2 of 20 table of contents features .............................................................................................. 1 ? applications ....................................................................................... 1 ? functional block diagram .............................................................. 1 ? general description ......................................................................... 1 ? revision history ............................................................................... 2 ? specifications ..................................................................................... 3 ? adm2582e timing specifications ............................................ 4 ? ADM2587E timing specifications ............................................ 4 ? adm2582e/ADM2587E package characteristics ................... 4 ? adm2582e/ADM2587E regulatory information .................. 5 ? adm2582e/ADM2587E insulation and safety-related specifications ................................................................................ 5 ? adm2582e/ADM2587E vde 0884 insulation characteristics (pending) ............................................................ 5 ? absolute maximum ratings ............................................................ 6 ? esd caution .................................................................................. 6 ? pin configuration and function descriptions ............................. 7 ? typical performance characteristics ............................................. 8 ? test circuits ..................................................................................... 12 ? switching characteristics .............................................................. 13 ? circuit description......................................................................... 14 ? signal isolation ........................................................................... 14 ? power isolation ........................................................................... 14 ? truth tables................................................................................. 14 ? thermal shutdown .................................................................... 14 ? open- and short-circuit, fail-safe receiver inputs.............. 14 ? dc correctness and magnetic field immunity ........................... 15 ? applications information .............................................................. 16 ? pcb layout ................................................................................. 16 ? emi considerations ................................................................... 16 ? insulation lifetime ..................................................................... 16 ? isolated power supply considerations .................................... 17 ? typical applications ................................................................... 19 ? outline dimensions ....................................................................... 20 ? ordering guide .......................................................................... 20 ? revision history 9/09revision 0: initial version
adm2582e/ADM2587E rev. 0 | page 3 of 20 specifications all voltages are relative to their respective ground; 3.0 v cc 5.5 v. all minimum/maximum specifications apply over the entire recommended operation range, unless otherwise noted. all typical specifications are at t a = 25c, v cc = 5 v unless otherwise noted. table 1. parameter symbol min typ max unit test conditions ADM2587E supply current i cc data rate 500 kbps 90 ma v cc = 3.3 v, 100 load between y and z 72 ma v cc = 5 v, 100 load between y and z 125 ma v cc = 3.3 v, 54 load between y and z 98 ma v cc = 5 v, 54 load between y and z 120 ma 120 load between y and z adm2582e supply current i cc data rate = 16 mbps 150 ma 120 load between y and z 230 ma 54 load between y and z isolated supply voltage v isout 3.3 driver differential outputs differential output voltage, loaded |v od2 | 2.0 5.0 v r l = 100 (rs-422), see figure 23 1.5 5.0 v r l = 54 (rs-485), see figure 23 |v od3 | 1.5 5.0 v ?7 v v test1 12 v, see figure 24 |v od | for complementary output states |v od | 0.2 v r l = 54 or 100 , see figure 23 common-mode output voltage v oc 3.0 v r l = 54 or 100 , see figure 23 |v oc | for complementary output states |v oc | 0.2 v r l = 54 or 100 , see figure 23 short-circuit output current i os 200 ma output leakage current (y, z) i o 30 a de = 0 v, re = 0 v, v cc = 0 v or 3.6 v, v in = 12 v ?30 a de = 0 v, re = 0 v, v cc = 0 v or 3.6 v, v in = ?7 v logic inputs de, re , txd input threshold low v il 0.3 v cc v de, re , txd input threshold high v ih 0.7 v cc v de, re , txd input current i i ?10 0.01 10 a de, re , txd receiver differential inputs differential input threshold voltage v th ?200 ?125 ?30 mv ?7 v < v cm < +12 v input voltage hysteresis v hys 15 mv v oc = 0 v input current (a, b) i i 125 a de = 0 v, v cc = 0 v or 3.6 v, v in = 12 v ?100 a de = 0 v, v cc = 0 v or 3.6 v, v in = -7 v line input resistance r in 96 k ?7 v < v cm < +12 v logic outputs output voltage low v ol 0.2 0.4 v i o = 1.5 ma, v a ? v b = ?0.2 v output voltage high v oh v cc ? 0.3 v cc ? 0.2 v i o = ?1.5 ma, v a ? v b = 0.2 v short-circuit current 100 ma common-mode transient immunity 1 25 kv/s v cm = 1 kv, transient magnitude = 800 v 1 cm is the maximum common-mode voltage slew rate that can be sustained while maint aining specification-compliant operation. v cm is the common-mode potential difference between the logic and bus sides. the transient magnitude is the range over which the common-mode is slewed. the comm on-mode voltage slew rates apply to both rising and falling common-mode voltage edges.
adm2582e/ADM2587E rev. 0 | page 4 of 20 adm2582e timing specifications t a = ?40c to +85c. table 2. parameter symbol min typ max unit test conditions driver maximum data rate 16 mbps propagation delay, low to high t dplh 63 100 ns r l = 54 , c l1 = c l2 = 100 pf, see figure 25 and figure 29 propagation delay, high to low t dphl 64 100 ns r l = 54 , c l1 = c l2 = 100 pf, see figure 25 and figure 29 output skew t skew 1 8 ns r l = 54 , c l1 = c l2 = 100 pf, see figure 25 and figure 29 rise time/fall time t dr , t df 15 ns r l = 54 , c l1 = c l2 = 100 pf, see figure 25 and figure 29 enable time t zl , t zh 120 ns r l = 110 , c l = 50 pf, see figure 26 and figure 31 disable time t lz , t hz 150 ns r l = 110 , c l = 50 pf, see figure 26 and figure 31 receiver propagation delay, low to high t rplh 94 110 ns c l = 15 pf, see figure 27 and figure 30 propagation delay, high to low t rphl 95 110 ns c l = 15 pf, see figure 27 and figure 30 output skew 1 t skew 1 12 ns c l = 15 pf, see figure 27 and figure 30 enable time t zl , t zh 15 ns r l = 1 k, c l = 15 pf, see figure 28 and figure 32 disable time t lz , t hz 15 ns r l = 1 k, c l = 15 pf, see figure 28 and figure 32 1 guaranteed by design. ADM2587E timing specifications t a = ?40c to +85c. table 3. parameter symbol min typ max unit test conditions driver maximum data rate 500 kbps propagation delay, low to high t dplh 250 503 700 ns r l = 54 , c l1 = c l2 = 100 pf, see figure 25 and figure 29 propagation delay, high to low t dphl 250 510 700 ns r l = 54 , c l1 = c l2 = 100 pf, see figure 25 and figure 29 output skew t skew 7 100 ns r l = 54 , c l1 = c l2 = 100 pf, see figure 25 and figure 29 rise time/fall time t dr , t df 200 1100 ns r l = 54 , c l1 = c l2 = 100 pf, see figure 25 and figure 29 enable time t zl , t zh 2.5 s r l = 110 , c l = 50 pf, see figure 26 and figure 31 disable time t lz , t hz 200 ns r l = 110 , c l = 50 pf, see figure 26 and figure 31 receiver propagation delay, low to high t rplh 91 200 ns c l = 15 pf, see figure 27 and figure 30 propagation delay, high to low t rphl 95 200 ns c l = 15 pf, see figure 27 and figure 30 output skew t skew 4 30 ns c l = 15 pf, see figure 27 and figure 30 enable time t zl , t zh 15 ns r l = 1 k, c l = 15 pf, see figure 28 and figure 32 disable time t lz , t hz 15 ns r l = 1 k, c l = 15 pf, see figure 28 and figure 32 adm2582e/ADM2587E package characteristics table 4. parameter symbol min typ max unit test conditions resistance (input-to-output) 1 r i-o 10 12 capacitance (input-to-output) 1 c i-o 3 pf f = 1 mhz input capacitance 2 c i 4 pf input ic junction-to-case thermal resistance jci 33 c/w thermocouple located at center of package underside output ic junction-to-case thermal resistance jco 28 c/w thermocouple located at center of package underside 1 device considered a 2-terminal device: short together pin 1 to pin 10 and short together pin 11 to pin 20. 2 input capacitance is from any input data pin to ground.
adm2582e/ADM2587E rev. 0 | page 5 of 20 adm2582e/ADM2587E regulatory information table 5. pending adm2582e/ADM2587E approvals organization approval type notes ul to be recognized under the component recognition program of underwriters laboratories, inc. in accordance with ul 1577, each adm2582e/ADM2587E is proof tested by applying an insulation test voltage 3000 v rms for 1 second. vde to be certified according to din v vde v 0884-10 (vde v 0884-10):2006-12 in accordance with vde 0884-10, each adm2582e/ADM2587E is proof tested by applying an insu lation test voltage 1050 v peak for 1 second. adm2582e/ADM2587E insulation and sa fety-related specifications table 6. parameter symbol value unit conditions rated dielectric insulation voltage 2500 v rms 1-minute duration minimum external air gap (clearance) l(i01) >8.0 mm measured from input termin als to output terminals, shortest distance through air minimum external tracking (creepage) l(i02) >8.0 mm measured from input termin als to output terminals, shortest distance along body minimum internal gap (internal clearance) 0.017 min mm insulation distance through insulation tracking resistance (comparative tracking index) cti >175 v din iec 112/vde 0303-1 isolation group iiia material group (din vde 0110: 1989-01, table 1) adm2582e/ADM2587E vde 0884 insulation characteristics (pending) this isolator is suitable for basic electrical isolation only within the safety limit data. maintenance of the safety data must be ensured by means of protective circuits. table 7. description conditions symbol characteristic unit classifications installation classification per din vde 0110 for rated mains voltage 150 v rms i to iv 300 v rms i to iii 400 v rms i to ii climatic classification 40/85/21 pollution degree din vde 0110, see table 1 2 voltage maximum working insulation voltage v iorm 560 v peak input-to-output test voltage v pr method b1 v iorm 1.875 = v pr , 100% production tested, t m = 1 sec, partial discharge < 5 pc 1050 v peak method a after environmental tests, subgroup 1 v iorm 1.6 = v pr , t m = 60 sec, partial discharge < 5 pc 896 v peak after input and/or safety test, subgroup 2/subgroup 3 v iorm 1.2 = v pr , t m = 60 sec, partial discharge < 5 pc 672 v peak highest allowable overvoltage transient overvoltage, t tr = 10 sec v tr 4000 v peak safety-limiting values maximum value allowed in the event of a failure case temperature t s 150 c input current i s , input 265 ma output current i s , output 335 ma insulation resistance at t s v io = 500 v r s >10 9
adm2582e/ADM2587E rev. 0 | page 6 of 20 absolute maximum ratings t a = 25c, unless otherwise noted. all voltages are relative to their respective ground. table 9. maximum continuous working voltage 1 parameter max unit reference standard ac voltage bipolar waveform 424 v peak 50-year minimum lifetime unipolar waveform basic insulation 600 v peak maximum approved working voltage per iec 60950-1 (pending) reinforced insulation 560 v peak maximum approved working voltage per iec 60950-1 and vde v 0884-10 (pending) dc voltage basic insulation 600 v peak maximum approved working voltage per iec 60950-1(pending) reinforced insulation 560 v peak maximum approved working voltage per iec 60950-1 and vde v 0884-10 (pending) table 8. parameter rating v cc ?0.5 v to +7 v digital input voltage (de, re , txd) ?0.5 v to v dd + 0.5 v digital output voltage (rxd) ?0.5 v to v dd + 0.5 v driver output/receiver input voltage ?9 v to +14 v operating temperature range ?40c to +85c storage temperature range ?55c to +150c esd (human body model) on a, b, y, and z pins 15 kv esd (human body model) on other pins 2 kv lead temperature soldering (10 sec) 260c 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. 1 refers to continuous voltage magni tude imposed across the isolation barrier. see the insulation lifetime section for more details. esd caution
adm2582e/ADM2587E rev. 0 | page 7 of 20 pin configuration and fu nction descriptions gnd 1 1 v cc 2 gnd 1 3 rxd 4 gnd 2 20 v isoin 19 a 18 b 17 re 5 gnd 2 16 de 6 z 15 txd 7 gnd 2 14 v cc 8 y 13 gnd 1 9 v isoout 12 gnd 1 10 gnd 2 11 notes 1. pin 12 and pin 19 must be connected externally. adm2582e ADM2587E top view (not to scale) 08111-002 figure 2. pin configuration table 10. pin function description pin no. mnemonic description 1 gnd 1 ground, logic side. 2 v cc logic side power supply. it is recommended that a 0.1 f and a 10 f decoupling capacitor be fitted between pin 2 and pin 1. 3 gnd 1 ground, logic side. 4 rxd receiver output data. this output is high when (a ? b) > 200 mv and low when (a ? b) < C200 mv. the output is tristated when the rece iver is disabled, that is, when re is driven high. 5 re receiver enable input. this is an active-low input. driving this input low enables the receiver; driving it high disables the receiver. 6 de driver enable input. driving this input high en ables the driver; driving it low disables the driver. 7 txd driver input. data to be transmitted by the driver is appl ied to this input. 8 v cc logic side power supply. it is recommended that a 0.1 f and a 0.01 f decoupling capacitor be fitted between pin 8 and pin 7. 9 gnd 1 ground, logic side. 10 gnd 1 ground, logic side. 11 gnd 2 ground, bus side. 12 v isoout isolated power supply output. this pin must be connected externally to v isoin . it is recommended that a reservoir capacitor of 10 f and a decoupling capacitor of 0.1 f be fitted between pin 12 and pin 11. 13 y driver noninverting output 14 gnd 2 ground, bus side. 15 z driver inverting output 16 gnd 2 ground, bus side. 17 b receiver inverting input. 18 a receiver noninverting input. 19 v isoin isolated power supply input. this pin must be connected externally to v isoout . it is recommended that a 0.1 f and a 0.01 f decoupling capacitor be fitted between pin 19 and pin 20. 20 gnd 2 ground, bus side.
