View ADM3491_1633895.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

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 which may result from its use. no license is granted by implication or otherwise under any patent or patent rights of analog devices. a ADM3491 one technology way, p.o. box 9106, norwood, ma 02062-9106, u.s.a. tel: 781/329-4700 world wide web site: http://www.analog.com fax: 781/326-8703 ? analog devices, inc., 1998 3.3 v, full duplex, 840 m a 20 mbps, eia rs-485 transceiver functional block diagram r d re de di a b z y ADM3491 ro features operates with +3.3 v supply eia rs-422 and rs-485 compliant over full cm range 19 k v input impedance up to 50 transceivers on bus 20 mbps data rate short circuit protection specified over full temperature range thermal shutdown interoperable with 5 v logic 840 m a supply current 2 na shutdown current also available in tssop package meets iec1000-4-4 (>1 kv) 8 ns skew upgrade for max 3491, sn75als180 applications telecommunications dte-dce interface packet switching local area networks data concentration data multiplexers integrated services digital network (isdn) appletalk industrial controls general description the ADM3491 is a low power differential line transceiver designed to operate using a single +3.3 v power supply. low power consumption coupled with a shutdown mode make it ideal for power sensitive applications. it is suitable for commu- nication on multipoint bus transmission lines. it is intended for balanced data transmission and complies with both eia standards rs-485 and rs-422. it contains a differen- tial line driver and a differential line receiver, making it suitable for full duplex data transfer. the input impedance is 19 k w allowing up to 50 transceivers to be connected on the bus. excessive power dissipation caused by bus contention or by output shorting is prevented by a thermal shutdown circuit. this feature forces the driver output into a high impedance state if, during fault conditions, a significant temperature increase is detected in the internal driver circuitry. the receiver contains a fail-safe feature that results in a logic high output state if the inputs are unconnected (floating). the ADM3491 is fabricated on bicmos, an advanced mixed technology process combining low power cmos with fast switching bipolar technology. the ADM3491 is fully specified over the industrial tem- perature range and is available in dip and soic packages as well as a new space saving tssop package.
C2C rev. 0 ADM3491Cspecifications (v cc = +3.3 v 6 0.3 v. all specifications t min to t max unless otherwise noted.) parameter min typ max units test conditions/comments driver differential output voltage, v od 2.0 v r l = 100 w , figure 1, v cc > 3.1 v 1.5 v r l = 54 w , figure 1 1.5 v r l = 60 w , figure 2, e7 v < v tst < +12 v d |v od | for complementary output states 0.2 v r = 54 w or 100 w , figure 1 common-mode output voltage v oc 3 v r = 54 w or 100 w , figure 1 d |v oc | for complementary output states 0.2 v r = 54 w or 100 w , figure 1 cmos input logic threshold low, v inl 0.8 v cmos input logic threshold high, v inh 2.0 v logic input current (de, di, re) 1.0 m a output leakage (y, z) current 3 m av o = e7 v or +12 v, v cc = 0 v or 3.6 v output short circuit current 250 ma v o = e7 v or +12 v receiver differential input threshold voltage, v th e0.2 +0.2 v e7 v < v cm < +12 v input voltage hysteresis, d v th 50 mv v cm = 0 v input resistance 12 19 k w e7 v < v cm < +12 v input current (a, b) +1 ma v in = +12 v e0.8 ma v in = e7 v logic enable input current ( re ) 1 m a output voltage low, v ol 0.4 v i out = +2.5 ma output voltage high, v oh v cc e0.4 v v i out = e1.5 ma short circuit output current 60 ma v out = gnd or v cc three-state output leakage current 1.0 m av cc = 3.6 v, 0 v < v out < v cc power supply current i cc outputs unloaded, 0.84 1.2 ma de = v cc , re = 0 v 0.84 1.2 ma de = 0 v, re = 0 v supply current in shutdown 0.002 1 m a de = 0 v, re = v cc specifications subject to change without notice.
