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_______________________________________________________________ maxim integrated products 1 for pricing, delivery, and ordering information, please contact maxim direct at 1-888-629-4642, or visit maxims website at www.maxim-ic.com. rs-485 transceivers with integrated 100 ? /120 ? termination resistors max13450e/MAX13451E 19-5254; rev 0; 4/10 general description the max13450e/MAX13451E are half-duplex and full- duplex rs-485/rs-422 transceivers. these devices fea - ture internal 100 i and 120 i termination resistors. the resistor values are pin selectable. a logic supply input allows interfacing to logic levels down to +1.8v. the max13450e/MAX13451E feature strong drivers specified to drive low-impedance lines found when a fully loaded bus, based on todays 100 i characteristic impedance cable, is doubly terminated. both devices allow slew-rate limiting of the driver output to reduce emi and reflections for data rates up to 500kbps. the MAX13451E has a fault alarm indication output to signal to the system that an error condition exists in the driver. the MAX13451E also features a logic inversion function. the logic inversion allows phase reversal of the a-b signals in case these are inadvertently connected wrongly. the max13450e/MAX13451E have 1/8-unit load receiver input impedance, allowing up to 256 transceivers on the bus. all driver outputs are protected to q 30kv esd using the human body model (hbm). the max13450e/MAX13451E are available in a 14-pin tssop package and operate over the automotive -40 n c to +125 n c temperature range. applications industrial control systems portable industrial equipment motor control security networks medical networks ordering information/ selector guide features s 100 i /120 i pin-selectable internal termination resistors s driver drives 100 i double termination s 20mbps (max) data rate s pin-selectable slew-rate limiting s logic supply input allows interfacing down to 1.8v s driver fault-indication output (MAX13451E) s inverting of a, b line polarity (MAX13451E) s high-impedance driver output/receiver input when v cc supply is removed s hot-swap input structure on de, re, and term s extended esd protection 30kv human body model 15kv air gap discharge per iec 61000-4-2 7kv contact discharge per iec 61000-4-2 s 1/8-unit load allows up to 256 transceivers on the bus s thermal and overcurrent protected s fail-safe receivers s +4.5v to +5.5v supply voltage range functional diagram (MAX13451E) note: all devices are specified over the -40c to +125c operating temperature range. + denotes a lead(pb)-free/rohs-compliant package. * ep = exposed pad. MAX13451E d logic-level translation logic srl inv di fault de term b a re ro term100 gnd v l v cc part half/full duplex pin-package max13450e aud+ full 14 tssop-ep* MAX13451E aud+ half 14 tssop-ep*
rs-485 transceivers with integrated 100 ? /120 ? termination resistors max13450e/MAX13451E 2 ______________________________________________________________________________________ stresses beyond those listed under absolute maximum ratings may cause permanent damage to the device. these are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. exposure to absolute maximum rating conditions for extended periods may affect device reliability. (all voltages referenced to gnd.) v cc , v l ................................................................... -0.3v to +6v de, re , di, ro, term , term100, srl ..... -0.3v to (v l + 0.3v) inv, fault ................................................. -0.3v to (v l + 0.3v) a, b, z, y .................................................................. -8v to +13v a to b (high-z state) ......................................................... +14v b to a (high-z state) ......................................................... +14v short-circuit duration (ro, y, z) to gnd ................ continuous continuous power dissipation (t a = +70 n c) 14-pin tssop (derate 25.6mw/ n c above +70 n c) ..... 2051mw package junction-to-ambient thermal resistance ( b ja ) (note 1) ........................................... 39 n c/w package junction-to-case thermal resistance ( b jc ) (note 1) .............................................. 3 n c/w operating temperature range ....................... -40 n c to +125 n c storage temperature range .......................... -65 n c to +150 n c junction temperature .................................................... +150 n c lead temperature (soldering, 10s) ............................... +300 n c soldering temperature (reflow) ...................................... +260 n c electrical characteristics (v cc = +4.5v to +5.5v, v l = +1.62v to 4.2v, t a = t min to t max , unless otherwise noted. typical values are at v cc = +5v, v l = +1.8v, and t a = +25 n c.) (note 2) absolute maximum ratings note 1: 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 . parameter symbol conditions min typ max units supply voltage v cc 4.5 5.5 v logic supply voltage v l 1.62 1.8 4.2 v supply current i cc de = re = high, term = high, no load 6 ma de = re = low, term = low, no load 12 logic supply current i l current into v l , no load on ro, device not switching, de = re = high 2 f a shutdown current i shdn current into v cc , de = low, re = term = high 30 f a current into v cc , de = low, re = high, term = low 8 ma driver differential driver output v od r diff = 100 i , figure 1 (note 3) 2.0 v cc v r diff = 46 i , figure 1 (note 3) 1.5 v cc change in magnitude of differential output voltage d v od r diff = 100 i or 46 i , figure 1 (note 3) 0.2 v driver common-mode output voltage v oc r diff = 100 i or 46 i , figure 1 (note 3) v cc /2 3 v change in magnitude of common-mode voltage d v oc r diff = 100 i or 46 i , figure 1 (note 3) 0.2 v driver short-circuit output current i osd 0v p v out p +12v +280 ma -7v p v out p 0v -250 driver short-circuit foldback output current i osdf (v cc - 1v) p v out p +12v +15 ma -7v p v out p 0v -15
rs-485 transceivers with integrated 100 ? /120 ? termination resistors max13450e/MAX13451E _______________________________________________________________________________________ 3 electrical characteristics (continued) (v cc = +4.5v to +5.5v, v l = +1.62v to 4.2v, t a = t min to t max , unless otherwise noted. typical values are at v cc = +5v, v l = +1.8v, and t a = +25 n c.) (note 2) parameter symbol conditions min typ max units receiver input current (a and b) i a, b de = re = gnd; term = v l ; v cc = gnd or 5.5v v a or v b = +12v 125 f a v a or v b = -7v -100 receiver differential threshold voltage v th -7v p v cm p +12v, de = re = gnd; term = v l ; v cc = gnd v a or v b = +12v -200 -50 mv receiver input hysteresis d v th v a + v b = 0v 15 mv logic interface input high voltage v ih di, de, re , term , srl, term100, inv 2/3 x v l v input low voltage v il di, de, re , term , srl, term100, inv 1/3 x v l v input current i in di, de, re , term , term100, srl, inv -1 +1 f a receiver output high voltage v roh i out = -1ma v l - 0.6 v receiver output low voltage v rol i out = +1ma 0.4 v three-state output current at receiver i ozr 0v p v ro p v l -1 +0.01 +1 f a receiver output short-circuit current i osr 0v p v ro p v l q 1 q 80 ma fault output high voltage (MAX13451E) v faulth fault condition, i out = -1ma v l - 0.6 v fault output low voltage (MAX13451E) v faultl nonfault condition; i out = +1ma 0.4 v termination resistor 100 i termination resistor r 100 term = low, term100 = high 85 100 115 i 120 i termination resistor r 120 term = low, term100 = low 101 120 139 i single-ended input capacitance vs. gnd c in f = 1mhz (MAX13451E only) 40 pf esd protection esd protection (a, b, y, z) human body model q 30 kv iec 61000-4-2 air gap discharge q 15 iec 61000-4-2 contact discharge q 7 esd protection (all other pins) human body model q 2
rs-485 transceivers with integrated 100 ? /120 ? termination resistors max13450e/MAX13451E 4 ______________________________________________________________________________________ switching characteristicssrl = high (v cc = +4.5v to +5.5v, v l = +1.62v to 4.2v, t a = t min to t max , unless otherwise noted. typical values are at v cc = +5v, v l = +1.8v and t a = +25 n c.) (note 2) parameter symbol conditions min typ max units driver driver propagation delay t dplh r diff = 54 i , c l = 50pf, figures 2 and 3 800 ns t dphl 800 differential driver output skew |t dplh - t dphl | t dskew r diff = 54 i , c l = 50pf, figure 3 100 ns driver differential output rise or fall time t hl r diff = 54 i , c l = 50pf, figures 2 and 3 100 600 ns t lh 100 600 maximum data rate dr max 500 kbps driver enable from shutdown to output high t dzh(shdn) s2 closed, r l = 500 i , c l = 100pf, figures 4 and 5 4500 ns driver enable from shutdown to output low t dzl(shdn) s1 closed, r l = 500 i , c l = 100pf, figures 4 and 5 5200 ns driver disable delay t dlz , t dhz figures 4 and 5 100 ns driver enable delay t dzl , t dzh figures 4 and 5 2500 ns receiver receiver propagation delay t rplh c l = 15pf, |v id | r 2.0v; t lh , t hl p 15ns, figures 6 and 7 200 ns t rphl 200 receiver output skew t rskew c l = 15pf, figures 6 and 7 30 ns maximum data rate dr max 500 kbps receiver enable to output high t rzh s2 closed, c l = 100pf, r l = 500 i , figures 8 and 9 50 ns receiver enable to output low t rzl s1 closed, c l = 100pf, r l = 500 i , figures 8 and 9 50 ns receiver disable from high t rhz figures 8 and 9 50 ns receiver disable from low t rlz figures 8 and 9 50 ns receiver enable from shutdown to output high t rzh(shdn) figures 8 and 9 5000 ns receiver enable from shutdown to output low t rzl(shdn) figures 8 and 9 5000 ns termination resistor turn-off time t rtz figure 10 120 f s turn-on time t rten figure 10 1 f s
rs-485 transceivers with integrated 100 ? /120 ? termination resistors max13450e/MAX13451E _______________________________________________________________________________________ 5 switching characteristicssrl = low (v cc = +4.5v to +5.5v, v l = +1.62v to 4.2v, t a = t min to t max , unless otherwise noted. typical values are at v cc = +5v, v l = +1.8v, and t a = +25 n c.) (note 2) note 2: all devices are 100% production tested at t a = +25c. limits over temperature are guaranteed by design. note 3: termination resistance is disabled ( term = high). parameter symbol conditions min typ max units driver driver propagation delay t dplh r diff = 54 i , c l = 50pf, figures 2 and 3 50 ns t dphl 50 differential driver output skew |t dplh - t dphl | t dskew r diff = 54 i , c l = 50pf, figure 3 6 ns driver differential output rise or fall time t hl , t lh r diff = 54 i , c l = 50pf, figures 2 and 3 15 ns maximum data rate dr max 20 mbps driver enable from shutdown to output high t dzh(shdn) s2 closed, r l = 500 i , c l = 100pf, figures 4 and 5 2000 ns driver enable from shutdown to output low t dzl(shdn) s1 closed, r l = 500 i , c l = 100pf, figures 4 and 5 2000 ns driver disable delay t dlz , t dhz figures 4 and 5 100 ns driver enable delay t dzl , t dzh figures 4 and 5 100 ns receiver receiver propagation delay t rplh c l = 15pf, |v id | r 2.0v; t lh , t hl p 15ns, figures 6 and 7 50 ns t rphl 50 receiver output skew t rskew c l = 15pf, figures 6 and 7 6 ns maximum data rate dr max 20 mbps receiver enable to output high t rzh s2 closed, c l = 100pf, r l = 500 i , figures 8 and 9 50 ns receiver enable to output low t rzl s1 closed, c l = 100pf, r l = 500 i , figures 8 and 9 50 ns receiver disable time from high t rhz figures 8 and 9 50 ns receiver disable time from low t rlz figures 8 and 9 50 ns receiver enable from shutdown to output high t rzh(shdn) figures 8 and 9 2000 ns receiver enable from shutdown to output low t rzl(shdn) figures 8 and 9 2000 ns termination resistor turn-off time t rtz figure 10 120 f s turn-on time t rten figure 10 1 f s
rs-485 transceivers with integrated 100 ? /120 ? termination resistors max13450e/MAX13451E 6 ______________________________________________________________________________________ typical operating characteristics (v cc = +5v, v l = +1.8v, t a = +25 n c, unless otherwise noted.) driver differential output current vs. differential output voltage max13450e/51e toc07 driver differential output voltage (v) driver differential output current (ma) 4 3 2 1 20 40 60 80 100 0 0 5 receiver propagation delay vs. temperature max13450e/51e toc06 temperature (c) receiver propagation delay (ns) 110 95 80 65 50 35 20 5 -10 -25 20 40 60 80 100 0 -40 125 inv = high inv = low receiver output low voltage vs. temperature max13450e/51e toc05 temperature (c) receiver output low voltage (v) 110 95 80 65 50 35 20 5 -10 -25 0.1 0.2 0.3 0.4 0.5 0 -40 125 i out = 1ma receiver output high voltage vs. temperature max13450e/51e toc04 temperature (c) receiver output high voltage (v) 110 95 80 65 50 35 20 5 -10 -25 1.2 1.4 1.6 1.8 2.0 1.0 -40 125 i out = 1ma receiver output voltage vs. output current max13450e/51e toc03 output current (ma) receiver output voltage (v) 60 50 40 30 20 10 1 2 3 4 5 0 0 70 source sink shutdown current vs. temperature max13450e/51e toc02 temperature (c) shutdown current (a) 110 95 65 80 -10 5 20 35 50 -25 1 2 3 4 5 6 7 8 9 10 0 -40 125 supply current vs. data rate max13450e/51e toc01 data rate (mbps) supply current (ma) 10 1 10 20 30 40 50 60 70 0 0.1 100 r l = 54? r l = 100? no load transmitter output current vs. transmitter output low voltage max13450e/51e toc09 transmitter output low voltage (v) transmitter output current (ma) 7 2 20 40 60 80 100 120 140 160 180 200 0 -3 12 transmitter output current vs. transmitter output high voltage max13450e/51e toc08 transmitter output high voltage (v) transmitter output current (ma) 3 -2 20 40 60 80 100 120 0 -7
rs-485 transceivers with integrated 100 ? /120 ? termination resistors max13450e/MAX13451E _______________________________________________________________________________________ 7 typical operating characteristics (continued) (v cc = +5v, v l = +1.8v, t a = +25 n c, unless otherwise noted.) 100? termination resistor vs. frequency frequency (mhz) magnitude (?) phase (degree) 10 1 20 40 60 80 100 120 140 0 0.1 100 0 -10 -20 -30 max13450e/51e toc11 r 100 magnitude r 100 phase 120? termination resistor vs. frequency frequency (mhz) magnitude (?) phase (degree) 10 1 20 40 60 80 100 120 140 0 0.1 100 0 -10 -20 -30 max13450e/51e toc12 r 120 magnitude r 120 phase driver differential output voltage vs. temperature max13450e/51e toc10 temperature (c) driver differential output voltage (v) 110 95 80 65 50 35 20 5 -10 -25 1 2 3 4 5 0 -40 125 r diff = 54? termination resistance vs. temperature max13450e/51e toc13 temperature (c) termination resistance ( ? ) 110 95 80 65 50 35 20 5 -10 -25 90 100 110 120 130 80 -40 125 120? resistor 100? resistor driver propagation delay (250kbps) (MAX13451E) max13450e/51e toc14 1s/div di 1v/div a 1v/div b 1v/div srl = high de = high re = high driver enable time from shutdown (MAX13451E) max13450e/51e toc15 200ns/div de 2v/div a 2v/div b 2v/div srl = low re = high
rs-485 transceivers with integrated 100 ? /120 ? termination resistors max13450e/MAX13451E 8 ______________________________________________________________________________________ test circuits and waveforms figure 1. driver dc test load figure 3. driver propagation delays figure 2. driver timing test circuit v oc a/y b/z r diff 2 r diff v od c l 2 a b de di v l r diff c l v id v l /2 v l /2 0v di b a t dplh t dphl 1/2 v o 1/2 v o v o 10% 90% 10% 90% 0v v o -v o v dd t dskew = |t dplh - t dphl | t hl t lh v l f = 1mhz, t lh 3ns, t hl 3ns
rs-485 transceivers with integrated 100 ? /120 ? termination resistors max13450e/MAX13451E _______________________________________________________________________________________ 9 test circuits and waveforms (continued) figure 5. driver-enable and disable-timing test load figure 4. driver enable and disable times figure 7. receiver propagation delays figure 6. receiver propagation delay test circuit v l /2 v l /2 v cc v oh 0v 0v output normally low de output normally high t dzl(shdn) ,t dzl t dzh(shdn) ,t dzh t dlz t dhz (v cc + v ol )/2 v oh /2 v ol + 0.25v v oh - 0.25v a/y, b/z a/y, b/z v ol v l output under test 500 ? s1 s2 v cc c l ate v id a b r receiver output v l /2 v l /2 1v -1v f = 1mhz, t lh 3ns, t hl 3ns t rphl t rplh v roh v rol ro a b t rskew = |t rphl - t rplh |
rs-485 transceivers with integrated 100 ? /120 ? termination resistors max13450e/MAX13451E 10 _____________________________________________________________________________________ test circuits and waveforms (continued) figure 8. receiver enable and disable times figure 9. receiver enable and disable times figure 10. termination resistor turn-on/-off times v l /2 v l /2 ro 0v 0v output normally low ro output normally high t rzh(shdn) , t rzh t rhz t rhz (v l + v rol )/2 v roh /2 r oh - 0.25v r oh + 0.25v di = 0v re v l v l v roh v rol t rzl(shdn) , t rzl ro 500 ? s1 s2 v cc c l 90% 10% 0v v ab = v a - v b r d = r 100 or r 200 v l v l /2 t ren t ren i a receiver ro term b i a = v ab /r d a term
rs-485 transceivers with integrated 100 ? /120 ? termination resistors max13450e/MAX13451E ______________________________________________________________________________________ 11 pin configurations pin description + top view tssop 11 4 gnd v cc 12 3 z di 13 2 term100 re 14 1 srl de 8 7 a ro 9 6 b v l 10 5 y term ep max13450e + top view tssop 11 4 gnd v cc 12 3 b di 13 2 term100 re 14 1 srl de 8 7 inv ro 9 6 fault v l 10 5 a term ep MAX13451E pin name function max13450e MAX13451E 1 1 de driver-output enable. drive de low to put the driver output in three-state. drive de high to enable the driver. de is referenced to v l . 2 2 re receiver-output enable. drive re low to enable the ro. drive re high to disable the ro output and put the ro output in a high-impedance state. re is referenced to v l . 3 3 di driver input. drive di low to force the noninverting output low and the inverting output high. drive di high to force the noninverting output high and inverting out - put low. di is referenced to v l . 4 4 v cc power-supply voltage. bypass v cc to gnd with a 0.1 f f ceramic capacitor placed as close as possible to the device. 5 5 term active-low termination resistor enable. drive term low to enable the internal ter - mination resistor. term is referenced to v l . 6 6 v l logic supply voltage. bypass v l to gnd with a 0.1 f f ceramic capacitor placed as close as possible to the device. 7 ro receiver output. when receiver is enabled and v a - v b r -50mv, ro is high. if v a - v b p -200mv, ro is low. ro is referenced to v l . 7 ro receiver output. when inv is low, receiver is enabled and v a - v b r -50mv, ro is high. if v a - v b p -200mv, ro is low. when inv is high, receiver is enabled and v a - v b r -50mv, ro is low. if v a - v b p -200mv, ro is high. ro is referenced to v l . 8 a noninverting receiver input 10 a if inv is low, a is a noninverting receiver input and a noninverting driver output. if inv is high, a is an inverting receiver input and an inverting driver output. 9 b inverting receiver input 12 b if inv is low, b is an inverting receiver input and an inverting driver output. if inv is high, b is a noninverting receiver input and a noninverting driver output.
rs-485 transceivers with integrated 100 ? /120 ? termination resistors max13450e/MAX13451E 12 _____________________________________________________________________________________ pin description (continued) function tables table 1. termination resistor control (max13450e/MAX13451E) table 4. function table for receiver (max13450e) table 5. inv input function table for transmitter (MAX13451E) table 2. shutdown control (max13450e/ MAX13451E) table 3. function table for transmitter (max13450e) pin name function max13450e MAX13451E 10 y noninverting driver output 11 11 gnd ground 12 z inverting driver output 13 13 term100 termination resistor value selection input. drive term100 low to select a 120 i termination and high to select a 100 i termination. the term100 input is refer - enced to v l . 14 14 srl slew-rate limiting-enable input. drive srl high to enable slew-rate limiting and low to disable slew-rate limiting. the srl input is referenced to v l . 8 inv inversion input. drive inv high to internally swap ro logic level with respect to a and b signals. 9 fault fault flag output. fault asserts high in overcurrent conditions or if a/b are forced below gnd or above v cc when the driver is enabled. fault is referenced to v l . ep exposed pad term de re termination resistor low x x activated high x x not activated de re term state low high high shutdown input output de di y z low x high-z high-z high low low high high high low input output re a-b ro high x high-z low r -50mv or open high p -200mv low input output de inv di a b low x x high-z high-z high low low low high high high low high low high low high low high
rs-485 transceivers with integrated 100 ? /120 ? termination resistors max13450e/MAX13451E ______________________________________________________________________________________ 13 detailed description the max13450e is a full-duplex, rs-485/rs-422- compatible transceiver and the MAX13451E is a half- duplex, rs-485/rs-422-compatible transceiver. both devices have an internal 100 i /120 i termination resistor. the max13450e/MAX13451E have a v l supply voltage input to support down to a +1.8v voltage logic interface. the max13450e/MAX13451E feature a 1/8-unit load receiver input impedance, allowing up to 256 transceiv - ers on the bus. all line interface pins are protected to q 30kv esd based on the hbm. these devices also include fail-safe circuitry, guaranteeing a defined logic- level receiver output when the receiver inputs are open or shorted. the max13450e/MAX13451E allow slew-rate-limited driver outputs for lower data rates below 500kbps. the srl reduces the slew rate, which reduces emi emissions and reflections caused by improperly terminated cables. the MAX13451E has a fault output that indicates a fault condition on the driver. the MAX13451E also has an inv input that inverts the phase of a and b pins. termination resistor the max13450e/MAX13451E feat ure a selectable inter - nal termination resistor. drive the term input low to enable the internal termination resistor. drive the term input high to disable the internal termination resistor. drive the term100 input high to select the 100 i termi - nation resistor. drive term100 input low to select the 120 i termination resistor. inv input (MAX13451E) the inv input of the MAX13451E reverses the polarity of the ro receiver output (see table 5 and 6). if the inv input is high then the ro output is low under fail-safe receiver conditions. this is the opposite polarity of nor - mal fail-safe operations. fault condition (MAX13451E) the MAX13451E also has a fault output to indicate a fault condition. the fault output is active high when there is a short circuit at the drivers output, an over/ undervoltage at the drivers outputs, or the devices tem - perature is higher than +150 n c. table 6. inv input function table for receiver (MAX13451E) function tables (continued) functional diagram (max13450e) max13450e d logic-level translation srl di de term z y a b re ro term100 gnd v l v cc input output re inv a-b ro high x x high-z low low r -50mv or short or open high p -200mv low high r -50mv or open low p -200mv high
rs-485 transceivers with integrated 100 ? /120 ? termination resistors max13450e/MAX13451E 14 _____________________________________________________________________________________ thermal shutdown when the devices temperature goes over +150 n c, the termination resistor turns off, and the transmitter shuts down while the receiver stays active. fail safe the max13450e guarantee a logic-high receiver output when the receiver inputs are shorted or open, or when they are connected to a terminated transmission line with all drivers disabled. this is done by setting the receiver input threshold between -50mv and -200mv. if the dif - ferential receiver input voltage (a - b) is greater than or equal to -50mv, ro is logic-high. if (a - b) is less than or equal to -200mv, ro is logic-low. in the case of a terminated bus with all transmitters disabled, the receivers differential input voltage is pulled to 0v by the termination resistor. with the receiver thresholds of the max13450e, this results in ro being logic-high. the MAX13451E has the same fail-safe receiver behavior as the max13450e when the inv input is low. when the inv input is high, ro is low under the fail-safe condition. esd protection as with all maxim devices, esd-protection structures are incorporated on all pins to protect against elec - trostatic discharges encountered during handling and assembly. the driver outputs and receiver inputs of the max13450e/MAX13451E have extra protection against static electricity. the esd structures withstand high esd in all states: normal operation, shutdown, and powered down. after an esd event, the max13450e/MAX13451E keep working without latchup or damage. esd protection can be tested in various ways. the trans - mitter outputs and receiver inputs of the max13450e/ MAX13451E are characterized for protection to the fol - lowing limits: ? q 30kv using the human body model ? q 15kv using the air gap discharge method specified in iec 61000-4-2 ? q 7kv using the contact discharge method specified in iec 61000-4-2 esd test conditions esd performance depends on a variety of conditions. contact maxim for a reliability report that documents test setup, test methodology, and test results. human body model figure 11a shows the human body model, and figure 11b 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 interest, which is then discharged into the test device through a 1.5k i resistor. iec 61000-4-2 the iec 61000-4-2 standard covers esd testing and performance of finished equipment. however, it does not specifically refer to integrated circuits. the max13450e/ MAX13451E help equipment designs to meet iec 61000- 4-2, without the need for additional esd-protection components. the major difference between tests done using the human body model and iec 61000-4-2 is higher peak current in iec 61000-4-2 because series resistance is lower in the iec 61000-4-2 model. hence, the esd withstand voltage measured to iec 61000-4-2 is generally lower than that measured using the human body model. figure 11c shows the iec 61000-4-2 model, and figure 11d shows the current waveform for the iec 61000-4-2 esd contact discharge test. applications information typical applications the max13450e transceiver is designed for full-duplex, bidirectional data communications on point-to-point or multipoint bus transmission lines (figure 12). the MAX13451E transceiver is designed for half-duplex, bidirectional data communications on point-to-point or multipoint bus transmission lines (figure 13). 256 transceivers on the bus the standard rs-485 receiver input impedance is one- unit load, and the standard driver can drive up to 32-unit loads. the max13450e/MAX13451E have a 1/8-unit load receiver input impedance, allowing up to 256 transceiv - ers to be connected in parallel on one communication line. any combination of these devices, as well as other rs-485 transceivers with a total of 32-unit loads or fewer, can be connected to the line. reduced emi and reflections the max13450e/MAX13451E feature reduced slew-rate drivers that minimize emi and reduce reflections caused by improperly terminated cables, allowing error-free data transmission up to 500kbps.
rs-485 transceivers with integrated 100 ? /120 ? termination resistors max13450e/MAX13451E ______________________________________________________________________________________ 15 figure 11a. human body esd test model figure 11b. human body current waveform figure 11c. iec 61000-4-2 esd test model figure 11d. iec 61000-4-2 esd generator current waveform figure 12. full-duplex, multidrop (max13450e) typical application circuits charge-current limit resistor discharge resistance storage capacitor c s 100pf r c 1m ? r d 1500 ? high- voltage dc source device under test 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 amps charge-current limit resistor discharge resistance storage capacitor c s 150pf r c 50m ? to 100m ? r d 330 ? high- voltage dc source device under test t r = 0.7ns to 1ns 30ns 60ns t 100% 90% 10% i peak i max13450e d z y b a b a z y r max13450e r d d slave 1 master end slave r d slave 2 r d slave n r
rs-485 transceivers with integrated 100 ? /120 ? termination resistors max13450e/MAX13451E 16 _____________________________________________________________________________________ low-power shutdown mode drive re high, de low, and term high to enter low- power shutdown mode (see table 2). chip information process: bicmos package information for the latest package outline information and land patterns, 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. figure 13. half-duplex, multidrop, and point-to-point systems (MAX13451E) typical application circuits (continued) d slave 1 r d slave 2 r d slave n r d b a r d b a r MAX13451E MAX13451E package type package code document no. 14 tssop-ep u14e+3 21-0108
rs-485 transceivers with integrated 100 ? /120 ? termination resistors max13450e/MAX13451E maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a maxim product. no circuit patent licenses are implied. maxim reserves the right to change the circuitry and specifications without notice at any time. maxim integrated products, 120 san gabriel drive, sunnyvale, ca 94086 408-737-7600 17 ? 2010 maxim integrated products maxim is a registered trademark of maxim integrated products, inc. revision history revision number revision date description pages changed 0 4/10 initial release

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