adm2582e/ADM2587E rev. 0 | page 8 of 20 typical performance characteristics 20 0 40 60 80 100 120 140 160 180 ?40?151035608 supply current, i cc (ma) temperature (c) 5 no load r l = 120 ? r l = 54 ? 08111-103 figure 3. adm2582e supply current (i cc ) vs. temperature (data rate = 16 mbps, de = 3.3 v, v cc = 3.3 v) 20 0 40 60 80 100 120 140 ?40 ?15 10 35 60 85 supply current, i cc (ma) temperature (c) r l = 120 ? r l = 54 ? 08111-104 no load figure 4. adm2582e supply current (i cc ) vs. temperature (data rate = 16 mbps, de = 5 v, v cc = 5 v) 20 0 40 60 80 100 120 140 ?40 ?15 10 35 60 85 supply current, i cc (ma) temperature (c) r l = 120 ? r l = 54 ? 08111-105 no load figure 5. ADM2587E supply current (i cc ) vs. temperature (data rate = 500 kbps, de = 5 v, v cc = 5 v) 20 0 40 60 80 100 120 ?40 ?15 10 35 60 85 supply current, i cc (ma) temperature (c) r l = 120 ? r l = 54 ? 08111-106 no load figure 6. ADM2587E supply current (i cc ) vs. temperature (data rate = 500 kbps, de = 3.3 v, v cc = 3.3 v) 50 52 54 56 58 60 62 64 66 68 70 72 driver propagation delay (ns) temperature (c) t dphl t dplh ?40 ?15 10 35 60 85 0 8111-107 figure 7. adm2582e differential driver propagation delay vs. temperature 400 420 440 460 480 500 520 540 560 580 600 driver propagation delay (ns) temperature (c) t dphl t dplh ?40 ?15 10 35 60 85 0 8111-108 figure 8. ADM2587E differential driver propagation delay vs. temperature
adm2582e/ADM2587E rev. 0 | page 9 of 20 ch1 2.0v ch3 2.0v ch2 2.0v txd z y m10.00ns a ch1 1.28v 1 3 08111-109 figure 9. adm2582e driver propagation delay ch1 2.0v ch3 2.0v ch2 2.0v m200ns a ch1 2.56v 1 3 08111-110 txd y z figure 10. ADM2587E driver propagation delay ?70 ?60 ?50 ?40 ?30 ?20 ?10 0 012345 output current (ma) output voltage (v) 08111-111 figure 11. receiver output current vs. receiver output high voltage 0 10 20 30 40 50 60 012345 output current (ma) output voltage (v) 0 8111-112 figure 12. receiver output current vs. receiver output low voltage 4.65 4.66 4.67 4.68 4.69 4.70 4.71 4.72 4.73 4.74 4.75 output voltage(v) temperature (c) ?40 ?15 10 35 60 85 08111-113 figure 13. receiver output high voltage vs. temperature 0.20 0.22 0.24 0.26 0.28 0.30 0.32 output voltage (v) temperature (c) ?40 ?15 10 35 60 85 08111-114 figure 14. receiver output low voltage vs. temperature
adm2582e/ADM2587E rev. 0 | page 10 of 20 b a rxd ch1 2.0v ch3 2.0v ch2 2.0v m10.00ns a ch1 2.56v 1 3 08111-115 figure 15. adm2582e receiver propagation delay ch1 2.0v ch3 2.0v ch2 2.0v m10.00ns a ch1 2.56v 1 3 08111-116 b a rxd figure 16. ADM2587E receiver propagation delay 93 92 94 95 96 97 98 ?40 ?15 10 35 60 85 receiver propa g a tion del a y (ns) temperature (c) t rphl t rplh 08111-117 figure 17. adm2582e receiver propagation delay vs. temperature 90 91 92 93 94 95 96 97 98 99 100 receiver propagation delay (ns) temperature (c) t rphl t rplh ?40 ?15 10 35 60 85 0 8111-118 figure 18. ADM2587E receiver propagation delay vs. temperature 3.26 3.27 3.28 3.29 3.30 3.31 3.32 3.33 isolated supply voltage (v) no load r l = 120 ? r l = 54 ? ?40?151035608 temperature (c) 5 0 8111-119 figure 19. adm2582e isolated supply voltage vs. temperature (v cc = 3.3 v, data rate = 16 mbps) 3.26 3.27 3.28 3.29 3.31 3.33 3.35 3.30 3.32 3.34 3.36 isolated supply voltage (v) no load r l = 120 ? r l = 54 ? ?40?151035608 temperature (c) 5 08111-120 figure 20. adm2582e isolated supply voltage vs. temperature (v cc = 5 v, data rate = 16 mbps)
adm2582e/ADM2587E rev. 0 | page 11 of 20 10 0 20 30 40 50 60 ?40?151035608 iso 5 0 10 15 25 20 30 35 40 ?40?151035608 iso 5 l a ted supply current (ma) temperature (c) no load r l = 120 ? r l = 54 ? 08111-121 5 l a ted supply current (ma) temperature (c) no load r l = 120 ? r l = 54 ? 08111-122 figure 21. adm2582e isolated supply current vs. temperature (v cc = 3.3 v, data rate = 16 mbps) figure 22. ADM2587E isolated supply current vs. temperature (v cc = 3.3 v, data rate = 500 kbps)
adm2582e/ADM2587E rev. 0 | page 12 of 20 test circuits y z t xd v od2 v oc r l r l 2 2 08111-003 figure 23. driver voltage measurement y z t xd v od3 v test 375? 60? 375? 08111-004 figure 24. driver voltage measurement y z t xd c l c l r l 0 8111-005 figure 25. driver propagation delay y z t xd de s1 s2 v cc r l 110 ? v out c l 50pf 08111-006 figure 26. driver enable/disable c l v out re a b 08111-007 figure 27. receiver propagation delay c l r l v out v cc re s1 s2 +1.5 v ? 1.5 v re in 0 8111-008 figure 28. receiver enable/disable