ADM3491 C3C rev. 0 timing specifications parameter min typ max units test conditions/ comments driver differential output delay t dd 135nsr l = 60 w , c l1 = c l2 = 15 pf, figure 5 differential output transition time 1 8 15 ns r l = 60 w , c l1 = c l2 = 15 pf, figure 5 propagation delay input to output t plh , t phl 72235 nsr l = 27 w , c l1 = c l2 = 15 pf, figure 6 driver o/p to o/p t skew 8nsr l = 54 w , c l1 = c l2 = 15 pf, figure 6 enable/disable driver enable to output valid 45 90 ns r l = 110 w , c l = 50 pf, figure 3 driver disable timing 40 80 ns r l = 110 w , c l = 50 pf, figure 3 driver enable from shutdown 650 110 ns r l = 110 w , c l = 15 pf, figure 3 receiver time to shutdown 80 190 300 ns propagation delay input to output t plh , t phl 25 65 90 ns c l = 15 pf, figure 8 skew t plh Ct phl 10 ns c l = 15 pf, figure 8 receiver enable t en 25 50 ns c l = 15 pf, figure 4 receiver disable t den 25 45 ns c l = 15 pf, figure 4 receiver enable from shutdown 500 ns c l = 15 pf, figure 4 (v cc = +3.3 v, t a = +25 8 c) timing specifications parameter min typ max units test conditions/ comments driver differential output delay t dd 170nsr l = 60 w , c l1 = c l2 = 15 pf, figure 5 differential output transition time 2 8 15 ns r l = 60 w , c l1 = c l2 = 15 pf, figure 5 propagation delay input to output t plh , t phl 72270 nsr l = 27 w , c l1 = c l2 = 15 pf, figure 6 driver o/p to o/p t skew 10 ns r l = 54 w , c l1 = c l2 = 15 pf, figure 6 enable/disable driver enable to output valid 45 110 ns r l = 110 w , c l = 50 pf, figure 3 driver disable timing 40 110 ns r l = 110 w , c l = 50 pf, figure 3 driver enable from shutdown 650 110 ns r l = 110 w , c l = 15 pf, figure 3 receiver time to shutdown 50 190 500 ns propagation delay input to output t plh , t phl 25 65 115 ns c l = 15 pf, figure 8 skew t plh Ct phl 20 ns c l = 15 pf, figure 8 receiver enable t en 25 50 ns c l = 15 pf, figure 4 receiver disable t den 25 50 ns c l = 15 pf, figure 4 receiver enable from shutdown 600 ns c l = 15 pf, figure 4 (v cc = +3.3 v 6 0.3 v, t a = t min to t max )
ADM3491 C4C rev. 0 ordering guide model temperature range package description package options ADM3491an C40 c to +85 c plastic dip n-14 ADM3491ar C40 c to +85 c small outline (soic) r-14 ADM3491aru C40 c to +85 c thin shrink small outline (tssop) ru-16 absolute maximum ratings* (t a = +25 c unless otherwise noted) v cc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . +7 v inputs driver input (di) . . . . . . . . . . . . . . . .C0.3 v to v cc + 0.3 v control inputs (de, re ) . . . . . . . . . .C0.3 v to v cc + 0.3 v receiver inputs (a, b) . . . . . . . . . . . . . . . C7.5 v to +12.5 v outputs driver outputs . . . . . . . . . . . . . . . . . . . . . C7.5 v to +12.5 v receiver output . . . . . . . . . . . . . . . . . C0.5 v to v cc +0.5 v power dissipation 14-lead dip . . . . . . . . . . . . . . . . 800 mw q ja , thermal impedance . . . . . . . . . . . . . . . . . . . 140 c/w power dissipation 14-lead soic . . . . . . . . . . . . . . . 650 mw q ja , thermal impedance . . . . . . . . . . . . . . . . . . . 115 c/w power dissipation 16-lead tssop . . . . . . . . . . . . . . 500 mw q ja , thermal impedance . . . . . . . . . . . . . . . . . . . 158 c/w operating temperature range industrial (a version) . . . . . . . . . . . . . . . . C40 c to +85 c storage temperature range . . . . . . . . . . . . C65 c to +150 c lead temperature (soldering, 10 sec) . . . . . . . . . . . . +300 c vapor phase (60 sec) . . . . . . . . . . . . . . . . . . . . . . . . +215 c infrared (15 sec) . . . . . . . . . . . . . . . . . . . . . . . . . . .+220 c esd rating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . >2 kv eft rating (iec1000-4-4) . . . . . . . . . . . . . . . . . . . . . . >1 kv *stresses above those listed under absolute maximum ratings may cause perma- nent damage to the device. this is a stress rating only; functional operation of the device at these or any other conditions above those listed in the operational sections of this specification is not implied. exposure to absolute maximum ratings for extended periods of time may affect device reliability.
ADM3491 C5C rev. 0 pin configuration dip/soic 14 13 12 11 10 9 8 1 2 3 4 5 6 7 ADM3491 nc ro re de di gnd gnd top view (not to scale) v cc a b z y nc v cc nc = no connect tssop v cc nc ro re de di nc gnd nc a b nc z y nc nc 16 15 14 13 12 11 10 9 1 2 3 4 5 6 7 8 nc = no connect ADM3491 top view (not to scale) pin function descriptions mnemonic dip/ pin soic tssop function nc 1, 8 2, 7, 9, 10, 13, 16 no connect. ro 2 3 receiver output. high when a > b by 200 mv or low when a < b by 200 mv. re 3 4 receiver output enable. with re low, the receiver output ro is ena bled. with re high, the output goes high impedance. if re is high and de low, the ADM3491 enters a shutdown state. de 4 5 driver output enable. a high level enables the driver different ial outputs, y and z. a low level places it in a high impedance state. di 5 6 driver input. when the driver is e nabled, a logic low on di forces y low and z high while a logic high on di forces y high and z low. gnd 6, 7 8 ground connection, 0 v. y 9 11 noninverting driver output y. z 10 12 inverting driver output z. b 11 14 inverting receiver input b. a 12 15 noninverting receiver input a. v cc 13, 14 1 power supply, 3.3 v 0.3 v.
ADM3491 C6C rev. 0 test circuits v cc r/2 r/2 v oc v od figure 1. driver voltage measurement test circuit 0v or 3v de in de s1 r l c l v out v cc s2 figure 2. driver enable/disable test circuit di d rl diff c l1 c l2 v out figure 3. driver differential output delay test circuit di rl diff c l1 c l2 ro re a b r d figure 4. driver/receiver propagation delay test circuit r l 375 v 375 v v tst v od3 figure 5. driver voltage measurement test circuit 2 +1.5v C1.5v re in re c l s2 v out v cc s1 r l figure 6. receiver enable/disable test circuit de s1 in v cc c l v out r l v om figure 7. driver propagation delay test circuit re 0v 3v v id +1.5v c l v out figure 8. receiver propagation delay test circuit
ADM3491 C7C rev. 0 3v 0v z vo y vo 0v Cvo 1/2vo 90% point 10% point t r t skew t f 10% point 90% point 1.5v t phl 1.5v t plh t skew figure 9. driver propagation delay, rise/fall timing aCb ro 0v t plh 1.5v 0v v oh t phl v ol 1.5v figure 10. receiver propagation delay switching characteristics re r r 0v 1.5v o/p high o/p low v ol + 0.25v t hz v oh C 0.25v v ol v oh t zh t zl t lz 1.5v 1.5v 1.5v 0v 3v figure 11. driver enable/disable timing re r r 0v 1.5v o/p high o/p low v ol + 0.25v t hz v oh C 0.25v v ol v oh t zh t zl t lz 1.5v 1.5v 1.5v 0v 3v figure 12. receiver enable/disable timing
ADM3491 C8C rev. 0 output voltage C volts 14 0 0 3.5 0.5 1 1.5 2 2.5 3 12 8 6 4 2 10 output current C ma figure 13. receiver output low voltage vs. output current temperature C 8 c C40 100 C20 0 20406080 0.8 0 0.7 0.4 0.3 0.2 0.1 0.6 0.5 i ro = 2.5ma output voltage C v figure 14. receiver output low voltage vs. temperature differential o/p voltage C volts 120 0 03 0.5 1 1.5 2 2.5 100 80 60 40 20 output current C ma figure 15. driver differential output voltage vs. output current output high voltage C volts 14 0 04 0 1 1.5 2 2.5 3 3.5 12 8 6 4 2 10 .5 output current C ma figure 16. receiver output high voltage vs. output current temperature C 8 c 3.3 3 C40 100 C200 20406080 3.25 3.2 3.15 3.1 3.05 i ro = C1.5ma output voltage C v figure 17. receiver output high voltage vs. temperature temperature C 8 c 2.6 1.6 C40 100 C200 204060 80 2.5 2.0 1.9 1.8 1.7 2.3 2.1 2.4 2.2 output voltage C v figure 18. driver differential output voltage vs. temperature Ctypical performance characteristics
ADM3491 C9C rev. 0 temperature C 8 c 1.2 1.1 0.7 C40 100 C200 20406080 1 0.9 0.8 supply current C ma figure 19. supply current vs. temperature 3 2 1 t t t 4 t 100ft cable ch1 1.00v ch2 1.00v m40.0ns ch3 640mv ch3 2.00v ch4 2.00v [ t ] figure 20. driving 100 ft. cable l-h transition 3 2 1 t t t 4 t 100ft cat 5 cable ch1 1.00v ch2 1.00v m40.0ns ch3 640mv ch3 2.00v ch4 2.00v [ t ] figure 21. driving 100 ft. cable h-l transition temperature C 8 c 100 0 C40 80 C20 0 20 40 60 90 60 30 20 10 80 70 50 40 shutdown current C ma figure 22. shutdown current vs. temperature
ADM3491 C10C rev. 0 table i. transmitting truth table transmitting inputs outputs re de di z y x11 01 x10 10 0 0 x hi-z hi-z 1 0 x hi-z hi-z table ii. receiving truth table receiving inputs outputs re de aCb ro 0 x > +0.2 v 1 0 x < C0.2 v 0 0 x inputs o/c 1 1 x x hi-z re v cc ro r a b z y gnd de di ADM3491 rs-485/rs-422 link ADM3491 gnd re ro di de v cc y z a +3.3v 0.1 m f 0.1 m f +3.3v b d d r figure 23. ADM3491 full-duplex data link
ADM3491 C11C rev. 0 table iii. comparison of rs-422 and rs-485 interface standards specification rs-422 rs-485 transmission type differential differential maximum cable length 4000 ft. 4000 ft. minimum driver output voltage 2 v 1.5 v driver load impedance 100 w 54 w receiver input resistance 4 k w min 12 k w min receiver input sensitivity 200 mv 200 mv receiver input voltage range e7 v to +7 v e7 v to +12 v applications information differential data transmission differential data transmission is used to reliably transmit data at high rates over long distances and through noisy environments. differential transmission nullifies the effects of ground shifts and noise signals which appear as common-mode voltages on the line. two main standards are approved by the electronics industries association (eia) which specify the electrical characteristics of transceivers used in differential data transmission. the rs-422 standard specifies data rates up to 10 mbaud and line lengths up to 4000 ft. a single driver can drive a transmission line with up to 10 receivers. the rs-485 standard was defined to cater to true multipoint communications. this standard meets or exceeds all the re- quirements of rs-422, but also allows multiple drivers and receivers to be connected to a single bus. an extended common mode range of C7 v to +12 v is defined. the most significant difference between rs-422 and rs-485 is the fact that the drivers may be disabled thereby allowing more than one to be connected to a single line. only one driver should be enabled at a time, but the rs-485 standard contains addi- tional specifications to guarantee device safety in the event of line contention. cable and data rate the transmission line of choice for rs-485 communications is a twisted pair. twisted pair cable tends to cancel common-mode noise and also causes cancellation of the magnetic fields gener- ated by the current flowing through each wire, thereby reducing the effective inductance of the pair. the ADM3491 is designed for bidirectional data communica- tions on multipoint transmission lines. a typical application showing a multipoint transmission network is illustrated in figure 23. only one driver can transmit at a part icular time, but multiple receivers may be enabled simultaneously. as with any transmission line, it is important that reflections are minimized. this may be achieved by terminating the extreme ends of the line using resistors equal to the characteristic im- pedance of the line. stub lengths of the main line should also be kept as short as possible. a properly terminated transmission line appears purely resistive to the driver. receiver open-circuit fail safe the receiver input includes a fail-safe feature that guarantees a logic high on the receiver when the inputs are open circuit or floating.
ADM3491 C12C rev. 0 c3216C8C1/98 printed in u.s.a. outline dimensions dimensions shown in inches and (mm). 14-lead plastic dip (n-14) 14 17 8 0.795 (20.19) 0.725 (18.42) 0.280 (7.11) 0.240 (6.10) pin 1 0.325 (8.25) 0.300 (7.62) 0.015 (0.381) 0.008 (0.204) 0.195 (4.95) 0.115 (2.93) seating plane 0.022 (0.558) 0.014 (0.356) 0.060 (1.52) 0.015 (0.38) 0.210 (5.33) max 0.130 (3.30) min 0.070 (1.77) 0.045 (1.15) 0.100 (2.54) bsc 0.160 (4.06) 0.115 (2.93) 14-lead narrow body small outline (soic) (r-14) 14 8 7 1 0.3444 (8.75) 0.3367 (8.55) 0.2440 (6.20) 0.2284 (5.80) 0.1574 (4.00) 0.1497 (3.80) pin 1 seating plane 0.0098 (0.25) 0.0040 (0.10) 0.0192 (0.49) 0.0138 (0.35) 0.0688 (1.75) 0.0532 (1.35) 0.0500 (1.27) bsc 0.0099 (0.25) 0.0075 (0.19) 0.0500 (1.27) 0.0160 (0.41) 8 0 0.0196 (0.50) 0.0099 (0.25) x 45 16-lead thin shrink small outline (tssop) (ru-16) 16 9 8 1 0.201 (5.10) 0.193 (4.90) 0.256 (6.50) 0.246 (6.25) 0.177 (4.50) 0.169 (4.30) pin 1 seating plane 0.006 (0.15) 0.002 (0.05) 0.0118 (0.30) 0.0075 (0.19) 0.0256 (0.65) bsc 0.0433 (1.10) max 0.0079 (0.20) 0.0035 (0.090) 0.028 (0.70) 0.020 (0.50) 8 0

▲Up To Search▲

Price & Availability of ADM3491

	To Download ADM3491 Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .