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selector guide general description the MAX13442E/max13444e are fault-protected rs-485 and j1708 transceivers that feature 80v protection from signal faults on communication bus lines. the MAX13442E/max13444e feature a reduced slew-rate dri- ver that minimizes emi and reflections, allowing error-free transmission up to 250kbps. the max13443e driver can transmit up to 10mbps. the high-speed max13443e rs-485 tranceiver features ?0v protection from signal faults on communication bus lines. these transceivers fea- ture foldback current limit. each device contains one dif- ferential line driver with three-state output and one differential line receiver with three-state input. the 1/4-unit- load receiver input impedance allows up to 128 trans- ceivers on a single bus. the devices operate from a 5v supply. true fail-safe inputs guarantee a logic-high receiv- er output when the receiver inputs are open, shorted, or connected to an idle data line. hot-swap circuitry eliminates false transitions on the data bus during circuit initialization or connection to a live backplane. short-circuit current-limiting and ther- mal-shutdown circuitry protect the driver against exces- sive power dissipation, and on-chip 15kv esd protection eliminates costly external protection devices. the MAX13442E/max13443e/max13444e are avail- able in an 8-pin so package and are specified over the automotive temperature range. applications features ? 15kv esd protection ? 80v fault protection (60v max13443e) ? guaranteed 10mbps data rate (max13443e) ? hot-swappable for telecom applications ? true fail-safe receiver inputs ? enhanced slew-rate-limiting facilitates error-free data transmission (MAX13442E/max13444e) ? allow up to 128 transceivers on the bus ? -7v to +12v common-mode input range ? 6ma foldback current limit ? industry-standard pinout MAX13442E/max13443e/max13444e 15kv esd-protected, 80v fault-protected, fail-safe rs-485/j1708 transceivers ________________________________________________________________ maxim integrated products 1 top view 1 2 3 4 8 5 v cc gnd di de re ro r d r t r t 7 6 d r de re di ro a b 1 2 3 4 8 7 6 5 v cc b a gnd di de re ro so so r d b a MAX13442E max13443e + + pin configurations and typical operating circuits ordering information 19-3898; rev 3; 3/11 for pricing, delivery, and ordering information, please contact maxim direct at 1-888-629-4642, or visit maxim? website at www.maxim-ic.com. part temp range pin-package MAX13442E asa+ -40c to +125c 8 so max13443e asa+ -40c to +125c 8 so max13444e asa/v+t -40c to +125c 8 so part type data rate (mbps) fault protection (v) low-power shutdown receiver/driver enable transceivers on bus hot swap MAX13442E rs-485 0.25 ?0 yes yes 128 yes max13443e rs-485 10 ?0 yes yes 128 yes max13444e j1708 0.25 ?0 yes yes 128 yes (only re ) pin configurations and typical operating circuits continued at end of data sheet. rs-422/rs-485 communications truck and trailer applications industrial networks telecommunications systems automotive applications hvac controls + denotes a lead(pb)-free/rohs-compliant package. /v denotes an automotive qualified part. t = tape and reel. www.datasheet.co.kr datasheet pdf - http://www..net/
MAX13442E/max13443e/max13444e 15kv esd-protected, 80v fault-protected, fail-safe rs-485/j1708 transceivers 2 _______________________________________________________________________________________ absolute maximum ratings stresses beyond those listed under ?bsolute maximum ratings?may cause permanent damage to the device. these are stress rating s only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specificatio ns is not implied. exposure to absolute maximum rating conditions for extended periods may affect device reliability. (voltages referenced to gnd.) v cc ........................................................................................+7v re , de, de , di, txd ...................................-0.3v to (v cc + 0.3v) a, b (note 1) (MAX13442E/max13444e) ............................?0v a, b (note 1) (max13443e) .................................................?0v ro ..............................................................-0.3v to (v cc + 0.3v) short-circuit duration (ro, a, b) ...............................continuous continuous power dissipation (t a = +70?) so (derate 7.6mw/? above +70?) ...........................606mw operating temperature range .........................-40? to +125? storage temperature range .............................-65? to +150? junction temperature ......................................................+150? lead temperature (soldering, 10s) .................................+300? soldering temperature (reflow) .......................................+260? package thermal characteristics (note 2) so junction-to-ambient thermal resistance ( ja ) .........132?/w junction-to-case thermal resistance ( jc ) ................38?/w dc electrical characteristics (v cc = +4.75v to +5.25v, t a = t min to t max , unless otherwise noted. typical values are at v cc = +5v and t a = +25?.) parameter symbol conditions min typ max units driver figure 1, r l = 100 2 v cc differential driver output v od figure 1, r l = 54 1.5 v cc v change in magnitude of differential output voltage v od figure 1, r l = 100 or 54 (note 3) 0.2 v driver common-mode output voltage v oc figure 1, r l = 100 or 54 v cc / 2 3 v change in magnitude of common-mode voltage v oc figure 1, r l = 100 or 54 (note 3) (MAX13442E/max13443e) 0.2 v driver logic driver-input high voltage v dih 2 v driver-input low voltage v dil 0.8 v driver-input current i din 2 a 0v v out +12v +350 driver short-circuit output current (note 4) i osd -7v v out v cc -350 ma (v cc - 1v) v out +12v (note 4) +25 driver short-circuit foldback output current i osdf -7v v out +1v (note 4) -25 ma v out +20v, r l = 100 +6 driver-limit short-circuit foldback output current i osdl v out -15v, r l = 100 -6 ma note 1: during normal operation, a termination resistor must be connected between a and b in order to guarantee overvoltage pro- tection up to the absolute maximum rating of this device. when not in operation, these devices can withstand fault voltages up to the maximum rating without a termination resistor and will not be damaged. note 2: package thermal resistances were obtained using the method described in jedec specification jesd51-7, using a four- layer board. for detailed information on package thermal considerations, refer to www.maxim-ic.com/thermal-tutorial . www.datasheet.co.kr datasheet pdf - http://www..net/
MAX13442E/max13443e/max13444e 15kv esd-protected, 80v fault-protected, fail-safe rs-485/j1708 transceivers _______________________________________________________________________________________ 3 parameter symbol conditions min typ max units receiver v cc = gnd, v a, b = 12v 250 v a, b = -7v -150 a input current i a,b a, b receive mode v a, b = 80v 6 ma receiver-differential threshold voltage v th -7v v cm +12v -200 -50 mv receiver-input hysteresis v th 25 mv receiver logic output-high voltage v oh figure 2, i oh = -1.6ma v cc - 0.6 v output-low voltage v ol figure 2, i ol = 1ma 0.4 v three-state output current at receiver i ozr 0v v a, b v cc 1 a receiver input resistance r in -7v v cm +12v 48 k receiver output short-circuit current i osr 0v v ro v cc 95 ma control control-input high voltage v cih de, de , re 2 v input-current latch during first rising edge i in de, re 90 a supply current de = v cc , re = gnd (MAX13442E) ( de = re = gnd) (max13444e) 30 normal operation i cc no load, di = v cc or gnd (de = v cc , re = gnd) (max13443e) 10 ma de = gnd, re = v cc (MAX13442E/max13443e) 20 de = gnd, re = v cc , t a = +25c (MAX13442E/max13443e) 10 de = re = v cc (max13444e) 100 supply current in shutdown mode i shdn de = re = v cc , t a = +25c (max13444e) 10 a supply current with output shorted to 60v i shrt de = gnd, re = gnd, no load output in three-state (max13443e) 15 ma dc electrical characteristics (continued) (v cc = +4.75v to +5.25v, t a = t min to t max , unless otherwise noted. typical values are at v cc = +5v and t a = +25?.) www.datasheet.co.kr datasheet pdf - http://www..net/
MAX13442E/max13443e/max13444e 15kv esd-protected, 80v fault-protected, fail-safe rs-485/j1708 transceivers 4 _______________________________________________________________________________________ parameter symbol conditions min typ max units figure 3, r l = 54 , c l = 50pf (MAX13442E) driver propagation delay t plha, t plhb r diff = 60 , c diff = 100pf (max13444e) 2000 ns driver differential propagation delay t dplh , t dphl r l = 54 , c l = 50pf, figure 4 2000 ns driver differential output transition time t lh ,t hl r l = 54 , c l = 50pf, figure 4 200 2000 ns driver output skew t s kewab , t s kewba r l = 54 , c l = 50pf, t skewab = |t plha - t phlb |, t skewba = |t plhb - t phla | 350 ns differential driver output skew t dskew r l = 54 , c l = 50pf, t dskew = |t dplh - t dphl | 200 ns maximum data rate f max 250 kbps driver enable time to output high t pdzh r l = 500 , c l = 50pf, figure 5 2000 ns driver disable time from output high t pdhz r l = 500 , c l = 50pf, figure 5 2000 ns driver enable time from shutdown to output high t pdhs r l = 500 , c l = 50pf, figure 5 4.2 ? driver enable time to output low t pdzl r l = 500 , c l = 50pf, figure 6 2000 ns driver disable time from output low t pdlz r l = 500 , c l = 50pf, figure 6 2000 ns driver enable time from shutdown to output low t pdls r l = 500 , c l = 50pf, figure 6 4.2 ? driver time to shutdown t shdn r l = 500 , c l = 50p f 800 ns receiver propagation delay t rplh , t rphl c l = 20pf, v id = 2v, v cm = 0v, figure 7 2000 ns receiver output skew t rskew c l = 20pf, t rskew = |t rplh - t rphl | 200 ns receiver enable time to output high t rpzh r l = 1k , c l = 20pf, figure 8 2000 ns recei ver d i sab l e ti m e fr om outp ut h i g ht rphz r l = 1k , c l = 20pf, figure 8 2000 ns receiver wake time from shutdown t rpwake r l = 1k , c l = 20pf, figure 8 4.2 ? receiver enable time to output low t rpzl r l = 1k , c l = 20pf, figure 8 2000 ns recei ver d i sab l e ti m e fr om outp ut low t rplz r l = 1k , c l = 20pf, figure 8 2000 ns receiver time to shutdown t shdn r l = 500 , c l = 50pf 800 ns switching characteristics (MAX13442E/max13444e) (v cc = +4.75v to +5.25v, t a = t min to t max , unless otherwise noted. typical values are at v cc = +5v and t a = +25?.) parameter symbol conditions min typ max units MAX13442E/ max13444e 80 overvoltage protection a, b; r source = 0 , r l = 54 max13443e 60 v esd protection a, b human body model 15 kv protection specifications (v cc = +4.75v to +5.25v, t a = t min to t max , unless otherwise noted. typical values are at v cc = +5v and t a = +25?.) www.datasheet.co.kr datasheet pdf - http://www..net/
MAX13442E/max13443e/max13444e 15kv esd-protected, 80v fault-protected, fail-safe rs-485/j1708 transceivers _______________________________________________________________________________________ 5 parameter symbol conditions min typ max units driver propagation delay t plha, t plhb r l = 27 , c l = 50pf, figure 3 60 ns driver differential propagation delay t dplh , t dphl r l = 54 , c l = 50pf, figure 4 60 ns driver differential output transition time t lh ,t hl r l = 54 , c l = 50pf, figure 4 25 ns driver output skew t skewab , t skewba r l = 54 , c l = 50pf, t skewab = |t plha - t phlb |, t skewba = |t plhb - t phla | 10 ns differential driver output skew t dskew r l = 54 , c l = 50pf, t dskew = |t dplh - t dphl | 10 ns maximum data rate f max 10 mbps driver enable time to output high t pdzh r l = 500 , c l = 50pf, figure 5 1200 ns driver disable time from output high t pdhz r l = 500 , c l = 50pf, figure 5 1200 ns driver enable time from shutdown to output high t pdhs r l = 500 , c l = 50pf, figure 5 4.2 ? driver enable time to output low t pdzl r l = 500 , c l = 50pf, figure 6 1200 ns driver disable time from output low t pdlz r l = 500 , c l = 50pf, figure 6 1200 ns driver enable time from shutdown to output low t pdls r l = 500 , c l = 50pf, figure 6 4.2 ? driver time to shutdown t shdn r l = 500 , c l = 50p f, figure 6 800 ns receiver propagation delay t rplh , t rphl c l = 20pf, v id = 2v, v cm = 0v, figure 7 85 ns receiver output skew t rskew c l = 20pf, t rskew = |t rplh - t rphl |15ns receiver enable time to output high t rpzh r l = 1k , c l = 20pf, figure 8 400 ns recei ver d i sab l e ti m e fr om outp ut h i g ht rphz r l = 1k , c l = 20pf, figure 8 400 ns receiver wake time from shutdown t rpwake r l = 1k , c l = 20pf, figure 8 4.2 ? receiver enable wake time from shutdown t rpsh r l = 1k , c l = 20pf, figure 8 400 ns recei ver d i sab l e ti m e fr om outp ut low t rplz r l = 1k , c l = 20pf, figure 8 400 ns receiver time to shutdown t shdn r l = 500 , c l = 50pf 800 ns switching characteristics (max13443e) (v cc = +4.75v to +5.25v, t a = t min to t max , unless otherwise noted. typical values are at v cc = +5v and t a = +25?.) note 3: v od and v oc are the changes in v od and v oc , respectively, when the di input changes state. note 4: the short-circuit output current applies to peak current just before foldback current limiting. the short-circuit foldback out- put current applies during current limiting to allow a recovery from bus contention. www.datasheet.co.kr datasheet pdf - http://www..net/
MAX13442E/max13443e/max13444e 15kv esd-protected, 80v fault-protected, fail-safe rs-485/j1708 transceivers 6 _______________________________________________________________________________________ typical operating characteristics (v cc = +5v, t a = +25?, unless otherwise noted.) no-load supply current vs. temperature max13442-4e toc01 temperature ( c) supply current (ma) 110 95 80 65 50 35 20 5 -10 -25 1 2 3 4 5 6 0 -40 125 driver and receiver enabled max13443e driver disabled, receiver enabled no-load supply current vs. temperature max13442-4e toc02 temperature ( c) supply current (ma) 110 95 80 65 50 35 20 5 -10 -25 4 8 12 16 20 24 0 -40 125 driver and receiver enabled MAX13442E/max13444e driver disabled, receiver enabled shutdown supply current vs. temperature max13442-4e toc03 temperature ( c) shutdown supply current ( a) 120 100 80 60 40 20 0 -20 0.00001 0.0001 0.001 0.01 0.1 1 10 0.000001 -40 MAX13442E di = de = gnd re = v cc 0 10 5 15 30 35 25 20 40 0 1.0 1.5 2.0 2.5 0.5 3.0 3.5 4.0 4.5 5.0 receiver output current vs. output-low voltage max13442-4e toc04 output low voltage (v) receiver output current (ma) 0 10 5 15 30 35 25 20 40 0 1.0 1.5 2.0 2.5 0.5 3.0 3.5 4.0 4.5 5.0 receiver output current vs. output-high voltage max13442-4e toc05 output low voltage (v) receiver output current (ma) 0 1.0 0.5 2.5 2.0 1.5 3.0 3.5 4.5 4.0 5.0 -40 -10 5 -25 20 35 50 65 80 95 110 125 receiver output voltage vs. temperature max13442-4e toc06 temperature ( c) receiver output voltage (v) v ol , i out = -10ma v oh , i out = 10ma 0 40 20 80 60 140 120 100 10 30 20 40 50 60 70 80 driver output current vs. differential output voltage max13442-4e toc07 differential output voltage (v) driver output current (ma) MAX13442E di = gnd, de = v cc , voltage applied to output a r l = 54 www.datasheet.co.kr datasheet pdf - http://www..net/
MAX13442E/max13443e/max13444e 15kv esd-protected, 80v fault-protected, fail-safe rs-485/j1708 transceivers _______________________________________________________________________________________ 7 0 1.0 0.5 2.0 1.5 3.0 2.5 3.5 -40 -10 5 20 -25 35 50 65 80 95 110 125 differential output voltage vs. temperature max13442-4e toc10 temperature ( c) differential output voltage (v) rl = 100 rl = 54 max13443e -2000 -400 -1200 -1600 -800 1200 800 400 0 2800 2400 2000 1600 3200 a, b current vs. a, b voltage (to ground) max13442-4e toc11 a, b voltage (v) a, b current ( a) -80 -60 -40 0 -20 40 60 20 80 driver disabled, receiver enabled MAX13442E no load r l = 54 -2000 -1200 -1600 0 -400 -800 400 800 1600 1200 2000 -60 -40 -30 -50 -20 -10 0 10 20 30 40 60 50 a, b current vs. a, b voltage (to ground) max13442-4e toc12 a, b voltage (v) a, b current ( a) driver disabled, receiver enabled max13443e no load r l = 54 typical operating characteristics (continued) (v cc = +5v, t a = +25?, unless otherwise noted.) 0 30 20 10 40 50 60 70 80 90 100 -80 -50 -65 -35 -20 -5 driver output current vs. differential output voltage max13442-4e toc08 differential output voltage (v) driver output current (ma) MAX13442E di = gnd, de = v cc , voltage applied to output b r l = 54 0 1.0 0.5 2.0 1.5 3.0 2.5 3.5 -40 -10 5 20 -25 35 50 65 80 95 110 125 differential output voltage vs. temperature max13442-4e toc09 temperature ( c) differential output voltage (v) r l = 100 r l = 54 MAX13442E www.datasheet.co.kr datasheet pdf - http://www..net/
MAX13442E/max13443e/max13444e 15kv esd-protected, 80v fault-protected, fail-safe rs-485/j1708 transceivers 8 _______________________________________________________________________________________ v cc d v od v oc 2 r l 2 r l di a b figure 1. driver v od and v oc r ro 0 v oh i oh (-) i ol (+) v ol v id a b figure 2. receiver v oh and v ol v cc v om 3v 0v v oh v om v om v om v om v ol v oh v ol 50 r l c l = 50pf (note 6) generator (note 5) d di t plha 1.5v a b out s1 di 1.5v t phla t phlb t plhb 1.5v v oh + v ol 2 v om = a b 2 test circuits and waveforms v cc 50 r l c l = 50pf (note 6) generator (note 5) d di out c l c l t dplh t dphl t lh 50% 1.5v 10% (a?) di 90% 50% 1.5v 10% 90% 3v 0v 2.0v t hl -2.0v a b figure 4. driver differential output delay and transition times figure 3. driver propagation times www.datasheet.co.kr datasheet pdf - http://www..net/
MAX13442E/max13443e/max13444e 15kv esd-protected, 80v fault-protected, fail-safe rs-485/j1708 transceivers _______________________________________________________________________________________ 9 50 generator (note 5) c l = 20pf (note 6) v id r r o t rplh 1.0v ro 1.0v 0v (a?) 1.0v 2.0v 0v t rphl v cc v om v om 0v a b a, b de v cc 3v 0v v cc v ol v om t pdls 1.5v 0.25v 1.5v t pdlz 50 generator (note 5) d 0 or 3v a, b s1 c l = 50pf (note 6) r l = 500 di de a b t pdzl figure 6. driver enable and disable times figure 7. receiver propagation delay test circuits and waveforms (continued) 50 generator (note 5) 1.5v v oh + v ol 2 v om = 3v 0v v oh v om 0v d 0 or 3v t pdhs t pdhz 1.5v 0.25v a, b a, b s1 de 1.5v c l = 50pf (note 6) r l = 500 di a b de t pdzh figure 5. driver enable and disable times www.datasheet.co.kr datasheet pdf - http://www..net/
MAX13442E/max13443e/max13444e 15kv esd-protected, 80v fault-protected, fail-safe rs-485/j1708 transceivers 10 ______________________________________________________________________________________ 50 generator (note 5) c l = 20pf (note 6) v cc 3v 0v v cc v ol r +1.5v -1.5v v id 1.5v ro s1 s2 1k re 1.5v s1 closed s2 open v s3 = -1.5v t rpzl t rpsl 3v 0v v oh 0v 1.5v re 1.5v s1 open s2 closed v s3 = 1.5v t rpzh t rpsh t rpwake 3v 0v v cc v ol 0.5v ro re 1.5v s1 closed s2 open v s3 = -1.5v t rplz 3v 0v v oh 0v 0.5v 1.5v ro re s1 open s2 closed v s3 = 1.5v t rphz s3 r o a b ro figure 8. receiver enable and disable times test circuits and waveforms (continued) note 5: the input pulse is supplied by a generator with the following characteristics: f = 5mhz, 50% duty cycle; t r 6ns; z 0 = 50 . note 6: c l includes probe and stray capacitance. www.datasheet.co.kr datasheet pdf - http://www..net/
MAX13442E/max13443e/max13444e 15kv esd-protected, 80v fault-protected, fail-safe rs-485/j1708 transceivers ______________________________________________________________________________________ 11 pin description pin MAX13442E max13443e max13444e name function 1 1 ro receiver output. if the receiver is enabled and (v a - v b ) -50mv, ro = high; if (v a - v b ) -200mv, ro = low. 2 2 re receiver output enable. pull re low to enable ro. 3 de driver output enable. force de high to enable driver. pull de low to three-state the driver output. drive re high and pull de low to enter low-power shutdown mode. 4 di driver input. a logic-low on di forces the noninverting output low and the inverting output high. a logic-high on di forces the noninverting output high and the inverting output low. 5 5 gnd ground 6 6 a noninverting receiver input/driver output 7 7 b inverting receiver input/driver output 8 8 v cc positive supply, v cc = +4.75v to +5.25v. for normal operation, bypass v cc to gnd with a 0.1f ceramic capacitor. for full esd protection, bypass v cc to gnd with 1f ceramic capacitor. 3 de driver output enable. pull de low to enable the outputs. force de high to three-state the outputs. drive re and de high to enter low- power shutdown mode. 4 txd j1708 input. a logic-low on txd forces outputs a and b to the dominant state. a logic-high on txd forces outputs a and b to the recessive state. www.datasheet.co.kr datasheet pdf - http://www..net/
MAX13442E/max13443e/max13444e 15kv esd-protected, 80v fault-protected, fail-safe rs-485/j1708 transceivers 12 ______________________________________________________________________________________ receiving inputs outputs re de (v a - v b )ro 0 x -0.05v 1 0 x -0.2v 0 0 x open/shorted 1 1 1 x high-z 1 0 x shutdown table 3. MAX13442E/max13443e (rs-485/rs-422) x = don? care. receiving inputs outputs re de (v a - v b )ro 0 x -0.05v 1 0 x -0.2v 0 0 x open/shorted 1 1 0 x high-z 1 1 x shutdown table 4. max13444e (rs-485/rs-422) x = don? care. function tables transmitting inputs outputs re de di a b 0 0 x high-z high-z 01001 01110 1 0 x shutdown shutdown 11001 11110 table 1. MAX13442E/max13443e (rs-485/rs-422) x = don? care. transmitting inputs outputs conditions txd de ab 0 1 high-z high-z 1 1 high-z high-z 0 0 0 1 dominant state 1 0 high-z high-z recessive state table 2. max13444e (j1708) application www.datasheet.co.kr datasheet pdf - http://www..net/
MAX13442E/max13443e/max13444e 15kv esd-protected, 80v fault-protected, fail-safe rs-485/j1708 transceivers ______________________________________________________________________________________ 13 detailed description the MAX13442E/max13443e/max13444e fault-protect- ed transceivers for rs-485/rs-422 and j1708 communi- cation contain one driver and one receiver. these devices feature fail-safe circuitry, which guarantees a logic-high receiver output when the receiver inputs are open or shorted, or when they are connected to a termi- nated transmission line with all drivers disabled (see the true fail-safe section). all devices have a hot-swap input structure that prevents disturbances on the differential signal lines when a circuit board is plugged into a hot backplane (see the hot-swap capability section). the MAX13442E/max13444e feature a reduced slew-rate dri- ver that minimizes emi and reduces reflections caused by improperly terminated cables, allowing error-free data transmission up to 250kbps (see the reduced emi and reflections section). the max13443e driver is not slew- rate limited, allowing transmit speeds up to 10mbps. driver the driver accepts a single-ended, logic-level input (di) and transfers it to a differential, rs-485/rs-422 level output (a and b). deasserting the driver enable places the driver outputs (a and b) into a high-imped- ance state. receiver the receiver accepts a differential, rs-485/rs-422 level input (a and b), and transfers it to a single-ended, logic-level output (ro). deasserting the receiver enable places the receiver inputs (a and b) into a high-imped- ance state (see tables 1?). low-power shutdown the MAX13442E/max13443e/max13444e offer a low- power shutdown mode. force de low and re high to shut down the MAX13442E/max13443e. force de and re high to shut down the max13444e. a time delay of 50ns prevents the device from accidentally entering shutdown due to logic skews when switching between transmit and receive modes. holding de low and re high for at least 800ns guarantees that the MAX13442E/max13443e enter shutdown. in shutdown, the devices consume a maximum 20? supply current. 80v fault protection the driver outputs/receiver inputs of rs-485 devices in industrial network applications often experience voltage faults resulting from shorts to the power grid that exceed the -7v to +12v range specified in the eia/tia-485 stan- dard. in these applications, ordinary rs-485 devices (typical absolute maximum -8v to +12.5v) require costly external protection devices. to reduce system complexi- ty and eliminate this need for external protection, the dri- ver outputs/receiver inputs of the MAX13442E/ max13444e withstand voltage faults up to 80v (?0v for the max13443e) with respect to ground without dam- age. protection is guaranteed regardless whether the device is active, shut down, or without power. true fail-safe the MAX13442E/max13443e/max13444e use a -50mv to -200mv differential input threshold to ensure true fail-safe receiver inputs. this threshold guarantees the receiver outputs a logic-high for shorted, open, or idle data lines. the -50mv to -200mv threshold com- plies with the ?00mv threshold eia/tia-485 standard. 15kv esd protection as with all maxim devices, esd-protection structures are incorporated on all pins to protect against esd encountered during handling and assembly. the MAX13442E/max13443e/max13444e receiver inputs/ driver outputs (a, b) have extra protection against stat- ic electricity found in normal operation. maxim? engi- neers have developed state-of-the-art structures to protect these pins against ?5kv esd without damage. after an esd event, the MAX13442E/max13443e/ max13444e continue working without latchup. esd protection can be tested in several ways. the receiver inputs are characterized for protection to ?5kv using the human body model. esd test conditions esd performance depends on a number of conditions. contact maxim for a reliability report that documents test setup, methodology, and results. human body model figure 9a shows the human body model, and figure 9b shows the current waveform it generates when dis- charged into a low impedance. this model consists of a 100pf capacitor charged to the esd voltage of inter- est, which is then discharged into the device through a 1.5k resistor. driver output protection two mechanisms prevent excessive output current and power dissipation caused by faults or bus contention. the first, a foldback current limit on the driver output stage, provides immediate protection against short cir- cuits over the whole common-mode voltage range. the second, a thermal shutdown circuit, forces the driver out- puts into a high-impedance state if the die temperature exceeds +160?. normal operation resumes when the die temperature cools to +140?, resulting in a pulsed output during continuous short-circuit conditions. www.datasheet.co.kr datasheet pdf - http://www..net/
MAX13442E/max13443e/max13444e 15kv esd-protected, 80v fault-protected, fail-safe rs-485/j1708 transceivers 14 ______________________________________________________________________________________ v cc timer timer de (hot swap) 15 s 100 a m1 m2 5.6k 2ma figure 10. simplified structure of the driver enable pin (de) hot-swap capability hot-swap inputs inserting circuit boards into a hot, or powered, back- plane may cause voltage transients on de, re , and receiver inputs a and b that can lead to data errors. for example, upon initial circuit board insertion, the proces- sor undergoes a power-up sequence. during this period, the high-impedance state of the output drivers makes them unable to drive the MAX13442E/max13443e/ max13444e enable inputs to a defined logic level. meanwhile, leakage currents of up to 10? from the high-impedance output, or capacitively coupled noise from v cc or gnd, could cause an input to drift to an incorrect logic state. to prevent such a condition from occurring, the MAX13442E/max13443e/max13444e feature hot-swap input circuitry on de, and re to guard against unwanted driver activation during hot-swap sit- uations. the max13444e has hot-swap input circuitry only on re . when v cc rises, an internal pulldown (or pullup for re ) circuit holds de low for at least 10?, and until the current into de exceeds 200?. after the initial power-up sequence, the pulldown circuit becomes transparent, resetting the hot-swap tolerable input. hot-swap input circuitry at the driver-enable input (de), there are two nmos devices, m1 and m2 (figure 10). when v cc ramps from zero, an internal 15? timer turns on m2 and sets the sr latch, which also turns on m1. transistors m2, a 2ma current sink, and m1, a 100? current sink, pull de to gnd through a 5.6k resistor. m2 pulls de to the disabled state against an external parasitic capaci- tance up to 100pf that may drive de high. after 15?, the timer deactivates m2 while m1 remains on, holding de low against three-state leakage currents that may drive de high. m1 remains on until an external current source overcomes the required input current. at this time, the sr latch resets m1 and turns off. when m1 turns off, de reverts to a standard, high-impedance cmos input. whenever v cc drops below 1v, the input is reset. a complementary circuit for re uses two pmos devices to pull re to v cc . charge-current- limit resistor discharge resistance storage capacitor c s 100pf r c 1m r d 1.5k high- voltage dc source device under test figure 9a. human body esd test model i p 100% 90% 36.8% t rl time t dl current waveform peak-to-peak ringing (not drawn to scale) i r 10% 0 0 amperes figure 9b. human body model current waveform www.datasheet.co.kr datasheet pdf - http://www..net/
MAX13442E/max13443e/max13444e 15kv esd-protected, 80v fault-protected, fail-safe rs-485/j1708 transceivers ______________________________________________________________________________________ 15 applications information 128 transceivers on the bus the MAX13442E/max13443e/max13444e transceivers 1/4-unit-load receiver input impedance (48k ) allows up to 128 transceivers connected in parallel on one communication line. connect any combination of these devices, and/or other rs-485 devices, for a maximum of 32-unit loads to the line. reduced emi and reflections the MAX13442E/max13444e are slew-rate limited, minimizing emi and reducing reflections caused by improperly terminated cables. figure 11 shows the dri- ver output waveform and its fourier analysis of a 125khz signal transmitted by a max13443e. high-fre- quency harmonic components with large amplitudes are evident. figure 12 shows the same signal displayed for the MAX13442E transmitting under the same conditions. figure 12? high-frequency harmonic components are much lower in amplitude, compared with figure 11?, and the potential for emi is significantly reduced. in general, a transmitter? rise time relates directly to the length of an unterminated stub, which can be driven with only minor waveform reflections. the following equation expresses this relationship conservatively: length = t rise / (10 x 1.5ns/ft) where t rise is the transmitter? rise time. for example, the MAX13442E? rise time is typically 800ns, which results in excellent waveforms with a stub length up to 53ft. a system can work well with longer unterminated stubs, even with severe reflections, if the waveform settles out before the uart samples them. rs-485 applications the MAX13442E/max13443e/max13444e transceivers provide bidirectional data communications on multi- point bus transmission lines. figure 13 shows a typical network application circuit. the rs-485 standard cov- ers line lengths up to 4000ft. to minimize reflections and reduce data errors, terminate the signal line at both ends in its characteristic impedance, and keep stub lengths off the main line as short as possible. 5.00mhz 500khz/div 0 20db/div 2v/div figure 11. driver output waveform and fft plot of the max13443e transmitting a 125khz signal 5.00mhz 500khz/div 0 20db/div 2v/div figure 12. driver output waveform and fft plot of the MAX13442E transmitting a 125khz signal www.datasheet.co.kr datasheet pdf - http://www..net/
MAX13442E/max13443e/max13444e 15kv esd-protected, 80v fault-protected, fail-safe rs-485/j1708 transceivers 16 ______________________________________________________________________________________ j1708 applications the max13444e is designed for j1708 applications. to configure the max13444e, connect de and re to gnd. connect the signal to be transmitted to txd. terminate the bus with the load circuit as shown in figure 14. the drivers used by sae j1708 are used in a dominant- mode application. de is active low; a high input on de places the outputs in high impedance. when the driver is disabled (txd high or de high), the bus is pulled high by external bias resistors r1 and r2. therefore, a logic-level high is encoded as recessive. when all transceivers are idle in this configuration, all receivers output logic-high because of the pullup resistor on a and pulldown resistor on b. r1 and r2 provide the bias for the recessive state. c1 and c2 combine to form a lowpass filter, effective for reducing fm interference. r2, c1, r4, and c2 combine to form a 1.6mhz lowpass filter, effective for reducing am interference. because the bus is unterminated, at high frequencies, r3 and r4 perform a pseudotermina- tion. this makes the implementation more flexible, as no specific termination nodes are required at the ends of the bus. di ro de a b re ro ro ro di di di de de de d d d r r r bb b a a a 120 120 d r MAX13442E max13443e re re re figure 13. MAX13442E/max13443e typical rs-485 network www.datasheet.co.kr datasheet pdf - http://www..net/
MAX13442E/max13443e/max13444e r1 4.7k r3 47 c1 2.2nf c2 2.2nf r2 4.7k ro r x t x r4 47 j1708 bus a b txd d r de re max13444e v cc figure 14. j1708 application circuit (see tables 2 and 4) chip information process: bicmos package information for the latest package outline information and land patterns (footprints), go to www.maxim-ic.com/packages . note that a ?? ?? or ??in the package code indicates rohs status only. package drawings may show a different suffix character, but the drawing pertains to the package regardless of rohs status. 1 2 3 4 8 5 v cc gnd txd de re ro r d r t r t 7 6 d r de re txd ro a b 1 2 3 4 8 7 6 5 v cc b a gnd txd de re ro so so r d b a max13444e + + pin configurations and typical operating circuits (continued) 15kv esd-protected, 80v fault-protected, fail-safe rs-485/j1708 transceivers ______________________________________________________________________________________ 17 package type package code outline no. land pattern no. 8 so s8+4 21-0041 90-0096 www.datasheet.co.kr datasheet pdf - http://www..net/
MAX13442E/max13443e/max13444e 15kv esd-protected, 80v fault-protected, fail-safe rs-485/j1708 transceivers maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a maxim product. no circu it patent licenses are implied. maxim reserves the right to change the circuitry and specifications without notice at any time. 18 ____________________maxim integrated products, 120 san gabriel drive, sunnyvale, ca 94086 408-737-7600 2011 maxim integrated products maxim is a registered trademark of maxim integrated products, inc. revision history revision number revision date description pages changed 0 10/05 initial release 1 3/06 corrected the part numbers in the conditions for v oc in the dc electrical characteristics table; corrected the a, b current units from ma to a for the a, b current vs. a, b voltage (to ground) graphs in the typical operating characteristics section 2, 7 2 11/10 added lead(pb)-free parts to the ordering information table; added the soldering temperature to the absolute maximum ratings section; updated table 2 outputs 1, 2, 12 3 3/11 added an automotive qualified part to the ordering information ; added the package thermal characteristics section 1, 2 www.datasheet.co.kr datasheet pdf - http://www..net/

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