adm2582e/ADM2587E rev. 0 | page 13 of 20 switching characteristics z y t dplh t dr t dphl t df 1/2v o v o 90% point 10% point 90% point 10% point v diff = v (y) ? v (z) ?v o v diff t skew = t dphl ?t dplh +v o 0v v cc v cc /2 v cc /2 08111-009 figure 29. driver propagation delay, rise/fall timing a ? b rxd 0v 1.5v 1.5v v ol v oh t rplh 0v t rphl t skew = | t rplh ? t rphl | 08111-010 figure 30. receiver propagation delay de y , z y , z v cc 0v v ol v oh 0.5v cc 0.5v cc t zl t zh t lz t hz v oh ? 0.5v v ol + 0.5v 2.3v 2.3v 08111-011 figure 31. driver enable/disable timing output low output high 1.5v 1.5v ro ro re 0v 0.5v cc 0.5v cc 0.7v cc 0.3v cc t zl t zh t lz t hz v oh ? 0.5v v ol + 0.5v v ol v oh 08111-012 figure 32. receiver enable/disable timing
adm2582e/ADM2587E rev. 0 | page 14 of 20 circuit description signal isolation the adm2582e/ADM2587E signal isolation is implemented on the logic side of the interface. the part achieves signal isolation by having a digital isolation section and a transceiver section (see figure 1 ). data applied to the txd and de pins and referenced to logic ground (gnd 1 ) are coupled across an isolation barrier to appear at the transceiver section referenced to isolated ground (gnd 2 ). similarly, the single-ended receiver output signal, referenced to isolated ground in the transceiver section, is coupled across the isolation barrier to appear at the rxd pin referenced to logic ground. power isolation the adm2582e/ADM2587E power isolation is implemented using an iso power integrated isolated dc-to-dc converter. the dc-to-dc converter section of the adm2582e/ADM2587E works on principles that are common to most modern power supplies. it is a secondary side controller architecture with isolated pulse- width modulation (pwm) feedback. v cc power is supplied to an oscillating circuit that switches current into a chip-scale air core transformer. power transferred to the secondary side is rectified and regulated to 3.3 v. the secondary (v iso ) side controller regulates the output by creating a pwm control signal that is sent to the primary (v cc ) side by a dedicated i coupler data channel. the pwm modulates the oscillator circuit to control the power being sent to the secondary side. feedback allows for significantly higher power and efficiency. truth tables the truth tables in this section use the abbreviations found in table 11 . table 11. truth table abbreviations letter description h high level l low level x dont care z high impedance (off ) nc disconnected table 12. transmitting (see table 11 for abbreviations) inputs outputs de txd y z h h h l h l l h l x z z x x z z l x z z x x z z table 13. receiving (see table 11 for abbreviations) inputs output a ? b re rxd > ?0.03 v l or nc h < ?0.2 v l or nc l ?0.2 v < a ? b < ?0.03 v l or nc x inputs open l or nc h x h z x l or nc h x l or nc l thermal shutdown the adm2582e/ADM2587E contain thermal shutdown circuitry that protects the parts from excessive power dissipation during fault conditions. shorting the driver outputs to a low impedance source can result in high driver currents. the thermal sensing circuitry detects the increase in die temperature under this condition and disables the driver outputs. this circuitry is designed to disable the driver outputs when a die temperature of 150c is reached. as the device cools, the drivers are reenabled at a temperature of 140c. open- and short-circuit, fail-safe receiver inputs the receiver inputs have open- and short-circuit, fail-safe features that ensure that the receiver output is high when the inputs are open or shorted. during line-idle conditions, when no driver on the bus is enabled, the voltage across a terminating resistance at the receiver input decays to 0 v. with traditional transceivers, receiver input thresholds specified between ?200 mv and +200 mv mean that external bias resistors are required on the a and b pins to ensure that the receiver outputs are in a known state. the short-circuit, fail-safe receiver input feature eliminates the need for bias resistors by specifying the receiver input threshold between ?30 mv and ?200 mv. the guaranteed negative threshold means that when the voltage between a and b decays to 0 v, the receiver output is guaranteed to be high.
