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1 fault protected, extended cmr, rs-485/rs-422 transceivers with cable invert and 16.5kv esd ISL32483E, isl32485e the isl3248xe are fault protected, 5v powered differential transceivers that exceed the rs-485 and rs-422 standards for balanced communication. the rs-485 transceiver pins (driver outputs and receiver inputs) are fault protected up to 60v and are protected against 16.5kv esd strikes without latch-up. additionally, the extended common mode range allows these transceivers to operate in environments with common mode voltages up to 25v (>2x the rs-485 requirement), making this fault-protected rs-485 family one of the most robust on the market. transmitters (tx) deliver an exceptional 2.5v (typical) differential output voltage into the rs-485 specified 54 ? load. this yields better noise immunity than standa rd rs-485 ics or allows up to six 120 ? terminations in star network topologies. receiver (rx) inputs feature a ?full fail-safe? design, which ensures a logic high rx output if rx inputs are floating, shorted, or on a terminated but undriven (idle) bus. the ISL32483E and isl32485e include cable invert functions that reverse the polarity of the rx and/or tx bus pins in case the cable is misconnected. unlike competing devices, rx full fail-safe operation is maintained even wh en the rx input polarity is switched. for fault protected rs-485 transceivers without the cable invert function, please see the isl32470e and isl32490e data sheets. features ? fault protected rs-485 bus pins . . . . . . . . . . . . . . up to 60v ? extended common mode range . . . . . . . . . . . . . . . . . . . 25v more than twice the range required for rs-485 ? 16.5kv hbm esd protection on rs-485 bus pins ?cable invert pins corrects for reversed cable connections while maintaining rx full fail-safe functionality ? full fail-safe (open, short, terminated) rs-485 receivers ? 1/4 unit load (ul) for up to 128 devices on the bus ?high rx i ol for opto-couplers in isolated designs ? hot plug circuitry: tx and rx outputs remain three-state during power-up/power-down ? slew rate limited rs-485 data rate . . . . . . . . . . . . . 1mbps ? low quiescent supply current . . . . . . . . . . . . . . . . . . . 2.3ma ? ultra low shutdown supply current . . . . . . . . . . . . . . . 10a applications ? utility meters/automated meter reading systems ? high node count rs-485 systems ?profibus ? and rs-485 based field bus networks, and factory automation ?security camera networks ? building lighting and environmental control systems ? industrial/process control networks figure 1. exceptional rx oper ates at 1mbps even with 25v common mode voltage figure 2. transceivers deliver superior common mode range vs standard rs-485 devices -5 0 5 10 15 20 25 30 time (400ns/div) voltage (v) b vid = 1v a ro isl3248xe common mode range closest competitor standard rs-485 transceiver -25 -20 -12 -7 0 12 25 january 18, 2011 fn7785.0 caution: these devices are sensitive to electrostatic discharge; follow proper ic handling procedures. 1-888-intersil or 1-888-468-3774 | copyright intersil americas inc. 2011. all rights reserved intersil (and design) is a trademark owned by intersil corporation or one of its subsidiaries. all other trademarks mentioned are the property of their respective owners.
ISL32483E, isl32485e 2 fn7785.0 january 18, 2011 table 1. summary of features part number half/full duplex data rate (mbps) slew-rate limited? en pins? hot plug polarity reversal pins? quiescent i cc (ma) low power shdn? pin count ISL32483E full 1 yes yes yes yes 2.3 yes 14 isl32485e half 1 yes tx only yes yes 2.3 no 8 ordering information part number (notes 1, 2, 3) part marking temp. range (c) package (pb-free) pkg. dwg. # ISL32483Eibz isl32483 eibz -40 to +85 14 ld soic m14.15 isl32485eibz 32485 eibz -40 to +85 8 ld soic m8.15 notes: 1. add ?-t*? suffix for tape and reel. please refer to tb347 for details on reel specifications. 2. these intersil pb-free plastic packaged products employ spec ial pb-free material sets, molding compounds/die attach materials , and 100% matte tin plate plus anneal (e3 termination finish , which is rohs compliant and compatible wi th both snpb and pb-free soldering opera tions). intersil pb-free products are msl classified at pb-fr ee peak reflow temperatures that meet or exceed the pb-free requirements of ipc/jed ec j std-020. 3. for moisture sensitivity level (msl), please see device information page for ISL32483E and isl32485e . for more information on msl please see techbrief tb363 . pin configurations ISL32483E (14 ld soic) top view isl32485e (8 ld soic) top view rinv ro re de di gnd gnd vcc vcc a b z y dinv 1 2 3 4 5 6 7 14 13 12 11 10 9 8 d r ro inv de di 1 2 3 4 8 7 6 5 vcc b/z a/y gnd d r
ISL32483E, isl32485e 3 fn7785.0 january 18, 2011 pin descriptions pin name ISL32483E pin # isl32485e pin # function ro 2 1 receiver output. if inv or rinv is low, then: if a - b -10mv, ro is high; if a - b -200mv, ro is low. if inv or rinv is high, then: if b - a -10mv, ro is high; if b - a -200mv, ro is low. in all cases, ro = high if a and b are unconnected (floating), or shorted together, or connected to an undriven, terminated bus (i.e., rx is always failsafe open, shorted, and idle, even if polarity is inverted). re 3 n/a receiver output enable. ro is enabled when re is low; ro is high impedance when re is high. internally pulled low. de 4 3 driver output enable. the driver outputs, y and z, are enabled by bringing de high, and they are high impedance when de is low. internally pulled high to v cc . di 5 4 driver input. if inv or dinv is low, a low on di forces output y low and output z high, while a high on di forces output y high and output z low. the output states relative to di invert if inv or dinv is high. gnd 6, 7 5 ground connection. a/y n/a 6 60v fault and 16.5kv hbm esd protected rs-485/rs-422 level i/o pin. if inv is low, a/y is the non-inverting receiver input and non-inverting driver outp ut. if inv is high, a/y is the inverting receiver input and the inverting driver output. pin is an in put if de = 0; pin is an output if de = 1. b/z n/a 7 60v fault and 16.5kv hbm esd protected rs-485/rs-422 level i/o pin. if inv is low, b/z is the inverting receiver input and inverting driver output. if inv is high, b/z is the non-inverting receiver input and the non-inverting driver output. pin is an input if de = 0; pin is an output if de = 1. a 12 n/a 60v fault and 15kv hbm esd protected rs-485/rs-422 level input. if rinv is low, then a is the non-inverting receiver input. if rinv is hi gh, then a is the inverting receiver input. b 11 n/a 60v fault and 15kv hbm esd protected rs-485/rs-422 level input. if rinv is low, then b is the inverting receiver input. if rinv is high, then b is the non-inverting receiver input. y 9 n/a 60v fault and 15kv hbm esd protected rs-485/rs-422 level output. if dinv is low, then y is the non-inverting driver output. if dinv is high, then y is the inverting driver output z 10 n/a 60v fault and 15kv hbm esd protected rs-485/rs-422 level. if dinv is low, then z is the inverting driver output. if dinv is high, then z is the non-inverting driver output vcc 13, 14 8 system power supply input (4.5v to 5.5v). inv n/a 2 receiver and driver polarity select ion input. when driven high, this pin sw aps the polarity of the driver output and receiver input pins. if unconnected (floating) or connected low, normal rs-485 polarity conventions apply. internally pulled low. rinv 1 n/a receiver polarity selection input. when driven high, this pin swaps the polarity of the receiver input pins. if unconnected (floating) or connected low, normal rs- 485 polarity conventions appl y. internally pulled low. dinv 8 n/a driver polarity selection input. when driven high, this pin swaps the po larity of the driver output pins. if unconnected (floating) or connected low, normal rs- 485 polarity conventions appl y. internally pulled low.
ISL32483E, isl32485e 4 fn7785.0 january 18, 2011 truth tables transmitting inputs outputs re de di inv or dinv y z x11 0 1 0 x10 0 0 1 x11 1 0 1 x10 1 1 0 0 0 x x high-z high-z 10x xhigh-z (see note) high-z (see note) note: low power shutdown mode (see note 11 on page 7), except for isl32485e. receiving inputs output re de (half duplex) de (full duplex) a-b inv or rinv ro 00 x -0.01v 0 1 00 x -0.2v 0 0 00 x 0.01v 1 1 00 x 0.2v 1 0 00 x inputs open or shorted x1 10 0 x xhigh-z (see note) 11 1 x xhigh-z note: low power shutdown mode (see note 11 on page 7), except for isl32485e. typical operating circuits isl34183e full duplex example 0.1f + d r 11 12 9 10 13, 14 2 3 4 5 6, 7 v cc gnd ro re de di b a z y +5v 0.1f + d r 12 11 10 9 13, 14 2 3 4 5 6, 7 v cc gnd ro re de di a b y z +5v r t r t dinv 1 the ic on the left has the cable connections swapped, so the inv pins (1, 8) are strapped high to invert its rx and tx polarity 8 rinv rinv dinv 1 8
ISL32483E, isl32485e 5 fn7785.0 january 18, 2011 absolute maximum rating s thermal information v cc to ground . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7v input voltages di, inv, rinv, dinv, de, re . . . . . . . . . . . . . . . . . . . . -0.3v to (v cc + 0.3v) input/output voltages a/y, b/z, a, b, y, z. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60v a/y, b/z, a, b, y, z (transient pulse through 100 ? , see note 15). . . . . . . . . . . . . . . . . 80v ro . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3v to (v cc +0.3v) short circuit duration y, z. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . indefinite esd rating . . . . . . . . . . . . . . . . . . . . see ?esd performance? on page 6 latch-up (tested per jesd78, level 2, class a). . . . . . . . . . . . . . . . +125c thermal resistance (typical) ja (c/w) jc (c/w) 8 ld soic package (notes 4, 5). . . . . . . . . . 116 47 14 ld soic package (notes 4, 5) . . . . . . . . 88 39 maximum junction temperature (plastic package) . . . . . . . . . . . . +150c maximum storage temperature range . . . . . . . . . . . . . . -65c to +150c pb-free reflow profile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . see link below http://www.intersil.com/pbfree/pb-freereflow.asp recommended operating conditions supply voltage (v cc ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5v temperature range. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -40c to +85c bus pin common mode voltage range . . . . . . . . . . . . . . . . . -25v to +25v caution: do not operate at or near the maximum ratings listed fo r extended periods of time. exposure to such conditions may adv ersely impact product reliability and result in failures not covered by warranty. notes: 4. ja is measured with the component mounted on a high effective thermal conductivity test board in free air. see tech brief tb379 for details. 5. for jc , the ?case temp? location is taken at the package top center. electrical specifications test conditions: v cc = 4.5v to 5.5v; unless otherwise specified. typicals are at v cc = 5v, t a = +25c (note 6). boldface limits apply over the operating temperature range, -40c to +85c. parameter symbol test conditions temp (c) min (note 14) typ max (note 14) units dc characteristics driver differential v out (no load) v od1 full - - v cc v driver differential v out (loaded, figure 3a) v od2 r l = 100 ? (rs-422) full 2.4 3.2 - v r l = 54 ? (rs-485) full 1.5 2.5 v cc v r l = 54 ? (profibus, v cc 5v) full 2.0 2.5 - v r l = 21 ? (six 120 ? terminations for star configurations, v cc 4.75v) full 0.8 1.3 - v change in magnitude of driver differential v out for complementary output states v od r l = 54 ? or 100 ? (figure 3a) full - - 0.2 v driver differential v out with common mode load (figure 3b) v od3 r l = 60 ? , -7v v cm 12v full 1.5 2.1 v cc v r l = 60 ? , -25v v cm 25v (v cc 4.75v) full 1.7 2.3 v r l = 21 ? , -15v v cm 15v (v cc 4.75v) full 0.8 1.1 - v driver common-mode v out (figure 3) v oc r l = 54 ? or 100 ? full -1 - 3 v r l = 60 ? or 100 ? , -20v v cm 20v full -2.5 - 5 v change in magnitude of driver common-mode v out for complementary output states dv oc r l = 54 ? or 100 ? (figure 3a) full - - 0.2 v driver short-circuit current i osd de = v cc , -25v v o 25v (note 8) full -250 - 250 ma i osd1 at first fold-back, 22v v o -22v full -83 83 ma i osd2 at second fold-back, 35v v o -35v full -13 13 ma logic input high voltage v ih de, di, re , inv, rinv, dinv full 2.5 - - v logic input low voltage v il de, di, re , inv, rinv, dinv full - - 0.8 v logic input current i in1 di full -1 - 1 a de, re , inv, rinv, dinv full -15 6 15 a
ISL32483E, isl32485e 6 fn7785.0 january 18, 2011 input/output current (a/y, b/z) i in2 de = 0v, v cc = 0v or 5.5v v in = 12v full - 110 250 a v in = -7v full -200 -75 - a v in = 25v full -800 240 800 a v in = 60v (note 17) full -6 0.7 6 ma input current (a, b) (full duplex versions only) i in3 v cc = 0v or 5.5v v in = 12v full - 90 125 a v in = -7v full -100 -70 - a v in = 25v full -500 200 500 a v in = 60v (note 17) full -3 0.5 3 ma output leakage current (y, z) (full duplex versions only) i ozd re = 0v, de = 0v, v cc = 0v or 5.5v v in = 12v full - 20 200 a v in = -7v full -100 -5 - a v in = 25v full -500 40 500 a v in = 60v (note 17) full -3 0.15 3 ma receiver differential threshold voltage v th a-b if inv or rinv = 0; b-a if inv or rinv = 1, -25v v cm 25v full -200 -100 -10 mv receiver input hysteresis dv th -25v v cm 25v 25 - 25 - mv receiver output high voltage v oh v id = -10mv i o = -2ma full v cc - 0.5 4.75 - v i o = -8ma full 2.8 4.2 - v receiver output low voltage v ol i o = 6ma, v id = -200mv full - 0.27 0.4 v receiver output low current i ol v o = 1v, v id = -200mv full 15 22 - ma three-state (high impedance) receiver output current i ozr 0v v o v cc (note 16) full -1 0.01 1 a receiver short-circuit current i osr 0v v o v cc full 12 - 110 ma supply current no-load supply current (note 7) i cc de = v cc , re =0v or v cc , di = 0v or v cc full - 2.3 4.5 ma shutdown supply current i shdn de = 0v, re = v cc , di = 0v or v cc (note 16) full - 10 50 a esd performance rs-485 pins (a, y, b, z, a/y, b/z) human body model, from bus pins to gnd 1/2 duplex 25 - 16.5 - kv full duplex 25 - 15 - kv all pins human body model, per jedec 25 - 8 - kv machine model 25 - 700 - v driver switching characteristics driver differential output delay t plh, t phl r d = 54 ? , c d =50pf (figure 4) no cm load full - 70 125 ns -25v v cm 25v full - - 350 ns driver differential output skew t skew r d = 54 ? , c d =50pf (figure 4) no cm load full - 4.5 15 ns -25v v cm 25v full - - 25 ns driver differential rise or fall time t r , t f r d = 54 ? , c d =50pf (figure 4) no cm load full 70 170 300 ns -25v v cm 25v full 70 - 400 ns maximum data rate f max c d = 820pf (figure 6) full 1 4 - mbps driver enable to output high t zh sw = gnd (figure 5), (note 9) full - - 350 ns driver enable to output low t zl sw = v cc (figure 5), (note 9) full - - 300 ns driver disable from output low t lz sw = v cc (figure 5) full - - 120 ns electrical specifications test conditions: v cc = 4.5v to 5.5v; unless otherwise specified. typicals are at v cc = 5v, t a = +25c (note 6). boldface limits apply over the operating temperature range, -40c to +85c. (continued) parameter symbol test conditions temp (c) min (note 14) typ max (note 14) units
ISL32483E, isl32485e 7 fn7785.0 january 18, 2011 driver disable from output high t hz sw = gnd (figure 5) full - - 120 ns time to shutdown t shdn (notes 11, 16) full 60 160 600 ns driver enable from shutdown to output high t zh(shdn) sw = gnd (figure 5), (notes 11, 12, 16) full - - 2000 ns driver enable from shutdown to output low t zl(shdn) sw = v cc (figure 5), (notes 11, 12, 16) full - - 2000 ns receiver switching characteristics maximum data rate f max -25v v cm 25v (figure 7) full 1 15 - mbps receiver input to output delay t plh , t phl -25v v cm 25v (figure 7) full - 90 150 ns receiver skew | t plh - t phl |t skd (figure 7) full - 4 10 ns receiver enable to output low t zl r l = 1k ? , c l = 15pf, sw = v cc (figure 8), (notes 10, 16) full - - 50 ns receiver enable to output high t zh r l = 1k ? , c l = 15pf, sw = gnd (figure 8), (notes 10, 16) full - - 50 ns receiver disable from output low t lz r l = 1k ? , c l = 15pf, sw = v cc (figure 8) (note 16) full - - 50 ns receiver disable from output high t hz r l = 1k ? , c l = 15pf, sw = gnd (figure 8) (note 16) full - - 50 ns time to shutdown t shdn (notes 11, 16) full 60 160 600 ns receiver enable from shutdown to output high t zh(shdn) r l = 1k ? , c l = 15pf, sw = gnd (figure 8), (notes 11, 13, 16) full - - 2000 ns receiver enable from shutdown to output low t zl(shdn) r l = 1k ? , c l = 15pf, sw = v cc (figure 8), (notes 11, 13, 16) full - - 2000 ns notes: 6. all currents into device pins are positive; all currents out of device pins are negative. all voltages are referenced to devi ce ground unless otherwise specified. 7. supply current specification is valid for loaded drivers when de = 0v. 8. applies to peak current. see ?typical performance curves? beginning on page 18 for more information 9. keep re = 0 to prevent the device from entering shdn. 10. the re signal high time must be short enough (typically <100ns) to prevent the device from entering shdn. 11. transceivers (except on the isl32485e) are put into shutdown by bringing re high and de low. if the inputs are in this state for less than 60ns, the parts are guaranteed not to enter shutdown. if the inputs are in this state for at least 600ns, the parts are guaranteed to hav e entered shutdown. see ?low power shutdown mode? on page 12. 12. keep re = vcc, and set the de signal low time >600ns to ensure that the device enters shdn. 13. set the re signal high time >600ns to ensu re that the device enters shdn. 14. compliance to data sheet limits is assu red by one or more methods: production test, characterization and/or design. 15. tested according to tia/ei a-485-a, section 4.2.6 (80v for 15ms at a 1% duty cycle). 16. does not apply to the isl32485e. the isl32485e has no rx enable function, and thus no shdn function. 17. see ?caution? statement in the ?recommend ed operating conditions? section on page 5. electrical specifications test conditions: v cc = 4.5v to 5.5v; unless otherwise specified. typicals are at v cc = 5v, t a = +25c (note 6). boldface limits apply over the operating temperature range, -40c to +85c. (continued) parameter symbol test conditions temp (c) min (note 14) typ max (note 14) units
ISL32483E, isl32485e 8 fn7785.0 january 18, 2011 test circuits and waveforms figure 3a. v od and v oc figure 3b. v od and v oc with common mode load figure 3. dc driver test circuits figure 4a. test circuit figure 4b. measurement points figure 4. driver propagation delay and differential transition times figure 5a. test circuit figure 5b. measurement points figure 5. driver enable and disable times d de di v cc v od v oc r l /2 r l /2 z y d de di v cc v od 375 ? 375 ? z y v cm r l /2 r l /2 v oc d de di v cc signal generator r d z y 375 ? * 375 ? * c d v cm *only used for common mode load tests out (z) 0v 50% 50% v oh v ol out (y) t plh t phl diff out (y - z) t r +v od -v od 90% 90% t f 10% 10% di skew = |t plh - t phl | 3v d de di z y v cc gnd sw parameter output re di sw c l (pf) t hz y/z x 1/0 gnd 50 t lz y/z x 0/1 v cc 50 t zh y/z 0 (note 9) 1/0 gnd 100 t zl y/z 0 (note 9) 0/1 v cc 100 t zh(shdn) y/z 1 (note 12) 1/0 gnd 100 t zl(shdn) y/z 1 (note 12) 0/1 v cc 100 signal generator 110 ? c l out (y, z) 0v 50% 50% v oh 0v v oh - 0.5v t hz out (y, z) v cc v ol v ol + 0.5v t lz de output low t zl , t zl(shdn) t zh , t zh(shdn) 2.3v 2.3v 3v (note 11) (note 11) (note 11) output high
ISL32483E, isl32485e 9 fn7785.0 january 18, 2011 figure 6a. test circuit figure 6b. measurement points figure 6. driver data rate figure 7a. test circuit figure 7b. measurement points figure 7. receiver propagation delay and data rate figure 8a. test circuit figure 8b. measurement points figure 8. receiver enable and disable times test circuits and waveforms (continued) d de di v cc signal generator z y c d v od + - 54 ? 0v diff out (y - z) +v od -v od di 0v 3v signal generator r ro re a b 15pf signal generator v cm ro v cm + 750mv v cm - 750mv t plh v cm v cm v cc 0v 50% 50% t phl a b 1k ? gnd sw parameter de a sw t hz 0 +1.5v gnd t lz 0 -1.5v v cc t zh (note 10) 0 +1.5v gnd t zl (note 10) 0 -1.5v v cc t zh(shdn) (note 13) 0 +1.5v gnd t zl(shdn) (note 13) 0 -1.5v v cc signal generator r ro re a b 15pf v cc ro 0v 50% 50% v oh 0v 1.5v v oh - 0.5v t hz ro v ol 1.5v v ol + 0.5v t lz re output low t zl , t zl(shdn) t zh , t zh(shdn) 3v v cc (note 11) (note 11) (note 11) output high
ISL32483E, isl32485e 10 fn7785.0 january 18, 2011 application information rs-485 and rs-422 are differential (balanced) data transmission standards used for lo ng haul or noisy environments. rs-422 is a subset of rs-485, so rs-485 transceivers are also rs-422 compliant. rs-422 is a point-to-multipoint (multidrop) standard, which allows only one driver and up to 10 (assuming one-unit load devices) receivers on each bus. rs-485 is a true multipoint standard, which allows up to 32 one-unit load devices (any combination of drivers and receivers) on each bus. to allow for multipoint operation, the rs-4 85 specification requires that drivers must handle bus contention without sustaining any damage. another important advantage of rs-485 is the extended common mode range (cmr), whic h specifies that the driver outputs and receiver inputs with stand signals that range from +12v to -7v. rs-422 and rs-485 ar e intended for runs as long as 4000 feet, so the wide cmr is necessary to handle ground potential differences, as well as voltages induced in the cable by external fields. the isl3248xe is a family of ruggedized rs-485 transceivers that improves on the rs-485 ba sic requirements and therefore increases system reliability. th e cmr increases to 25v, while the rs-485 bus pins (receiver inputs and driver outputs) include fault protection against voltages and transients up to 60v. additionally, larger-than-required differential output voltages (v od ) increase noise immunity, wh ile the 16.5kv built-in esd protection complements the fault protection. receiver (rx) features these devices utilize a differential input receiver for maximum noise immunity and common mode re jection. input sensitivity is better than 200mv, as required by the rs-422 and rs-485 specifications. receiver input (load) current su rpasses the rs-422 specification of 3ma and is four times lower than the rs-485 ?unit load (ul)? requirement of 1ma maximum. thus, these products are known as ?one-quarter ul? transceivers, and there can be up to 128 of these devices on a network while still complying with the rs-485 loading specification. the rx functions with common mo de voltages as great as 25v, making them ideal for industrial or long networks where induced voltages are a realistic concern. all the receivers include a ?full fail -safe? function that guarantees a high-level receiver output if the receiver inputs are unconnected (floating), shorted together, or connected to a terminated bus with all the transmitters di sabled (i.e., an idle bus). rx outputs feature high drive levels (typically 22ma @ v ol =1v) to ease the design of optically coupled isolated interfaces. except for the isl32485e, rx outputs are thr ee-statable via the active low re input. the rx includes noise filtering circuitry to reject high-frequency signals, and typically reject s pulses narrower than 50ns (equivalent to 20mbps). driver (tx) features the rs-485/rs-422 driver is a diff erential output device that delivers at least 1.5v across a 54 ? load (rs-485) and at least 2.4v across a 100 ? load (rs-422). the drivers feature low propagation delay skew to maximize bit width and to minimize emi, and all drivers are three-st atable via the active high de input. the driver outputs are slew rate limited to minimize emi and to minimize reflections in unterminated or improperly terminated networks. high overvoltage (fault) protection increases ruggedness the 60v (referenced to the ic gnd) fault protection on the rs-485 pins makes these transcei vers some of the most rugged on the market. this level of protection makes the isl3248xe perfect for applications where power (e.g., 24v and 48v supplies) must be routed in the conduit with the data lines, or for outdoor applications where large transients are likely to occur. when power is routed with the data lines, even a momentary short between the supply and data lines will destroy an unprotected device. the 60v fault levels of this family are at least five times higher than the levels specified for standard rs-485 ics. the isl3248xe protection is active whether the tx is enabled or disabled, and even if the ic is powered down. if transients or voltages (inc luding overshoots and ringing) greater then 60v are possible, then additional external protection is required. widest common mode voltage (cmv) tolerance improves operating range rs-485 networks operating in industrial complexes or over long distances are susceptible to large cmv variations. either of these operating environments may suffer from large node-to-node ground potential differences or cmv pickup from external electromagnetic sources, and devices with only the minimum required +12v to -7v cmr may malfunction. the isl3248xe?s extended 25v cmr is the widest av ailable, allowing operation in environments that would overwhelm lesser transceivers. additionally, the rx will not phase invert (erroneously change state), even with cmvs of 40v or differential voltages as large as 40v. cable invert (polarity reversal) function with large node count rs-485 networks, it is common for some cable data lines to be wired backwards during installation. when this happens, the node is un able to communicate over the network. once a technician finds the miswired node, he must then rewire the connector, which is time consuming. the ISL32483E and isl32485e simp lify this task by including cable invert pins (inv, dinv, rinv) that allow the technician to invert the polarity of the rx input and/or the tx output pins simply by moving a jumper to change the state of the invert pins. when the invert pin is low, the ic operates like any standard rs-485 transceiver, and the bus pi ns have their normal polarity definition of a and y being noninverting and b and z being inverting. with the invert pin high, the corresponding bus pins reverse their polarity, so b and z are now noninverting, and a and y become inverting.
ISL32483E, isl32485e 11 fn7785.0 january 18, 2011 intersil?s unique cable invert function is superior to that found on competing devices, because the rx full fail-safe function is maintained, even when the rx polarity is reversed. competitor devices implement the rx invert function simply by inverting the rx output. this means that with the rx inputs floating or shorted together, the rx appropriately delivers a logic 1 in normal polarity, but outputs a logic low when the ic is operated in the inverted mode. intersil?s innovative rx design guarantees that, with the rx inputs floating or shorted together (v id =0v), the rx output remains high, regardless of the state of the invert pins. the full duplex ISL32483E includes two invert pins that allow for separate control of the rx and tx po larities. if only the rx cable is miswired, then only the rinv pin need be driven to a logic 1. if the tx cable is miswired, then dinv must be connected to a logic high. the half-duplex version has only one logic pin (inv) that, when high, switches the polarity of both the tx and the rx blocks. high v od improves noise immunity and flexibility the isl3248xe driver design delivers larger differential output voltages (v od ) than the rs-485 standard requires or than most rs-485 transmitters can deliver. the typical 2.5v v od provides more noise immunity than networks built using many other transceivers. another advantage of the large v od is the ability to drive more than two bus terminations, which allows for utilizing the isl3248xe in ?star? and other multi-terminated, nonstandard network topologies. figure 10 details the transmitter?s v od versus i out characteristic, and includes load lines for four (30 ? ) and six (20 ? ) 120 ? terminations. the figure shows that the driver typically delivers 1.3v into six terminations, and the ?electrical specifications? on page 5 guarantee a v od of 0.8v at 21 ? over the full temperature range. the rs-485 standard requires a minimum 1.5v v od into two terminations, but the isl3248xe delivers rs-485 voltage levels with 2x to 3x the number of terminations. hot plug function when a piece of equipment powers up, there is a period of time in which the processor or asic driving the rs-485 control lines (de, re ) is unable to ensure that the rs-485 tx and rx outputs are kept disabled. if the equipment is connected to a bus, a driver activating prematurely during power-up may crash the bus. to avoid this scenario, the isl3248xe devices incorporate a ?hot plug? function. circuitry monitoring v cc ensures that, during power-up and power-down, the tx and rx outputs remain disabled, regardless of the state of de and re , if v cc is less than 3.5v. this gives the processor or asic a ch ance to stabilize and drive the rs-485 control lines to the proper states. figure 9 illustrates the power-up and power-down performance of the isl3248xe compared to an rs-485 ic without the hot plug feature. esd protection all pins on the isl3248xe devices include class 3 (>8kv) human body model (hbm) esd prot ection structures that are good enough to survive esd ev ents commonly seen during manufacturing. even so, the rs-485 pins (driver outputs and receiver inputs) incorporate mo re advanced structures that allow them to survive esd events in excess of 16.5kv hbm (15kv for full-duplex version). the rs-485 pins are particularly vulnerable to esd strikes, becaus e they typically connect to an exposed port on the exterior of the finished product. simply touching the port pins or conn ecting a cable can cause an esd event that might destroy un protected ics. the new esd structures protect the device wh ether or not it is powered up, and without interfering with th e exceptional 25v cmr. this built-in esd protection minimizes the need for board-level protection structures (e.g., tr ansient suppression diodes) and the associated, undesirable ca pacitive load they present. data rate, cables, and terminations rs-485/rs-422 are intended for network lengths up to 4000 feet, but the maximum system data rate decreases as the transmission length increases. these 1mbps versions can operate at full data rates with lengths up to 800 feet (244m). jitter is the limiting parameter at this data rate, so employing encoded data streams (e.g., manchester coded or return-to-zero) may allow increased transmission distances. twisted pair is the cable of choice for rs-485/rs-422 networks. twisted pair cables tend to pick up noise and other electromagnetically induced voltag es as common mode signals, which are effectively rejected by the differential receivers in these ics. figure 9. hot plug performance ( isl3248xe ) vs isl83088e without hot plug circuitry time (40s/div) v cc receiver output (v) driver y output (v) 2.5 5.0 2.5 5.0 vcc (v) rl = 1k ? ro 0 2.5 5.0 0 0 a/y rl = 1k ? 3.5v re = gnd de, di = v cc 2.8v isl3248xe isl3248xe isl83088e
ISL32483E, isl32485e 12 fn7785.0 january 18, 2011 proper termination is imperative to minimize reflections, and terminations are recommended unless power dissipation is an overriding concern. in point-to-poi nt, or point-to-multipoint (single driver on bus like rs-422) networks, the main cable should be terminated in its characteristic impedance (typically 120 ? ) at the end farthest from the driver. in multi-receiver applications, stubs connecting receivers to the main ca ble should be kept as short as possible. multipoint (m ulti-driver) systems require that the main cable be terminated in its charac teristic impedance at both ends. stubs connecting a transceiver to the main cable should be kept as short as possible. built-in driver overload protection as stated previously, the rs-485 specification requires that drivers survive worst-case bus contentions undamaged. these transceivers meet this requiremen t via driver output short circuit current limits and on-chip thermal shutdown circuitry. the driver output stages incorporate a double foldback, short circuit current limiting scheme, which ensures that the output current never exceeds the rs-485 specification, even at the common mode and fault condition voltage range extremes. the first foldback current level ( 70ma) is set to ensure that the driver never folds back when driving loads with common mode voltages up to 25v. the very low second foldback current setting ( 9ma) minimizes power dissipation if the tx is enabled when a fault occurs. in the event of a major short circui t condition, devices also include a thermal shutdown feature that di sables the drivers whenever the die temperature becomes excessive. this eliminates the power dissipation, allowing the die to cool. the drivers automatically re-enable after the die temperature drops about 15c. if the contention persists, the thermal shutdown/re-enable cycle repeats until the fault is cleared. receiver s stay operational during thermal shutdown. low power shutdown mode these bicmos transceivers all use a fraction of the power required by competitive devices, but they also include a shutdown feature (except the isl32485e) that reduces the already low quiescent i cc to a 10a trickle. these devices enter shutdown whenever the receiver and driver are simultaneously disabled (re =v cc and de = gnd) for a period of at least 600ns. disabling both the driver and the receiver for less than 60ns guarantees that the transcei ver will not enter shutdown. note that receiver and driver enable times increase when the transceiver enables from shutdown. refer to notes 9, 10, 11, 12 and 13, at the end of ?electrica l specifications? on page 5, for more information. typical performance curves v cc = 5v, t a = +25 c; unless otherwise specified. figure 10. driver output current vs differential output voltage figure 11. driver differential output voltage vs temperature differential output voltage (v) driver output current (ma) 012345 0 10 20 30 40 50 60 70 80 90 +25c r d = 54 ? r d = 100 ? r d = 30 ? r d = 20 ? +85c -40 0 50 85 temperature (c) differential output voltage (v) -25 25 75 r d = 54 ? r d = 100 ? 2.2 2.4 2.6 2.8 3.0 3.2 3.4 3.6
ISL32483E, isl32485e 13 fn7785.0 january 18, 2011 figure 12. supply current vs temperature figure 13 . receiver output curren t vs receiver output voltage figure 14. driver output current vs short circuit voltage figure 15. bus pin current vs bus pin voltage figure 16. driver differential propagation delay vs temperature figure 17. driver differenti al skew vs temperature typical performance curves v cc = 5v, t a = +25 c; unless otherwise specified. (continued) -40 0 50 85 temperature (c) icc (ma) -25 25 75 2.00 2.05 2.10 2.15 2.20 2.25 2.30 2.35 2.40 2.45 de = v cc , re = x de = gnd, re = gnd receiver output voltage (v) receiver output current (ma) -30 -20 -10 0 10 20 30 40 50 60 70 v oh , +25c v oh , +85c v ol , +25c v ol , +85c 012345 output voltage (v) output current (ma) -150 -100 -50 0 50 100 150 -60-50-40-30-20-10 0 102030405060 y or z = high y or z = low +85c +85c +25c +25c bus pin voltage (v) bus pin current (a) -600 -400 -200 0 200 400 600 800 -70 -50 -30 -10 0 10 30 50 70 a/y or b/z y or z -40 0 50 85 temperature (c) -25 25 75 propagation delay (ns) 50 55 60 65 70 75 80 85 t plh t phl r d = 54 ? , c d = 50pf -40 0 50 85 temperature (c) skew (ns) -25 25 75 2.0 2.5 3.0 3.5 4.0 |t plh - t phl | r d = 54 ? , c d = 50pf
ISL32483E, isl32485e 14 fn7785.0 january 18, 2011 figure 18. receiver performance with 25v cmv figure 19. driver and receiver waveforms die characteristics substrate potential (powered up): gnd process: si gate bicmos typical performance curves v cc = 5v, t a = +25 c; unless otherwise specified. (continued) time (400ns/div) voltage (v) -25 -20 -15 -10 -5 0 5 ro a b 0 5 10 15 20 25 ro a b vid = 1v time (400ns/div) receiver output (v) r d = 54 ? , c d = 50pf 0 5 driver output (v) 0 5 driver input (v) di ro a/y - b/z -3 -2 -1 0 1 2 3
ISL32483E, isl32485e 15 intersil products are manufactured, assembled and tested utilizing iso9000 quality systems as noted in the quality certifications found at www.intersil.com/design/quality intersil products are sold by description only. intersil corporat ion reserves the right to make changes in circuit design, soft ware and/or specifications at any time without notice. accordingly, the reader is cautioned to verify that data sheets are current before placing orders. information furnished by intersil is believed to be accurate and reliable. however, no responsi bility is assumed by intersil or its subsid iaries for its use; nor for any infringem ents 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 i ntersil or its subsidiaries. for information regarding intersil corporation and its products, see www.intersil.com fn7785.0 january 18, 2011 for additional products, see www.intersil.com/product_tree products intersil corporation is a leader in the design and manufacture of high-performance analog semico nductors. the company's product s address some of the industry's fastest growing markets, such as , flat panel displays, cell phones, handheld products, and noteb ooks. intersil's product families address power management and analog sign al processing functions. go to www.intersil.com/products for a complete list of intersil product families. *for a complete listing of applications, related documentation an d related parts, please see the respective device information page on intersil.com: ISL32483E, isl32485e to report errors or suggestions for this data sheet, please go to www.intersil.com/ask our staff fits are available from our web site at http://rel.intersil.co m/reports/search.php revision history the revision history provided is for inform ational purposes only and is believed to be accurate, but not warranted. please go t o web to make sure you have the latest rev. date revision change january 18, 2011 fn7785.0 initial release
ISL32483E, isl32485e 16 fn7785.0 january 18, 2011 package outline drawing m14.15 14 lead narrow body small outline plastic package rev 1, 10/09 a d 4 0.25 a-b mc c 0.10 c 5 b d 3 0.10 a-b c 4 0.20 c 2x 2x 0.10 d c 2x h 0.10 c 6 3 6 id mark pin no.1 (0.35) x 45 seating plane gauge plane 0.25 (5.40) (1.50) 1.27 0.31-0.51 4 4 detail"a" 0.220.03 0.10-0.25 1.25 min 1.75 max (1.27) (0.6) 6.0 8.65 3.9 7 14 8 dimensioning and tolerancing conform to amsey14.5m-1994. dimension does not include interlead flash or protrusions. dimensions in ( ) for reference only. interlead flash or protrusions shall not exceed 0.25mm per side. datums a and b to be determined at datum h. 4. 5. 3. 2. dimensions are in millimeters. notes: 1. the pin #1 indentifier may be either a mold or mark feature. 6. does not include dambar protrusion. allowable dambar protrusion 7. reference to jedec ms-012-ab. shall be 0.10mm total in excess of lead width at maximum condition. detail "a" side view typical recommended land pattern top view
ISL32483E, isl32485e 17 fn7785.0 january 18, 2011 package outline drawing m8.15 8 lead narrow body small outline plastic package rev 2, 11/10 detail "a" top view index area 123 -c- seating plane x 45 notes: 1. dimensioning and tolerancing per ansi y14.5m-1982. 2. package length does not include mold flash, protrusions or gate burrs. mold flash, protrusion and gate burrs shall not exceed 0.15mm (0.006 inch) per side. 3. package width does not include interlead flash or protrusions. interlead flash and protrusions shall not exceed 0.25mm (0.010 inch) per side. 4. the chamfer on the body is optional. if it is not present, a visual index fea- ture must be located with in the crosshatched area. 5. terminal numbers are shown for reference only. 6. the lead width as measured 0.36mm (0.014 inch) or greater above the seat- ing plane, shall not exceed a maximum value of 0.61mm (0.024 inch). 7. controlling dimension: millimeter. co nverted inch dimensions are not necessarily exact. 8. this outline conforms to jedec publication ms-012-aa issue c. side view ?a side view ?b? 1.27 (0.050) 6.20 (0.244) 5.80 (0.228) 4.00 (0.157) 3.80 (0.150) 0.50 (0.20) 0.25 (0.01) 5.00 (0.197) 4.80 (0.189) 1.75 (0.069) 1.35 (0.053) 0.25(0.010) 0.10(0.004) 0.51(0.020) 0.33(0.013) 8 0 0.25 (0.010) 0.19 (0.008) 1.27 (0.050) 0.40 (0.016) 1.27 (0.050) 0.200 1 2 3 4 5 6 7 8 typical recommended land pattern 2.41 (0.095) 0.76 (0.030)

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