adm2582e/ADM2587E rev. 0 | page 15 of 20 dc correctness and magnetic field immunity the digital signals transmit across the isolation barrier using i coupler technology. this technique uses chip-scale transformer windings to couple the digital signals magnetically from one side of the barrier to the other. digital inputs are encoded into waveforms that are capable of exciting the primary transformer winding. at the secondary winding, the induced waveforms are decoded into the binary value that was originally transmitted. positive and negative logic transitions at the isolator input cause narrow (~1 ns) pulses to be sent to the decoder via the transformer. the decoder is bistable and is, therefore, either set or reset by the pulses, indicating input logic transitions. in the absence of logic transitions at the input for more than 1 s, periodic sets of refresh pulses indicative of the correct input state are sent to ensure dc correctness at the output. if the decoder receives no internal pulses of more than approximately 5 s, the input side is assumed to be unpowered or nonfunctional, in which case, the isolator output is forced to a default state by the watchdog timer circuit. this situation should occur in the adm2582e/ADM2587E devices only during power-up and power-down operations. the limitation on the adm2582e/ADM2587E magnetic field immunity is set by the condition in which induced voltage in the transformer receiving coil is sufficiently large to either falsely set or reset the decoder. the following analysis defines the conditions under which this can occur. the 3.3 v operating condition of the adm2582e/ADM2587E is examined because it represents the most susceptible mode of operation. the pulses at the transformer output have an amplitude of >1.0 v. the decoder has a sensing threshold of about 0.5 v, thus establishing a 0.5 v margin in which induced voltages can be tolerated. the voltage induced across the receiving coil is given by v = (? d / dt )? r n 2; n = 1, 2, , n where: is magnetic flux density (gauss). n is the number of turns in the receiving coil. r n is the radius of the nth turn in the receiving coil (cm). given the geometry of the receiving coil in the adm2582e/ ADM2587E and an imposed requirement that the induced voltage be, at most, 50% of the 0.5 v margin at the decoder, a maximum allowable magnetic field is calculated as shown in figure 33 . magnetic field frequency (hz) 100 maximum allowable magnetic flux density (kgauss) 0.001 1m 10 0.01 1k 10k 10m 0.1 1 100m 100k 08111-019 figure 33. maximum allowable external magnetic flux density for example, at a magnetic field frequency of 1 mhz, the maximum allowable magnetic field of 0.2 kgauss induces a voltage of 0.25 v at the receiving coil. this is about 50% of the sensing threshold and does not cause a faulty output transition. similarly, if such an event occurs during a transmitted pulse (and is of the worst-case polarity), it reduces the received pulse from >1.0 v to 0.75 v, which is still well above the 0.5 v sensing threshold of the decoder. the preceding magnetic flux density values correspond to specific current magnitudes at given distances from the adm2582e/ADM2587E transformers. figure 34 expresses these allowable current magnitudes as a function of frequency for selected distances. as shown in figure 34 , the adm2582e/ ADM2587E are extremely immune and can be affected only by extremely large currents operated at high frequency very close to the component. for the 1 mhz example, a 0.5 ka current must be placed 5 mm away from the adm2582e/ADM2587E to affect component operation. magnetic field frequency (hz) maximum allowable current (ka) 1k 100 10 1 0.1 0.01 1k 10k 100m 100k 1m 10m distance = 5mm distance = 1m distance = 100mm 0 8111-020 figure 34. maximum allowable current for various current-to- adm2582e/ADM2587E spacings note that in combinations of strong magnetic field and high frequency, any loops formed by printed circuit board (pcb) traces can induce error voltages sufficiently large to trigger the thresholds of succeeding circuitry. take care in the layout of such traces to avoid this possibility.
adm2582e/ADM2587E rev. 0 | page 16 of 20 applications information pcb layout the adm2582e/ADM2587E isolated rs-422/rs-485 transceiver contains an iso power integrated dc-to-dc converter, requiring no external interface circuitry for the logic interfaces. power supply bypassing is required at the input and output supply pins (see figure 35 ). the power supply section of the adm2582e/ ADM2587E uses an 180 mhz oscillator frequency to pass power efficiently through its chip-scale transformers. in addition, the normal operation of the data section of the i coupler introduces switching transients on the power supply pins. bypass capacitors are required for several operating frequencies. noise suppression requires a low inductance, high frequency capacitor, whereas ripple suppression and proper regulation require a large value capacitor. these capacitors are connected between pin 1 (gnd 1 ) and pin 2 (v cc ) and pin 8 (v cc ) and pin 9 (gnd 1 ) for v cc . the v isoin and v isoout capacitors are connected between pin 11 (gnd 2 ) and pin 12 (v isoout ) and pin 19 (v isoin ) and pin 20 (gnd 2 ). to suppress noise and reduce ripple, a parallel combination of at least two capacitors is required. the recommended capacitor values are 0.1 f and 10 f. the recommended best practice is to use a very low inductance ceramic capacitor, or its equivalent, for the smaller value. the total lead length between both ends of the capacitor and the input power supply pin should not exceed 10 mm. v cc 2 g nd 1 3 rxd 4 gnd 2 20 v isoin 19 a 18 b 17 re 5 gnd 2 16 de 6 z 15 txd 7 gnd 2 14 v cc 8 y 13 g nd 1 9 v isoout 12 g nd 1 10 gnd 2 11 g nd 1 1 0 8111-125 figure 35. recommended pcb layout in applications involving high common-mode transients, ensure that board coupling across the isolation barrier is minimized. furthermore, design the board layout such that any coupling that does occur equally affects all pins on a given component side. failure to ensure this can cause voltage differentials between pins exceeding the absolute maximum ratings for the device, thereby leading to latch-up and/or permanent damage. the adm2582e/ADM2587E dissipate approximately 650 mw of power when fully loaded. because it is not possible to apply a heat sink to an isolation device, the devices primarily depend on heat dissipation into the pcb through the gnd pins. if the devices are used at high ambient temperatures, provide a thermal path from the gnd pins to the pcb ground plane. the board layout in figure 35 shows enlarged pads for pin 1, pin 3, pin 9, pin 10, pin 11, pin 14, pin 16, and pin 20. implement multiple vias from the pad to the ground plane to reduce the temperature inside the chip significantly. the dimensions of the expanded pads are at the discretion of the designer and dependent on the available board space. emi considerations the dc-to-dc converter section of the adm2582e/ADM2587E components must, of necessity, operate at very high frequency to allow efficient power transfer through the small transformers. this creates high frequency currents that can propagate in circuit board ground and power planes, causing edge and dipole radiation. grounded enclosures are recommended for applications that use these devices. if grounded enclosures are not possible, good rf design practices should be followed in the layout of the pcb. see application note an-0971, control of radiated emissions with isopower devices , for more information. insulation lifetime all insulation structures eventually break down when subjected to voltage stress over a sufficiently long period. the rate of insulation degradation is dependent on the characteristics of the voltage waveform applied across the insulation. analog devices conducts an extensive set of evaluations to determine the lifetime of the insulation structure within the adm2582e/ADM2587E. accelerated life testing is performed using voltage levels higher than the rated continuous working voltage. acceleration factors for several operating conditions are determined, allowing calculation of the time to failure at the working voltage of interest. the values shown in table 9 summarize the peak voltages for 50 years of service life in several operating conditions. in many cases, the working voltage approved by agency testing is higher than the 50-year service life voltage. operation at working voltages higher than the service life voltage listed leads to premature insulation failure. the insulation lifetime of the adm2582e/ADM2587E depends on the voltage waveform type imposed across the isolation barrier. the i coupler insulation structure degrades at different rates, depending on whether the waveform is bipolar ac, unipolar ac, or dc. figure 36 , figure 37 , and figure 38 illustrate these different isolation voltage waveforms. bipolar ac voltage is the most stringent environment. a 50-year operating lifetime under the bipolar ac condition determines the analog devices recommended maximum working voltage.
adm2582e/ADM2587E rev. 0 | page 17 of 20 in the case of unipolar ac or dc voltage, the stress on the insulation is significantly lower. this allows operation at higher working voltages while still achieving a 50-year service life. the working voltages listed in table 9 can be applied while maintaining the 50-year minimum lifetime, provided the voltage conforms to either the unipolar ac or dc voltage cases. any crossinsulation voltage waveform that does not conform to figure 37 or figure 38 should be treated as a bipolar ac waveform, and its peak voltage should be limited to the 50-year lifetime voltage value listed in table 9 . 0v rated peak voltage 08111-021 figure 36. bipolar ac waveform 0v rated peak voltage 08111-023 figure 37. dc waveform 0v rated peak voltage notes 1. the voltage is shown as sinusodial for illustration purposes only. it is meant to represent any voltage waveform varying between 0 and some limiting value. the limiting value can be positive or negative, but the voltage cannot cross 0v. 08111-022 figure 38. unipolar ac waveform isolated power supply considerations the typical output voltage of the integrated iso power dc-to-dc isolated supply is 3.3 v. the isolated supply in the ADM2587E is capable of supplying a current of 55 ma when the junction temperature of the device is kept below 120c. it is important to note that the current available on the v isoout pin is the total current available and includes the current required to supply the internal rs-485 circuitry. the ADM2587E can typically supply 15 ma externally on v isoout when the driver is switching at 500 kbps loaded with 54 , while the junction temperature of the part is less than 120c. table 14. typical maximum external current available on v isoout external load current (ma) r t system configuration 15 54 double terminated bus with r t = 110 29 120 single terminated bus 46 unloaded unterminated bus the adm2582e typically has no current available externally on v isoout . when external current is drawn from the v isoout pin, there is an increased risk of generating radiated emissions due to the high frequency switching elements used in the iso power dc to- dc converter. special care must be taken during pcb layout to meet emissions standards. see application note an-0971, control of radiated emissions with isopower devices , for details on board layout considerations. adm2582e/ADM2587E txd a b y z de v cc v cc v cc rxd re isolation barrier transceiver gnd 1 gnd 2 gnd 2 gnd 1 r t encode encode decode decode d r decode encode oscillator rectifier regulator external load v isoout digital isolation i coupler iso power dc-to-dc converter v isoin 08111-038 500kbps gnd figure 39. ADM2587E typical maximum external current measurements
adm2582e/ADM2587E rev. 0 | page 18 of 20 adm2582e/ADM2587E txd a b y z de rxd re isolation barrier transceiver gnd 1 gnd 1 gnd 2 encode encode encode decode decode decode d r oscillator rectifier regulator v isoout v cc v cc v isoin microcontroller and uart r t r t 3.3v/5v power supply 100nf 10f 100nf 10nf 100nf 10f 100nf 10nf digital isolation i coupler iso power dc-to-dc converter 0 8111-124 figure 40. example circuit diagram using the adm2582e/ADM2587E figure 40 is an example of a circuit diagram using the adm2582e/ADM2587E.
adm2582e/ADM2587E rev. 0 | page 19 of 20 typical applications figure 41 and figure 42 show typical applications of the adm2582e/ ADM2587E in half duplex and full duplex rs-485 network configurations. up to 256 transceivers can be connected to the rs-485 bus. to minimize reflections, terminate the line at the receiving end in its characteristic impedance, and keep stub lengths off the main line as short as possible. for half-duplex operation, this means that both ends of the line must be terminated because either end can be the receiving end. notes 1. r t is equal to the characteristic impedance of the cable. 2 . isolation not shown. abzy abzy a b z y a b z y r d r d r d r d adm2582e/ ADM2587E adm2582e/ ADM2587E adm2582e/ ADM2587E rxd re de txd rxd re de txd r t r t rxd re de txd rxd re de txd adm2582e/ ADM2587E maximum number of transceivers on bus = 256 08111-027 figure 41. adm2582e/ADM2587E typical half duplex rs-485 network notes 1. r t is equal to the characteristic impedance of the cable. 2. isolation not shown. r d a b z y r d a b z y r d a b z y r d a b z y r t txd de rxd re adm2582e/ ADM2587E adm2582e/ ADM2587E adm2582e/ ADM2587E slave rxd re de txd adm2582e/ ADM2587E master slave slave rxd re de txd rxd re de txd r t maximum number of nodes = 256 08111-028 figure 42. adm2582e/ADM2587E typical full duplex rs-485 network
adm2582e/ADM2587E rev. 0 | page 20 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-013-ac 13.00 (0.5118) 12.60 (0.4961) 0.30 (0.0118) 0.10 (0.0039) 2.65 (0.1043) 2.35 (0.0925) 10.65 (0.4193) 10.00 (0.3937) 7.60 (0.2992) 7.40 (0.2913) 0 . 7 5 ( 0 . 0 2 9 5 ) 0 . 2 5 ( 0 . 0 0 9 8 ) 1.27 (0.0500) 0.40 (0.0157) coplanarity 0.10 0.33 (0.0130) 0.20 (0.0079) 0.51 (0.0201) 0.31 (0.0122) seating plane 8 0 20 11 10 1 1.27 (0.0500) bsc 060706-a 45 figure 43. 20-lead standard small outline package [soic_w] wide body (rw-20) dimensions shown in millimeters and (inches) ordering guide model data rate (mbps) temperature rang e package description package option adm2582ebrwz 1 16 ?40c to +85c 20-lead soic_w rw-20 adm2582ebrwz-reel7 1 16 ?40c to +85c 20-lead soic_w rw-20 ADM2587Ebrwz 1 0.5 ?40c to +85c 20-lead soic_w rw-20 ADM2587Ebrwz-reel7 1 0.5 ?40c to +85c 20-lead soic_w rw-20 eval-adm2582eebz 1 adm2582e evaluation board eval-ADM2587Eebz 1 ADM2587E evaluation board 1 z = rohs compliant part. ?2009 analog devices, inc. all rights reserved. trademarks and registered trademarks are the prop erty of their respective owners. d08111-0-9/09(0)

▲Up To Search▲

Price & Availability of ADM2587E

	To Download ADM2587E Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .