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1 ? fn6202.1 isl81334, isl41334 15kv esd protected, two port, dual protocol transceivers the islx1334 are two port inte rface ics where each port can be independently configured as a single rs-485/422 transceiver, or as a dual (2 tx, 2 rx) rs-232 transceiver. with both ports set to the same mode, two rs-485/422 transceivers, or four rs-232 transceivers are available. if either port is in rs- 232 mode, the onboard charge pump generates rs-232 compliant 5v tx output levels from a single v cc supply as low as 4.5v. four small 0.1 f capacitors are required for the charge pump. the transceivers are rs-232 compliant, with the rx inputs handling up to 25v, and the tx outputs handling 12v. in rs-485 mode, the transceive rs support both the rs-485 and rs-422 differential communication standards. the receivers feature "full failsafe " operation, so the rx outputs remain in a high state if the inputs are open or shorted together. the transmitters support up to three data rates, two of which are slew rate limited for problem free communications. the charge pump disables when both ports are in rs-485 mode, thereby saving power, minimizing noise, and eliminating the charge pump capacitors. both rs-232 and rs-485 modes feature loopback and shutdown functions. loopback internally connects the tx outputs to the corresponding rx input, to facilitate board level self test implementation. the outputs remain connected to the loads during loopback, so connection problems (e.g., shorted connectors or cabl es) can be detected. shutdown mode disables the tx and rx ou tputs, disables the charge pumps, and places the ic in a low current ( a) mode. the isl41334 is a qfn packaged device that includes two additional user selectable, lower speed and edge rate options for emi sensitive desi gns, or to allow longer bus lengths. it also features a logic supply pin (v l ) that sets the v oh level of logic outputs, and the switching points of logic inputs, to be compatible with another supply voltage in mixed voltage systems. the qfn also adds active low rx enable pins to increase design flexibility, allowing tx/rx direction control, via a single signal per port, by connecting the corresponding de and re pins together. for a single port version of these devices, please see the isl81387/ isl41387 data sheet. features ? 15kv (hbm) esd protected bus pins (rs-232 or rs-485) ? two independent ports, each user selectable for rs-232 (2 transceivers) or rs-485/422 (1 transceiver) ? flow-through pinouts simplify board layouts ? pb-free plus anneal available (rohs compliant) ? large (2.7v) differential v out for improved noise immunity in rs-485/422 networks ? full failsafe (open/short) rx in rs-485/422 mode ? loopback mode facilitates board self test functions ? user selectable rs-485 data rates (isl41334 only) - fast speed . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20mbps - slew rate limited. . . . . . . . . . . . . . . . . . . . . . . 460kbps - slew rate limited. . . . . . . . . . . . . . . . . . . . . . . 115kbps ? fast rs-232 data rate . . . . . . . . . . . . . . . up to 650kbps ? low current shutdown mode. . . . . . . . . . . . . . . . . . .42 a ? qfn package saves board space (isl41334 only) ? logic supply pin (v l ) eases operation in mixed supply systems (isl41334 only) applications ? gaming applications (e.g., slot machines) ? single board computers ? factory automation ? security networks ? industrial/process control networks ? level translators (e.g., rs-232 to rs-422) ? point of sale equipment ? dual channel rs-485 interfaces table 1. summary of features part number no. of ports package options rs-485 data rate (bps) rs-232 data rate (kbps) v l pin? active h or l rx enable? low power shutdown? isl81334 2 28 ld soic, 28 ld ssop 20m 650 no none yes isl41334 2 40 ld qfn (6 x 6mm) 20m, 460k, 115k 650 yes l yes data sheet december 20, 2005 caution: these devices are sensitive to electrosta tic discharge; follow proper ic handling procedures. 1-888-intersil or 1-888-468-3774 | intersil (and design) is a registered trademark of intersil americas inc. copyright ? intersil americas inc. 2005. all rights reserved. all other trademarks mentioned are the property of their respective owners.
2 fn6202.1 december 20, 2005 ordering information part number (note) part marking temp. range (c) package (pb-free) pkg. dwg. # isl81334iaz 81334iaz -40 to 85 28 ld ssop m28.209 isl81334iaz-t 81334iaz -40 to 85 28 ld ssop tape and reel m28.209 isl81334ibz isl81334ibz -40 to 85 28 ld soic m28.3 ISL81334IBZ-T isl81334ibz -40 to 85 28 ld soic tape and reel m28.3 isl41334irz 41334irz -40 to 85 40 ld qfn l40.6x6 isl41334irz-t 41334irz -40 to 85 40 ld qfn tape and reel l40.6x6 note: intersil pb-free plus anneal products employ special pb-free material sets; mo lding compounds/die attach materials and 100 % matte tin plate termination finish, which are rohs compliant and compatible with both snpb and pb-free soldering operations. intersil pb-free p roducts are msl classified at pb-free peak reflow temper atures that meet or exceed the pb-free requirements of ipc/jedec j std-020. pinouts isl81334 (soic, ssop) top view isl41334 (qfn) top view c1+ c1- v+ a1 b1 y1 z1 sel1 sel2 z2 y2 b2 a2 gnd c2+ v cc r b1 r a1 d z1 /de1 lb d y2 d z2 /de2 r a2 r b2 v- c2- d y1 on/off 28 27 26 25 24 23 22 21 20 19 18 17 16 15 1 2 3 4 5 6 7 8 9 10 11 12 13 14 1 40 2 3 4 5 6 7 8 9 10 30 29 28 27 26 25 24 23 22 21 39 38 37 36 35 34 33 32 31 11 12 13 14 15 16 17 18 19 20 nc nc nc c1- c1+ c2+ c2- v cc nc v l r b1 r a1 d z1 /de 1 d y1 lb d z2 /de 2 r a2 v+ a1 b1 y1 z1 sel1 sel2 z2 y2 b2 spa a2 rxen1 gnd spb gnd nc rxen2 v- nc on/off r b2 d y2 isl81334, isl41334
3 fn6202.1 december 20, 2005 table 2. isl81334 function table inputs receiver outputs driver outputs charge pumps (note 1) mode sel1 or 2 on/off de 1 or 2 r a r b yz 0 1 n.a. on on on on on rs-232 x 0 x high-z high-z high-z high-z off shutdown 1 1 0 on high-z * high-z high-z off rs-485 1 1 1 on high-z * on on off rs-485 note: 1. charge pumps are off iff sel1 = sel2 = 1, or if on/off = 0. if on = 1, and either port is programmed for rs-232 mode, then the charge pumps are on. isl81334 truth tables (for each port) rs-232 transmitting mode inputs outputs sel1 or 2 on/off d y d z yz 010011 010110 011001 011100 0 0 x x high-z high-z rs-232 receiving mode inputs output sel1 or 2 on/off abr a r b 010011 010110 011001 011100 0 1 open open 1 1 0 0 x x high-z high-z rs-485 transmitting mode inputs outputs sel1 or 2 on/off de1 or 2 d y yz 111010 111101 1 1 0 x high-z high-z 1 0 x x high-z high-z rs-485 receiving mode inputs output sel1 or 2 on/off b-a r a r b * 11 -40mv 1 high-z 11 -200mv 0 high-z 1 1 open or shorted together 1 high-z 1 0 x high-z high-z * internally pulled high through a 40k ? resistor. isl81334, isl41334
4 fn6202.1 december 20, 2005 table 3. isl41334 function table inputs receiver outputs driver outputs charge pumps (note 2) driver data rate (mbps) mode sel1 or 2 on/off spa spb rxen 1 or 2 de 1 or 2 r a r b yz 0 1 x x 0 n.a.onononon on 0.46 rs-232 0 1 x x 1 n.a. high-z high-z on on on 0.46 rs-232 x 0 x x x x high-z high-z high-z high-z off n.a. shutdown 1 1 x x 0 0 on high-z * high-z high-z off n.a. rs-485 1 1 0 0 0 1 on high-z * on on off 0.46 rs-485 1 1 0 1 0 1 on high-z * on on off 0.115 rs-485 1 1 1 0 0 1 on high-z * on on off 20 rs-485 1 1 1 1 0 1 on high-z * on on off 20 rs-485 1 1 x x 1 0 high-z high-z * high-z high-z off n.a. rs-485 1 1 0 0 1 1 high-z high-z * on on off 0.46 rs-485 1 1 0 1 1 1 high-z high-z * on on off 0.115 rs-485 1 1 1 0 1 1 high-z high-z * on on off 20 rs-485 1 1 1 1 1 1 high-z high-z * on on off 20 rs-485 note: 2. charge pumps are off iff sel1 = sel2 = 1, or if on/off = 0. if on = 1, and either port is programmed for rs-232 mode, then the charge pumps are on. isl41334 truth tables (for each port) rs-232 transmitting mode inputs outputs sel1 or 2 on/off d y d z yz 0 10011 0 10110 0 11001 0 11100 0 0 x x high-z high-z rs-232 receiving mode inputs output sel1 or 2 on/off rxen 1 or 2 a b r a r b 0 1 00011 0 1 00110 0 1 01001 0 1 01100 0 1 0 open open 1 1 0 1 1 x x high-z high-z 0 0 x x x high-z high-z rs-485 transmitting mode inputs outputs data rate sel1 or 2 on/ off den 1 or 2 spa spb d y yzmbps 1 1 1 0 0 0/1 1/0 0/1 0.46 1 1 1 0 1 0/1 1/0 0/1 0.115 1 1 1 1 x 0/1 1/0 0/1 20 1 1 0 x x x high-z high-z n.a. 1 0 x x x x high-z high-z n.a. rs-485 receiving mode inputs output sel1 or 2 on/off rxen 1 or 2 b-a r a r b * 110 -40mv 1 high-z 110 -200mv 0 high-z 1 1 0 open or shorted together 1 high-z 1 1 1 x high-z high-z 1 0 x x high-z high-z * internally pulled high through a 40k ? resistor. isl81334, isl41334
5 fn6202.1 december 20, 2005 pin descriptions pin mode function gnd both ground connection. lb both enables loopback mode when low. internally pulled-high. nc both no connection. on/off both if either port is in rs-232 mode, a low on on/off disables the charge pumps. in either mode, a low disables all the outputs, and places the device in low power shutdown. inte rnally pulled-high. on = 1 for normal operation. rxen both active low receiver output enable. rx is enabled when rxen is low; rx is high impedance when rxen is high. internally pulled low. (qfn only) sel both interface mode select input. high puts corresponding port in rs-485 mode, while a low puts it in rs-232 mode. v cc both system power supply input (5v). v l both logic-level supply. all ttl/cmos inputs and outputs are powered by this supply. (qfn only) a rs-232 receiver input with 15kv esd protection. a low on a forces r a high; a high on a forces r a low. rs-485 inverting receiver input with 15kv esd protection. b rs-232 receiver input with 15kv esd protection. a low on b forces r b high; a high on b forces r b low. rs-485 noninverting receiver input with 15kv esd protection. d y rs-232 driver input. a low on d y forces output y high. similarly, a high on d y forces output y low. rs-485 driver input. a low on d y forces output y high and output z low. similarly, a high on d y forces output y low and output z high. d z rs-232 driver input. a low on d z forces output z high. similarly, a high on d z forces output z low. de rs-485 driver output enable. the driver outputs, y and z, are e nabled by bringing de high. they are high impedance when de is low. internally pulled high when port selected for rs-485 mode. r a rs-232 receiver output. rs-485 receiver output: if b > a by at least -40mv, r a is high; if b < a by -200mv or more, r a is low; r a = high if a and b are unconnected (floating) or shorted together (i.e., full fail-safe). r b rs-232 receiver output. rs-485 not used. internally pulled-high, and unaffected by rxen . y rs-232 driver output with 15kv esd protection. rs-485 inverting driver output with 15kv esd protection. z rs-232 driver output with 15kv esd protection. rs-485 noninverting driver output with 15kv esd protection. sp rs-485 speed control. internally pulled-high. (qfn only) c1+ rs-232 external capacitor (voltage doubler) is connected to this lead. not needed if both ports in rs-485 mode. c1- rs-232 external capacitor (voltage doubler) is connected to this lead. not needed if both ports in rs-485 mode. c2+ rs-232 external capacitor (voltage inverter) is connec ted to this lead. not needed if both ports in rs-485 mode. c2- rs-232 external capacitor (voltage inverter) is connec ted to this lead. not needed if both ports in rs-485 mode. v+ rs-232 internally generated positive rs-232 transmitter supply (+5.5v). c3 not needed if both ports in rs-485 mode. v- rs-232 internally generated negative rs- 232 transmitter supply (-5.5v). c4 not needed if both ports in rs-485 mode. isl81334, isl41334
6 fn6202.1 december 20, 2005 typical operating circuit rs-232 mode without loopback rs-485 mode without loopback rs-232 mode with loopback rs-485 mode with loopback 26 v cc y1 z1 d y1 d z1 0.1 f + 0.1 f + 0.1 f 22 23 6 7 1 2 3 15 v+ v- c1+ c1- c2+ c2- + 0.1 f 28 27 r a1 a1 4 5k ? r b1 b1 525 5k ? c 1 c 2 + c 3 c 4 gnd +5v + 0.1 f 14 sel1 on/off 820 v cc note: pinout for soic and ssop 24 lb 21 v cc same for port 2. r r d d 26 v cc y1 z1 d y1 0.1 f + 0.1 f + 0.1 f 22 6 7 1 2 3 15 v+ v- c1+ c1- c2+ c2- + 0.1 f 28 27 r a1 a1 4 r b1 b1 5 25 c 1 c 2 + c 3 c 4 lb 21 gnd +5v + 0.1 f 14 sel1 820 v cc v cc de1 23 v cc note: pinout for soic and ssop 24 d r v cc on/off same for port 2. 26 v cc y1 z1 d y1 d z1 0.1 f + 0.1 f + 0.1 f 22 23 6 7 1 2 3 15 v+ v- c1+ c1- c2+ c2- + 0.1 f 28 27 r a1 5k ? r b1 25 5k ? c 1 c 2 + c 3 c 4 gnd +5v + 0.1 f 14 sel1 on/off 8 20 v cc note: pinout for soic and ssop 24 lb 21 gnd same for port 2. r r d d a1 4 b1 5 lb rx 26 v cc y1 z1 d y1 0.1 f + 0.1 f + 0.1 f 22 6 7 1 2 3 15 v+ v- c1+ c1- c2+ c2- + 0.1 f 28 27 r a1 r b1 25 c 1 c 2 + c 3 c 4 lb 21 gnd +5v + 0.1 f 14 sel1 820 v cc gnd de1 23 v cc note: pinout for soic and ssop 24 d r v cc on/off same for port 2. a1 4 b1 5 lb rx isl81334, isl41334
7 fn6202.1 december 20, 2005 absolute m aximum ratings (t a = 25c) thermal information v cc to ground. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7v v l (qfn only) . . . . . . . . . . . . . . . . . . . . . . . . . -0.5v to v cc + 0.5v input voltages all except a, b (non-qfn package) . . . . . -0.5v to (v cc + 0.5v) all except a, b (qfn package) . . . . . . . . . . -0.5v to (v l + 0.5v) input/output voltages a, b (any mode) . . . . . . . . . . . . . . . . . . . . . . . . . . . . -25v to +25v y, z (any mode, note 3) . . . . . . . . . . . . . . . . . . . -12.5v to +12.5v r a , r b (non-qfn package). . . . . . . . . . . . -0.5v to (v cc + 0.5v) r a , r b (qfn package) . . . . . . . . . . . . . . . . -0.5v to (v l + 0.5v) output short circuit duration y, z , r a , r b . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . indefinite esd rating . . . . . . . . . . . . . . . . . . . . . . . . . see specification table thermal resistance (typical, note 4) ja (c/w) 28 ld soic package . . . . . . . . . . . . . . . . . . . . . . . . 65 28 ld ssop package . . . . . . . . . . . . . . . . . . . . . . . 60 40 ld qfn package. . . . . . . . . . . . . . . . . . . . . . . . . 32 maximum junction temperature (plastic package) . . . . . . . 150c maximum storage temperature range . . . . . . . . . . . -65c to 150c maximum lead temperature (soldering 10s) . . . . . . . . . . . . 300c (soic and ssop - lead tips only) operating conditions temperature range . . . . . . . . . . . . . . . . . . . . . . . . . . . -40c to 85c caution: stresses above those listed in ?absolute maximum ratings? may cause permanent damage to the device. this is a stress o nly rating and operation of the device at these or any other conditions above those indicated in the operational sections of this specification is not implied. notes: 3. one output at a time, i out 100ma for 10 mins. 4. qfn ja is measured in free air with the component mounted on a high effe ctive thermal conductivity test board with ?direct attach? fe atures. ja for other packages is measured with the component mounted on a high effective thermal conductivity test board in free air. see te c h b r i e f tb379 and tech brief tb389 for details. electrical specifications test conditions: v cc = 4.5v to 5.5v, c1 - c4 = 0.1 f, v l = v cc (for qfn only); unless otherwise specified. typicals are at v cc = 5v, t a = 25c (note 5) parameter symbol test conditions temp (c) min typ max units dc characteristics - rs-485 driver (sel = v cc ) driver differential v out (no load) v od1 full - - v cc v driver differential v out (with load) v od2 r = 50 ? (rs-422) (figure 1) full 2.5 3.1 - v r = 27 ? (rs-485) (figure 1) full 2.2 2.7 5 v v od3 r d = 60 ? , r = 375 ? , v cm = -7v to 12v (figure 1) full 2 2.7 5 v change in magnitude of driver differential v out for complementary output states ? v od r = 27 ? or 50 ? (figure 1) full - 0.01 0.2 v driver common-mode v out v oc r = 27 ? or 50 ? (figure 1) (note 9) full - - 3.1 v change in magnitude of driver common-mode v out for complementary output states ? v oc r = 27 ? or 50 ? (figure 1) (note 9) full - 0.01 0.2 v driver short-circuit current, v out = high or low i os -7v (v y or v z ) 12v (note 7) full 35 - 250 ma driver three-state output leakage current (y, z) i oz outputs disabled, v cc = 0v or 5.5v v out = 12v full - - 500 a v out = -7v full -200 - - a dc characteristics - rs-232 driver (sel = gnd) driver output voltage swing v o all t outs loaded with 3k ? to ground full 5.0 +6/-7 - v driver output short-circuit current i os v out = 0v full -60 25/-35 60 ma dc characteristics - logic pins (i.e., driver and control input pins) input high voltage v ih1 v l = v cc if qfn full 2 1.6 - v v ih2 v l = 3.3v (qfn only) full 2 1.2 - v v ih3 v l = 2.5v (qfn only) full 1.5 1 - v isl81334, isl41334
8 fn6202.1 december 20, 2005 input low voltage v il1 v l = v cc if qfn full - 1.4 0.8 v v il2 v l = 3.3v (qfn only) full - 1 0.7 v v il3 v l = 2.5v (qfn only) full - - 0.5 v input current i in1 pins without pull-ups or pull-downs full -2 - 2 a i in2 lb , on/off , de, sp (qfn), rxen (qfn) full -25 - 25 a dc characteristics - rs-485 receiver inputs (sel = v cc ) receiver differential threshold voltage v th -7v v cm 12v, full failsafe full -0.2 - -0.04 v receiver input hysteresis ? v th v cm = 0v 25 - 35 - mv receiver input current (a, b) i in v cc = 0v or 4.5 to 5.5v v in = 12v full - - 0.8 ma v in = -7v full -0.64 - - ma receiver input resistance r in -7v v cm 12v, v cc = 0 (note 8) or 4.5v v cc 5.5v full 15 - - k ? dc characteristics - rs-232 receiver inputs (sel = gnd) receiver input voltage range v in full -25 - 25 v receiver input threshold v il full - 1.4 0.8 v v ih full 2.4 1.9 - v receiver input hysteresis ? v th 25 - 0.5 - v receiver input resistance r in v in = 15v, v cc powered up (note 8) full 3 5 7 k ? dc characteristics - receiver outputs (485 or 232 mode) receiver output high voltage v oh1 i o = -2ma (v l = v cc if qfn) full 3.5 4.6 - v v oh2 i o = -650 a, v l = 3v, qfn only full 2.6 2.9 - v v oh3 i o = -500 a, v l = 2.5v, qfn only full 2 2.4 - v receiver output low voltage v ol i o = 3ma full - 0.1 0.4 v receiver short-circuit current i osr 0v v o v cc full 7 - 85 ma receiver three-state output current i ozr output disabled, 0v v o v cc (or v l for qfn) full - - 10 a unused receiver (r b ) pull-up resistance r obz on/off = v cc , selx = v cc (rs-485 mode) 25 - 40 - k ? power supply characteristics no-load supply current, note 6 i cc232 sel1 or sel2 = gnd, lb = on/off = v cc full - 3.7 7 ma i cc485 sel 1 & 2 = lb = de = on/off = v cc full - 1.6 5 ma shutdown supply current i shdn232 on/off = selx = gnd, lb = v cc , (spx = v cc if qfn) full - 25 50 a i shdn485 on/off = dex = gnd, selx = lb = v cc , (spx = gnd if qfn) soic/ssop full - 42 80 a qfn full - 80 160 a esd characteristics bus pins (a, b, y, z) any mode human body model 25 - 15 - kv all other pins human body model 25 - 4 - kv electrical specifications test conditions: v cc = 4.5v to 5.5v, c1 - c4 = 0.1 f, v l = v cc (for qfn only); unless otherwise specified. typicals are at v cc = 5v, t a = 25c (note 5) (continued) parameter symbol test conditions temp (c) min typ max units isl81334, isl41334
9 fn6202.1 december 20, 2005 rs-232 driver and receiver switching characteri stics (sel = gnd, all versions and speeds) driver output transition region slew rate sr r l =3k ?, measured from 3v to -3v or -3v to 3v c l 15pf full - 18 30 v/ s c l 2500pf full 4 12 - v/ s driver output transition time t r , t f r l =3k ? , c l = 2500pf, 10% - 90% full 0.22 1.2 3.1 s driver propagation delay t dphl r l =3k ?, c l = 1000pf (figure 6) full - 1 2 s t dplh full - 1.2 2 s driver propagation delay skew t dskew t dphl - t dplh (figure 6) full - 240 400 ns driver enable time from shutdown t densd v out = 3.0v 25 - 20 - s driver maximum data rate dr d r l =3k ?, c l = 1000pf, one transmitter switching per port full 460 650 - kbps receiver propagation delay t rphl c l = 15pf (figure 7) full - 50 120 ns t rplh full - 40 120 ns receiver propagation delay skew t rskew t rphl - t rplh (figure 7) full - 10 40 ns receiver maximum data rate dr r c l = 15pf full 0.46 2 - mbps rs-485 driver switching characteristics (fast data rate (20mbps), sel = v cc , all versions (spa = v cc if qfn)) driver differential input to output delay t dlh , t dhl r diff = 54 ? , c l = 100pf (figure 2) full 15 30 50 ns driver output skew t skew r diff = 54 ? , c l = 100pf (figure 2) full - 0.5 10 ns driver differential rise or fall time t r , t f r diff = 54 ? , c l = 100pf, figure 2 full 3 11 20 ns driver enable to output low t zl c l = 100pf, sw = v cc (figure 3) full - 27 60 ns driver enable to output high t zh c l = 100pf, sw = gnd (figure 3) full - 24 60 ns driver disable from output low t lz c l = 15pf, sw = v cc (figure 3) full - 31 60 ns driver disable from output high t hz c l = 15pf, sw = gnd (figure 3) full - 24 60 ns driver enable from shutdown to output low t zl(shdn) r l = 500 ? , c l = 100pf, sw = v cc (figure 3) full - 65 250 ns driver enable from shutdown to output high t zh(shdn) r l = 500 ? , c l = 100pf, sw = gnd (figure 3) full - 152 250 ns driver maximum data rate f max r diff = 54 ? , c l = 100pf (figure 2) full - 30 - mbps rs-485 driver switching characteristics (medium data rate (460kbps, qfn only), sel = v cc , spa = spb= gnd) driver differential input to output delay t dlh , t dhl r diff = 54 ? , c l = 100pf (figure 2) full 200 490 1000 ns driver output skew t skew r diff = 54 ? , c l = 100pf (figure 2) full - 110 400 ns driver differential rise or fall time t r , t f r diff = 54 ? , c l = 100pf (figure 2) full 300 600 1100 ns driver enable to output low t zl c l = 100pf, sw = v cc (figure 3) full - 30 300 ns driver enable to output high t zh c l = 100pf, sw = gnd (figure 3) full - 128 300 ns driver disable from output low t lz c l = 15pf, sw = v cc (figure 3) full - 31 60 ns driver disable from output high t hz c l = 15pf, sw = gnd (figure 3) full - 24 60 ns driver enable from shutdown to output low t zl(shdn) r l = 500 ? , c l = 100pf, sw = v cc (figure 3) full - 65 500 ns driver enable from shutdown to output high t zh(shdn) r l = 500 ? , c l = 100pf, sw = gnd (figure 3) full - 255 500 ns electrical specifications test conditions: v cc = 4.5v to 5.5v, c1 - c4 = 0.1 f, v l = v cc (for qfn only); unless otherwise specified. typicals are at v cc = 5v, t a = 25c (note 5) (continued) parameter symbol test conditions temp (c) min typ max units isl81334, isl41334
10 fn6202.1 december 20, 2005 driver maximum data rate f max r diff = 54 ? , c l = 100pf (figure 2) full - 2000 - kbps rs-485 driver switching characteristics (slow data rate (115kbps, qfn only), sel = v cc , spa = gnd, spb= v cc ) driver differential input to output delay t dlh , t dhl r diff = 54 ? , c l = 100pf (figure 2) full 800 1500 2500 ns driver output skew t skew r diff = 54 ? , c l = 100pf (figure 2) full - 350 1250 ns driver differential rise or fall time t r , t f r diff = 54 ? , c l = 100pf (figure 2) full 1000 2000 3100 ns driver enable to output low t zl c l = 100pf, sw = v cc (figure 3) full - 32 600 ns driver enable to output high t zh c l = 100pf, sw = gnd (figure 3) full - 300 600 ns driver disable from output low t lz c l = 15pf, sw = v cc (figure 3) full - 31 60 ns driver disable from output high t hz c l = 15pf, sw = gnd (figure 3) full - 24 60 ns driver enable from shutdown to output low t zl(shdn) r l = 500 ? , c l = 100pf, sw = v cc (figure 3) full - 65 800 ns driver enable from shutdown to output high t zh(shdn) r l = 500 ? , c l = 100pf, sw = gnd (figure 3) full - 420 800 ns driver maximum data rate f max r diff = 54 ? , c l = 100pf (figure 2) full - 800 - kbps rs-485 receiver switching characteristics (sel = v cc , all versions and speeds) receiver input to output delay t plh , t phl (figure 4) full 20 50 90 ns receiver skew | t plh - t phl |t skew (figure 4) full - 0.1 10 ns receiver maximum data rate f max full - 40 - mbps receiver enable/disable characteristics (all modes and speeds) receiver enable to output low t zl qfn only, c l = 15pf, sw = v cc (figure 5) full - 22 60 ns receiver enable to output high t zh qfn only, c l = 15pf, sw = gnd (figure 5) full - 23 60 ns receiver disable from output low t lz qfn only, c l = 15pf, sw = v cc (figure 5) full - 24 60 ns receiver disable from output high t hz qfn only, c l = 15pf, sw = gnd (figure 5) full - 25 60 ns receiver enable from shutdown to output low t zlshdn c l = 15pf, sw = v cc (figure 5) rs-485 mode full - 260 700 ns rs-232 mode 25 - 35 - ns receiver enable from shutdown to output high t zhshdn c l = 15pf, sw = gnd (figure 5) rs-485 mode full - 260 700 ns rs-232 mode 25 - 25 - ns notes: 5. 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. 6. supply current specification is valid for l oaded drivers when de = 0v (rs-485 mode only). 7. applies to peak current. see ?typical performance curves? for more information. 8. r in defaults to rs-485 mode (>15k ? ) when the device is unpowered (v cc = 0v), regardless of the state of the sel inputs. 9. v cc 5.25v. electrical specifications test conditions: v cc = 4.5v to 5.5v, c1 - c4 = 0.1 f, v l = v cc (for qfn only); unless otherwise specified. typicals are at v cc = 5v, t a = 25c (note 5) (continued) parameter symbol test conditions temp (c) min typ max units isl81334, isl41334
11 fn6202.1 december 20, 2005 test circuits and waveforms figure 1. rs-485 driver v od and v oc test circuit figure 2a. test circuit figure 2b. measurement points figure 2. rs-485 driver propagation delay and differential transition times d de d y v cc v od v oc r r y z r d d de d y v cc signal generator c l = 100pf r diff y z c l = 100pf out (z) 3v 0v t plh 1.5v 1.5v v oh v ol 50% 50% t phl out (y) t phl v oh v ol 50% 50% t plh diff out (z - y) t r +v od -v od 90% 90% t f 10% 10% d y skew = |t plh (y or z) - t phl (z or y)| 0v 0v t dhl t dlh isl81334, isl41334
12 fn6202.1 december 20, 2005 figure 3a. test circuit figure 3b. measurement points figure 3. rs-485 driver enable and disable times figure 4a. test circuit figure 4b. measurement points figure 4. rs-485 receiver propagation delay figure 5a. test circuit figure 5b. measurement points figure 5. rs-485 receiver enable and disable times test circuits and waveforms (continued) d de dy c l 500 ? y z v cc gnd sw for shdn tests, switch on/off rather than de parameter on/de output dy sw c l (pf) t hz 1/- y/z 0/1 gnd 15 t lz 1/- y/z 1/0 v cc 15 t zh 1/- y/z 0/1 gnd 100 t zl 1/- y/z 1/0 v cc 100 t zh(shdn) -/1 y/z 0/1 gnd 100 t zl(shdn) -/1 y/z 1/0 v cc 100 signal generator out (y, z) 3v 0v 1.5v 1.5v v oh 0v 2.3v v oh - 0.5v t hz out (y, z) v cc v ol 2.3v v ol + 0.5v t lz de output high output low t zl t zh t zh(shdn) t zl(shdn) (on/off for shdn) enabled signal generator r r a rxen (qfn only) b a 0v 15pf r a +1.5v -1.5v t plh 0v 0v v cc 0v 1.5v 1.5v t phl b 1k ? v cc gnd sw for shdn tests, switch on/off rather than rxen parameter on/rxen bsw t hz (qfn only) 1/- +1.5v gnd t lz (qfn only) 1/- -1.5v v cc t zh (qfn only) 1/- +1.5v gnd t zl (qfn only) 1/- -1.5v v cc t zh(shdn) -/0 +1.5v gnd t zl(shdn) -/0 -1.5v v cc signal generator r r a b a 15pf rxen (qfn only) r a 3v 0v 1.5v 1.5v v oh 0v 1.5v v oh - 0.5v t hz r a v cc v ol 1.5v v ol + 0.5v t lz rxen (qfn only) output high output low t zl t zh t zl(shdn) t zh(shdn) 3v 0v 1.5v on/off (for shdn tests) enabled isl81334, isl41334
13 fn6202.1 december 20, 2005 figure 6a. test circuit figure 6b. measurement points figure 6. rs-232 driver propagation delay and transition times figure 7a. test circuit figure 7b. measurement points figure 7. rs-232 receiver propagation delay and transition times test circuits and waveforms (continued) d de d y,z v cc signal generator r l y, z c l out (y,z) 3v 0v 1.5v 1.5v v o+ v o- 0v 0v d y,z skew = |t dphl - t dplh | t dphl t dplh r rxen a, b signal generator r a, r b c l = 15pf r a, r b 3v 0v t rphl 1.7v 1.3v v oh v ol 0.8v 2.4v t rplh a, b skew = |t rphl - t rplh | isl81334, isl41334
14 fn6202.1 december 20, 2005 typical application rs-232 to rs-485 converter the islx1334 are ideal for im plementing a single ic 2-wire (tx data, rx data) protocol c onverter, because each port can be programmed for a different prot ocol. figure 8 illustrates the simple connections to create a single transceiver rs-232 to rs-485 converter. depending on the rs-232 data rate, using an rs-422 bus as an rs-232 ?e xtension cord? can extend the transmission distance up to 4000? (1220m). a similar circuit on the other end of the cable completes the conversion to/from rs-232. detailed description each of the two islx1334 ports supports dual protocols: rs-485/422, and rs-232. rs-485 and rs-422 are differential (balanced) data transmission standards for use in high speed (up to 20mbps) networks, or long haul and noisy environments. the differential signaling, coupled with rs-485?s requirement for extended common mode range (cmr) of +12v to -7v make these transceivers extremely tolerant of ground potential differences, as well as voltages induced in the cable by external fields. both of these effects are real concerns when communicating over the rs-485/422 maximum distance of 4000? (1220m). it is important to note that the islx1334 don?t follow the rs-485 convention whereby the inverting i/o is labeled ?b/z?, and the noninverting i/o is ?a/y?. thus, in the application diagrams below the 1334 a/y (b/z) pins connect to the b/z (a/y) pins of the generic rs-485/422 ics. rs-422 is typically a point-to-point (one driver talking to one receiver on a bus), or a point-to-multipoint (multidrop) standard that allows only one driver and up to 10 receivers on each bus. because of the one driver per bus limitation, rs-422 networks use a two bus, full duplex structure for bidirectional communication, and the rx inputs and tx outputs (no tri-state required) connect to different busses, as shown in figure 10. conversely, rs-485 is a true multipoint standard, which allows up to 32 devices (any co mbination of drivers- must be tri-statable - and receivers) on each bus. now bidirectional communication takes place on a single bus, so the rx inputs and tx outputs of a port connect to the same bus lines, as shown in figure 9. each port set to rs-485 /422 mode includes one rx and one tx. 26 v cc y1 z1 d y1 d z1 0.1 f + 0.1 f + 0.1 f 22 23 6 7 1 2 3 15 v+ v- c1+ c1- c2+ c2- + 0.1 f 28 27 r a1 a1 4 5k ? r b1 b1 525 5k ? c 1 c 2 + c 3 c 4 gnd +5v + 0.1 f 14 sel1 on/off 8 20 v cc 24 r r d d note: pinout for soic and ssop y2 z2 d y2 19 11 10 de2 18 v cc d r a2 a2 13 b2 12 17 r sel2 9 v cc rs-232 in rs-232 out rs-485 in rs-485 out nc nc nc figure 8. single ic rs-232 to rs-485 converter txd rxd figure 9. typical half duplex rs-485 network 0.1 f + d r v cc gnd ra rxen * de dy y z +5v r t 0.1 f + d r v cc gnd ro re de di a/y b/z +5v 0.1 f + d v cc gnd ro re de di a/y b/z +5v r r t islx1334 generic 1/2 duplex 485 xcvr generic 1/2 duplex 485 xcvr tx/rx * qfn only a b isl81334, isl41334
15 fn6202.1 december 20, 2005 rs-232 is a point-to-point, singled ended (signal voltages referenced to gnd) communicat ion protocol targeting fairly short (<150?, 46m) and low data rate (<1mbps) applications. each port contains two transceivers (2 tx and 2 rx) in rs-232 mode. protocol selection is handled via a logic pin (selx) for each port. . islx1334 advantages these dual protocol ics offer many parametric improvements versus those offered on competing dual protocol devices. some of the major improvements are: 15kv bus pin esd - eases board level requirements; 2.7v diff v out - better noise immunity and/or distance; full failsafe rs-485 rx - eliminates bus biasing; selectable rs-485 data rate - up to 20mbps, or slew rate limited for low emi and fewer termination issues; high rs-232 data rate - >460kbps lower tx and rx skews - wider, consistent bit widths; lower i cc - max i cc is 2-4x lower than competition; flow-thru pinouts - tx, rx bus pins on one side/logic pins on the other, for easy routing to connector/uart; smaller (ssop and qfn) and pb-free packaging. rs-232 mode rx features rs-232 receivers invert and convert rs-232 input levels ( 3v to 25v) to the standard ttl/cmos levels required by a uart, asic, or controller serial port. receivers are designed to operate at faster da ta rates than the drivers, and they feature very low skews (10ns) so the receivers contribute negligibly to bit wi dth distortion. inputs include the standards required 3k ? to 7k ? pulldown resistor, so unused inputs may be left unconnected. rx inputs also have built-in hysteresis to increase noise immunity, and to decrease erroneous triggering due to slowly transitioning input signals. rx outputs are short circuit protected, and are only tri- statable when the entire ic is shutdown via the on/off pin, or via the active low rxen pin available on the qfn package option (see ?isl41334 special features? for more details). tx features rs-232 drivers invert and c onvert the standard ttl/cmos levels from a uart, or controller serial port to rs-232 compliant levels ( 5v minimum). the tx delivers these compliant output levels even at data rates of 650kbps, and with loads of 1000pf. the drivers are designed for low skew (typically 12% of the 500kbps bit width), and are compliant to the rs-232 slew rate spec (4 to 30v/ s) for a wide range of load capacitances. tx inputs float if left unconnected, and may cause i cc increases. for the best results, connect unused inputs to gnd. tx outputs are short circuit protected, and incorporate a thermal shdn feature to protec t the ic in situations of severe power dissipation. see the rs-485 section for more details. drivers tri-state only in shdn, or when the 5v power supply is off. the shdn function is useful for tri-stating the outputs if both ports will always be tri-stated together (e.g., used as a four transceiver rs-232 port), and if it is acceptable for the rx to be disabled as well. a single port tx disable can be accomplished by switching the port to rs-485 mode, and then using the corresponding de pin to tri-state the drivers. of course, the rx is now an rs-485 rx, so this option is feasible onl y if the rx aren?t needed when the tx are disabled. charge pumps the on-chip charge pumps create the rs-232 transmitter power supplies (typically +6/-7v) from a single supply as low as 4.5v, and are enabled only if either port is configured for rs-232 operation. the efficient design requires only four figure 10. typical rs-422 network 0.1 f + d r v cc gnd ra de dy b a +5v 0.1 f + d r v cc gnd ro di a z +5v 0.1 f + v cc gnd ro re +5v r r t islx1334 (master) generic 422 rx (slave) generic full duplex 422 xcvr (slave) a b r t y z y b 1k ? or nc isl81334, isl41334
16 fn6202.1 december 20, 2005 small 0.1 f capacitors for the voltage doubler and inverter functions. by operating discontinuously (i.e., turning off as soon as v+ and v- pump up to the nominal values), the charge pump contribution to rs-232 mode i cc is reduced significantly. unlike competin g devices that require the charge pump in rs-485 mode, disabling the charge pump saves power, and minimizes noise. if the application keeps both ports in rs-485 mode (e.g., a dedicated dual channel rs-485 interface), then the char ge pump capacitors aren?t even required. data rates and cabling drivers operate at data rates up to 650kbps, and are guaranteed for data rates up to 460kbps. the charge pumps and drivers are designed such that one driver in each port can be operated at the rated load, and at 460kbps (see figure 34). figure 34 also shows that drivers can easily drive several thousands of picofarads at data rates up to 250kbps, while still delivering compliant 5v output levels. receivers operate at data rates up to 2mbps. they are designed for a higher data rate to facilitate faster factory downloading of software into the final product, thereby improving the user?s manufacturing throughput. figures 37 and 38 illustrate driver and receiver waveforms at 250kbps, and 500kbps, respectively. for these graphs, one driver of each port drives the specified capacitive load, and a receiver in the port. rs-232 doesn?t require anything special for cabling; just a single bus wire per transmitter and receiver, and another wire for gnd. so an islx1334 rs-232 port uses a five conductor cable for interconnection. bus terminations are not required, nor allowed, by the rs-232 standard. rs-485 mode rx features rs-485 receivers convert differential input signals as small as 200mv, as required by the rs-485 and rs-422 standards, to ttl/cmos output levels. the differential rx provides maximum sensitivity, noise immunity, and common mode rejection. per the rs-485 standard, receiver inputs function with common mode voltages as great as 7v outside the power supplies (i.e., +12v and -7v), making them ideal for long networks where induced voltages are a realistic concern. each rs-485/422 port includes a single receiver (ra), and the unused rx output (rb) is disabled, but pulled high by an internal current source. the internal current source turns off in shdn. worst case receiver input currents are 20% lower than the 1 ?unit load? (1ma) rs-485 limit, which translates to a 15k ? minimum input resistance. these receivers include a ?fu ll fail-safe? function that guarantees a high level receiver output if the receiver inputs are unconnected (floating), shorte d together, or if the bus is terminated but undriven (i.e., differential voltage collapses to near zero due to termination). failsafe with shorted, or terminated and undriven inputs is accomplished by setting the rx upper switching point at -40mv, thereby ensuring that the rx recognizes a 0v differential as a high level. all the rx outputs are short circ uit protected, and are tri-state when the ic is forced into shdn, but isl81334 (soic and ssop) receiver outputs are not independently tri-statable. isl41334 (qfn) receiver outputs are tri-statable via an active low rxen input for each port (see ?isl41334 special features? for more details). tx features the rs-485/422 driver is a di fferential output device that delivers at least 2.2v across a 54 ? load (rs-485), and at least 2.5v across a 100 ? load (rs-422). both levels significantly exceed the stand ards requirements, and these exceptional output voltages increase system noise immunity, and/or allow for transmission over longer distances. the drivers feature low propagation delay skew to maximize bit widths, and to minimize emi. to allow multiple drivers on a bus, the rs-485 spec requires that drivers survive worst ca se bus contentions undamaged. the islx1334 drivers meet this requirement via driver output short circuit current limits, and on-chip thermal shutdown circuitry. the output stages incorporate current limiting circuitry that ensures that the output current never exceeds the rs-485 spec, even at the common mode voltage range extremes. in the event of a major short circuit condition, devices also include a thermal shutdown feature that disables the drivers whenever the die temperature becomes excessive. this elimi nates the power dissipation, allowing the die to cool. the drivers automatically re-enable after the die temperature drops about 15 degrees. if the contention persists, the ther mal shutdown/re-enable cycle repeats until the fault is cleare d. receivers stay operational during thermal shutdown. rs-485 multi-driver op eration also requires drivers to include tri-state functionality, so each port has a de pin to control this function. if the driver is used in an rs-422 network, such that driver tri-state isn?t required, then the de pin can be left unconnected and an internal pull-up keeps it in the enabled state. drivers are also tri-stated when the ic is in shdn, or when the 5v power supply is off. speed options the isl81334 (soic/ssop) has fixe d, high slew rate driver outputs optimized for 20mbps data rates. the isl41334 (qfn) offers three user selectab le data rate options: ?fast? for high slew rate and 20mbps; ?medium? with slew rate limiting set for 460kbps; ?slow? with even more slew rate limiting for 115kbps operation. see the ?data rate? and ?slew rate limited data rates? sections for more information. receiver performance is the same for all three speed options. isl81334, isl41334
17 fn6202.1 december 20, 2005 data rate, cables, and terminations rs-485/422 are intended for network lengths up to 4000? (1220m), but the maximum system data rate decreases as the transmission length increases. devices operating at the maximum data rate of 20mbps are limited to lengths of 20- 30? (6-9m), while devices operat ing at or below 115kbps can operate at the maximum length of 4000? (1220m). higher data rates require faster edges, so both the islx1334 versions offer an edge rate capable of 20mbps data rates. the isl41334 also offers two slew rate limited edge rates to minimize problems at slower data rates. nevertheless, for the best ji tter performance when driving long cables, the faster speed settings may be preferable, even at low data rates. see the ?rs-485 slew rate limited data rates? section for details. twisted pair is the cable of choice for rs-485/422 networks. twisted pair cables tend to pick up noise and other electromagnetically induce d voltages as common mode signals, which are effectively rejected by the differential receivers in these ics. the preferred cable connect ion technique is ?daisy- chaining?, where the cable runs from the connector of one device directly to the connector of the next device, such that cable stub lengths are negligib le. a ?backbone? structure, where stubs run from the main backbone cable to each device?s connector, is the next best choice, but care must be taken to ensure that each stub is electrically ?short?. see table 4 for recommended maximum stub lengths for each speed option. proper termination is imperative to minimize reflections when using the 20mbps speed option. short networks using the medium and slow speed options need not be terminated, but terminations are recommended unless power dissipation is an overriding concern. note that the rs-485 spec allows a maximum of two terminations on a network, otherwise the tx output voltage may not meet the required v od . in point-to-point, or point-to -multipoint (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 cable should be kept as short as possible, but definitely shorter than the limits shown in table 4. multipoint (rs-485) systems require that the main cable be terminated in its characteri stic impedance at both ends. again, keep stubs connecting a transceiver to the main cable as short as possible, and refer to table 4. avoid ?star?, and other configurations, wh ere there are many ?ends? which would require more than the two allowed terminations to prevent reflections. high esd all pins on the islx1334 include esd protection structures rated at 4kv (hbm), which is good enough to survive esd events commonly seen during manufacturing. but the bus pins (tx outputs and rx inputs) are particularly vulnerable to esd events because they connect to an exposed port on the exterior of the finished product. simply touching the port pins, or connecting a cable, can destroy an unprotected port. islx1334 bus pins are fitted with advanced structures that deliver esd protection in excess of 15kv (hbm), without interfering with any signal in the rs-485 or the rs-232 range. this high level of protection may eliminate the need for board level protection, or at the very least will increase the robustness of any board level scheme. small packages many competing dual protocol ics are available only in monstrously large 24 to 28 ld soic packages. the isl81334?s 28 ld ssop is 50% smaller than even a 24 ld soic, and the isl41334?s tiny 6x6mm qfn is 80% smaller than a 28 ld soic. flow through pinouts even the islx1334 pinouts are f eatures, in that the ?flow- through? design simplifies board layout. having the bus pins all on one side of the package for easy routing to a cable connector, and the rx outputs and tx inputs on the other side for easy connection to a uart, avoids costly and problematic crossovers. figure 11 illustrates the flow- through nature of the pinout. low power shutdown (shdn) mode the on/off pin is driven low to place the ic (both ports) in the shdn mode, and the already low supply current drops to as low as 25 a. if this functionality isn?t desired, the pin can be left disconnected (thanks to the internal pull-up), or it should be connected to v cc (v l for the qfn), through a 1k ? resistor. shdn disables the tx and rx outputs, and table 4. recommended stub lengths speed option maximum stub length ft (m) slow 350-500 (107-152) med 100-150 (30.5 - 46) fast 1-3 (0.3 - 0.9) uart or asic or controller ra2 dy2 ra1 dy1 z2 y2 y1 z1 a1 b1 a2 b2 connector isl81334 figure 11. illustration of flow through pinout d r isl81334, isl41334
18 fn6202.1 december 20, 2005 disables the charge pumps if either port is in rs-232 mode, so v+ collapses to v cc , and v- collapses to gnd. all but 5ua of shdn i cc current is due to control input (on, lb , sp, de) pull-up resistors (~20 a/resistor), so shdn i cc varies depending on the islx1334 configuration. the spec tables indicate the worst case values, but careful selection of the configuration yields lower currents. for example, in rs- 232 mode the sp pins aren?t used, so if both ports are configured for rs-232, floating or tying the sp pins high minimizes shdn i cc . likewise in rs-485 mode, the drivers are disabled in shdn, so driving the de pins high during this time also reduces i cc . on the isl41334, the shdn i cc increases as v l decreases. v l powers the input stage and sets its v oh at v l rather than v cc . v cc powers the second stage, but the second stage input isn?t driven to the rail, so some i cc current flows. see figure 21 for details. when enabling from shdn in rs-232 mode, allow at least 20 s for the charge pumps to stabilize before transmitting data. the charge pumps aren?t used in rs-485 mode, so the transceiver is ready to send or receive data in less than 1 s, which is much faster than competing devices that require the charge pump for all modes of operation. internal loopback mode driving the lb pin low places both ports in the loopback mode, a mode that facilitates im plementing board level self test functions. in loopback, internal switches disconnect the rx inputs from the rx outputs, and feed back the tx outputs to the appropriate rx output. th is way the data driven at the tx input appears at the corresponding rx output (refer to ?typical operating circuits?). the tx outputs remain connected to their terminals, so the external loads are reflected in the loopback performance. this allows the loopback function to potentially detect some common bus faults such as one or both dr iver outputs shorted to gnd, or outputs shorted together. note that the loopback mode uses an additional set of receivers, as shown in the ?t ypical operating circuits?. these loopback receivers are not standards compliant, so the loopback mode can?t be used to implement a half-duplex rs-485 transceiver. if loopback won?t be utilized, the pin can be left disconnected (thanks to the internal pull-up), or it should be connected to v cc (v l for the qfn), through a 1k ? resistor. isl41334 (qfn package) special features logic supply (v l pin) the isl41334 (qfn) includes a v l pin that powers the logic inputs (tx inputs and control pins) and rx outputs. these pins interface with ?logic? devices such as uarts, asics, and controllers, and today most of these devices use power supplies significantly lower than 5v. thus, a 5v output level from a 5v powered dual protocol ic might seriously overdrive and damage the logic device input. similarly, the the logic device?s low v oh might not exceed the v ih of a 5v powered dual protocol input. connecting the v l pin to the power supply of the logic device - as shown in figure 12 - limits the isl41334?s rx output v oh to v l (see figure 15), and reduces the tx and control input switching points to values compatible with the logic device output levels. tailoring the logic pin input switching points and output levels to the supply voltage of the uart, asic, or controller eliminates the need for a level shifter/translator between the two ics. v l can be anywhere from v cc down to 1.65v, but the input switching points may not provide enough noise margin when v l < 1.8v. table 5 indicates typical v ih and v il values for various v l values so the user can ascertain whether or not a particular v l voltage meets his needs. table 5. v ih and v il vs. v l for v cc = 5v v l (v) v ih (v) v il (v) 1.65v 0.79 0.50 1.8v 0.82 0.60 2.0v 0.87 0.69 2.5v 0.99 0.86 3.3v 1.19 1.05 figure 12. using v l pin to adjust logic levels gnd r xd t xd v cc = +2v uart/processor gnd r a d y v cc = +5v isl81334 v oh 2v v oh = 5v v ih 2v esd diode gnd r xd t xd v cc = +2v uart/processor gnd r a d y v cc = +5v isl41334 v oh 2v v oh = 2v v ih = 0.9v esd diode v l isl81334, isl41334
19 fn6202.1 december 20, 2005 the v l supply current (i l ) is typically less than 100 a, as shown in figures 20 and 21. all of the dc v l current is due to inputs with internal pull-up resistors (de, sp, lb , on/off ) being driven to the low input state. the worst case i l current occurs during shdn (see figure 20), due to the i l through the on/off pin pull-up resistor when that pin is driven low. i il through an input pull-up resistor is ~20 a, so the i l in figure 20 drops by about 40 a (at v l = 5v) when the two sp inputs are high (middle vs. top curve). i l is lowest in the rs-232 mode, because only the on/off pin should be driven low. when all these inputs are driven high, i l drops to <1 a, so to minimize power dissipation drive these inputs high when unneeded (e.g., sp inputs aren?t used in rs-232 mode, so drive them high). active low rx enable (rxen) in many rs-485 applications, especially half duplex configurations, users like to accomplish ?echo cancellation? by disabling the corresponding receiver while its driver is transmitting data. this func tion is available on the qfn package via an active low rxen pin for each port. the active low function also simp lifies direction control, by allowing a single tx/rx direction control line. if an active high rxen were used, either two valuable i/o pins would be used for direction control, or an external inverter is required between de and rxen. figure 13 details the advantage of using the rxen pin. rs-485 slew rate limited data rates the soic and ssop versions of this ic operate with tx output transitions optimized for a 20mbps data rate. these fast edges may increase emi and reflection issues, even though fast transitions aren?t required at the lower data rates used by many applications. the isl41334 (qfn version) solves this problem by offering two additional, slew rate limited, data rates that are optimized for speeds of 115kbps, and 460kbps.the slew limited edges permit longer unterminated networks, or longer stubs off terminated busses, and help minimize emi and reflections. nevertheless, for the best jitter performance when driving long cables, the faster speed options may be preferable, even at lower data rates. the fa ster output transitions deliver less variability (jitter) when loaded with the large capacitance associated with long cables. figures 43, 44, and 45 detail the jitter performance of the three speed options while driving three different cable l engths. the figures show that under all conditions the faster the edge rate, the better the jitter performance. of course, fa ster transitions require more attention to ensuring shor t stub lengths, and quality terminations, so there are trade- offs to be made. assuming a jitter budget of 10%, it is likely better to go with the slow speed option for data rates of 115kbps or less, to minimize fast edge effects. likewise, the medium speed option is a good choice for data rates between 115kbps and 460kbps. for higher data rates, or w hen the absolute best jitter is required, use the high speed option. speed selection is via the sp a and spb pins (see table 3), and the selection pertains to each port programmed for rs-485 mode. evaluation board an evaluation board, part number isl41334eval1, is available to assist in assessing the dual protocol ic?s performance. the evaluation board contains a qfn packaged device, but because the same die is used in all packages, the board is also useful for evaluating the functionality of the other versions. the board?s design allows for evaluation of all standard f eatures, plus the qfn specific features. refer to the eval board application note for details, and contact your sales rep for ordering information. figure 13. using active low vs active high rx enable 0.1 f + d r v cc gnd ra rxen den dy +5v isl81387 tx/rx active high rx enable 0.1 f + d r v cc gnd ra rxen * de dy +5v isl41334 tx/rx * qfn only active low rx enable y z a b y z a b isl81334, isl41334
20 fn6202.1 december 20, 2005 typical performance curves v cc = v l = 5v, t a = 25c; unless otherwise specified figure 14. receiver output current vs receiver output voltage figure 15. receiver high output voltage vs logic supply voltage (v l ) figure 16. rs-485, driver output current vs differential output voltage figure 17. rs-485, driver differential output voltage vs temperature figure 18. rs-485, driver output current vs short circuit voltage figure 19. supply current vs temperature 012345 0 10 20 30 40 50 receiver output voltage (v) receiver output current (ma) v oh , 25 c v oh , 85 c v ol , 25 c v ol , 85 c v l (v) high output voltage (v) 012345 0 1 2 3 4 5 i oh = -1ma i oh = -4ma i oh = -8ma differential output voltage (v) driver output current (ma) 012345 0 10 20 30 40 50 60 70 80 90 100 -40 0 50 85 temperature (c) differential output voltage (v) -25 25 75 r diff = 54 ? r diff = 100 ? 3 3.1 3.2 3.3 3.4 3.5 3.6 output voltage (v) -7 -6 -4 -2 0 2 4 6 8 10 12 output current (ma) -150 -100 -50 0 50 100 150 y or z = high y or z = low 25c 85c -40c full temp range -40 0 50 85 temperature (c) i cc (ma) -25 25 75 1 1.5 2 2.5 3 3.5 4 rs-232, rxen = x rs-485, de = gnd, rxen = x rs-485, half duplex, de = v cc , rxen = x rs-485, full duplex, de = v cc , rxen = x isl81334, isl41334
21 fn6202.1 december 20, 2005 figure 20. rs-232, v l supply current vs v l voltage (qfn only) figure 21. v cc and v l shdn supply currents vs v l voltage (qfn only) figure 22. rs-485, driver propagation delay vs temperature (slow data rate, qfn only) figure 23. rs-485, driver skew vs temperature (slow data rate, qfn only) typical performance curves v cc = v l = 5v, t a = 25c; unless otherwise specified (continued) i l (a) v l (v) 1 10 100 10m 1m 23456 v l v cc v l > v cc no load v in = v l or gnd lb = v l rs-232, on = gnd, sp = v l rs-485, de = on = gnd, sp = v l rs-485, de = on = sp = gnd 22.533.544.55 0 100 200 300 400 500 600 i cc and i l ( a) v l (v) no load v in = v l or gnd lb = v l on = dz/de = dy = gnd rs-232/rs-485 i cc sp = gnd sp = v l rs-232 i l rs-485 i l -40 0 50 85 temperature (c) -25 25 75 propagation delay (ns) 1400 1450 1500 1550 1600 1650 1700 t dlh t dhl r diff = 54 ? , c l = 100pf t dhl -40 0 50 85 temperature (c) skew (ns) -25 25 75 400 |t plhz - t phly | |t phlz - t plhy | |t dlh - t dhl | r diff = 54 ? , c l = 100pf 50 100 150 200 250 300 350 isl81334, isl41334
22 fn6202.1 december 20, 2005 figure 24. rs-485, driver propagation delay vs temperature (medium data rate, qfn only) figure 25. rs-485, driver skew vs temperature (medium data rate, qfn only) figure 26. rs-485, driver propagation delay vs temperature (fast data rate) figure 27. rs-485, driver skew vs temperature (fast data rate) figure 28. rs-485, driver and receiver waveforms, low to high (slow data rate, qfn only) figure 29. rs-485, driver and receiver waveforms, high to low (slow data rate, qfn only ) typical performance curves v cc = v l = 5v, t a = 25c; unless otherwise specified (continued) -40 0 50 85 temperature (c) -25 25 75 propagation delay (ns) 470 480 490 500 510 520 530 540 550 560 t dlh t dhl t dhl r diff = 54 ? , c l = 100pf -40 0 50 85 temperature (c) skew (ns) -25 25 75 0 20 40 60 80 100 120 r diff = 54 ? , c l = 100pf |t phlz - t plhy | |t plhz - t phly | |t dlh - t dhl | -40 0 50 85 temperature (c) -25 25 75 t dlh t dhl propagation delay (ns) 20 25 30 35 40 r diff = 54 ? , c l = 100pf -40 0 50 85 temperature (c) skew (ns) -25 25 75 0 0.5 1 1.5 2 2.5 r diff = 54 ? , c l = 100pf |t plhz - t phly | |t phlz - t plhy | |t dlh - t dhl | time (400ns/div) d y receiver output (v) driver output (v) 0 5 0 5 driver input (v) r diff = 60 ? , c l = 100pf r a 0 1 2 3 4 5 z y time (400ns/div) d y receiver output (v) driver output (v) 0 5 0 5 driver input (v) r diff = 60 ? , c l = 100pf r a 0 1 2 3 4 5 z y isl81334, isl41334
23 fn6202.1 december 20, 2005 figure 30. rs-485, driver and receiver waveforms, low to high (medium data rate, qfn only) figure 31. rs-485, driver and receiver waveforms, high to low (medium data rate, qfn only ) figure 32. rs-485, driver and receiver waveforms, low to high (fast data rate) figure 33. rs-485, driver and receiver waveforms, high to low (fast data rate ) figure 34. rs-232, transmitter output voltage vs load capacitance figure 35. rs-232, transmitter output voltage vs temperature typical performance curves v cc = v l = 5v, t a = 25c; unless otherwise specified (continued) time (200ns/div) d y receiver output (v) driver output (v) 0 5 0 5 driver input (v) r diff = 60 ? , c l = 100pf r a 0 1 2 3 4 5 z y time (200ns/div) d y receiver output (v) driver output (v) 0 5 0 5 driver input (v) r diff = 60 ? , c l = 100pf r a 0 1 2 3 4 5 z y time (10ns/div) d y receiver output (v) driver output (v) 0 5 0 5 driver input (v) r diff = 60 ? , c l = 100pf r a 0 1 2 3 4 5 z y time (10ns/div) d y receiver output (v) driver output (v) 0 5 0 5 driver input (v) r diff = 60 ? , c l = 100pf r a 0 1 2 3 4 5 z y -7.5 -5 -2.5 0 2.5 5 7.5 1000 2000 3000 4000 5000 0 load capacitance (pf) transmitter output voltage (v) 1 transmitter/port at 250kbps or 500kbps, v out + v out - other transmitters at 30kbps all t outs loaded with 3k ? to gnd 500kbps 500kbps 250kbps 250kbps rs-232 region of noncompliance -40 0 50 85 temperature (c) transmitter output voltage (v) -25 25 75 -7.5 -5 0 5 7.5 2.5 -2.5 v out + v out - outputs static all t outs loaded with 3k ? to gnd isl81334, isl41334
24 fn6202.1 december 20, 2005 figure 36. rs-232, transmitter short circuit current vs temperature figure 37. rs-232, transmitter and receiver waveforms at 250kbps figure 38. rs-232, transmitter and receiver waveforms at 500kbps figure 39. rs-232, receiver output +duty cycle vs data rate figure 40. rs-232, transmitter maximum data rate vs load capacitance figure 41. rs-232, transmitter output voltage vs data rate typical performance curves v cc = v l = 5v, t a = 25c; unless otherwise specified (continued) -40 0 50 85 temperature (c) transmitter output current (ma) -25 25 75 -40 -30 -20 -10 0 10 20 30 40 y or z = high y or z = low v out shorted to gnd 2 s/div. c l = 3500pf, 1 channel switching/port y/a 0 -5 0 5 0 5 5 ra dy 1 s/div. c l = 1000pf, 1 channel switching/port y/a 0 -5 0 5 0 5 5 ra dy 500 1000 1500 2000 48 50 52 54 56 58 60 data rate (kbps) receiver + duty cycle (%) full temp range sr in = 15v/ s sr in = 100v/ s 50 v in = 5v 100 1000 2000 3000 4000 5000 100 200 300 400 500 600 700 800 900 1000 1100 load capacitance (pf) data rate (kbps) 2 transmitters at 25c 2 transmitters at 85c 1 transmitter at 25c v out 4v all t outs loaded with 5k ? to gnd 1 transmitter at 85c 0 100 200 300 400 500 600 700 800 -7.5 -5 0 5 7.5 2.5 -2.5 data rate (kbps) transmitter output voltage (v) 25 c 85 c 25 c 85 c v out + v out - 1 transmitter switching on each port all t outs loaded with 5k ? to gnd, c l = 1000pf rs-232 region of noncompliance isl81334, isl41334
25 fn6202.1 december 20, 2005 die characteristics substrate potential (powered up): gnd transistor count: 4838 process: bicmos figure 42. rs-232, transmitter skew vs data rate figure 43. rs-485, transmitter jitter vs data rate with 2000? cat 5 cable figure 44. rs-485, transmitter jitter vs data rate with 1000? cat 5 cable figure 45. rs-485, transmitter jitter vs data rate with 350? cat 5 cable typical performance curves v cc = v l = 5v, t a = 25c; unless otherwise specified (continued) 50 150 250 350 450 550 650 750 150 200 250 300 350 400 450 data rate (kbps) skew (ns) 25c 85c all t outs loaded with 3k ? to gnd, c l = 1000pf 1 transmitter switching on each port data rate (kbps) jitter (%) 32 100 200 300 400 500 600 700 800 900 1000 0.1 1 10 100 double term?ed with 121 ? slow med fast data rate (kbps) jitter (%) 32 100 200 300 400 500 600 700 800 900 1000 0.1 1 10 100 double term?ed with 121 ? slow med fast data rate (kbps) jitter (%) 32 100 200 300 400 500 600 700 800 900 1000 0.1 1 10 100 double term?ed with 121 ? slow med fast isl81334, isl41334
26 fn6202.1 december 20, 2005 small outline plast ic packages (soic) notes: 1. symbols are defined in the ?mo series symbol list? in section 2.2 of publication number 95. 2. dimensioning and tolerancing per ansi y14.5m - 1982. 3. dimension ?d? does not include mo ld flash, protrusions or gate burrs. mold flash, protrusion and gate burrs shall not exceed 0.15mm (0.006 inch) per side. 4. dimension ?e? does not include in terlead flash or protrusions. in- terlead flash and protrusions shall not exceed 0.25mm (0.010 inch) per side. 5. the chamfer on the body is optional . if it is not present, a visual index feature must be located within the crosshatched area. 6. ?l? is the length of terminal for soldering to a substrate. 7. ?n? is the number of terminal positions. 8. terminal numbers are shown for reference only. 9. the lead width ?b?, as measured 0.36mm (0.014 inch) or greater above the seating plane, shall not exceed a maximum value of 0.61mm (0.024 inch) 10. controlling dimension: millimeter. converted inch dimen- sions are not necessarily exact. index area e d n 123 -b- 0.25(0.010) c a m bs e -a- l b m -c- a1 a seating plane 0.10(0.004) h x 45 o c h 0.25(0.010) b m m m28.3 (jedec ms-013-ae issue c ) 28 lead wide body small outline plastic package symbol inches millimeters notes min max min max a 0.0926 0.1043 2.35 2.65 - a1 0.0040 0.0118 0.10 0.30 - b 0.013 0.0200 0.33 0.51 9 c 0.0091 0.0125 0.23 0.32 - d 0.6969 0.7125 17.70 18.10 3 e 0.2914 0.2992 7.40 7.60 4 e 0.05 bsc 1.27 bsc - h 0.394 0.419 10.00 10.65 - h 0.01 0.029 0.25 0.75 5 l 0.016 0.050 0.40 1.27 6 n28 287 0 o 8 o 0 o 8 o - rev. 0 12/93 isl81334, isl41334
27 fn6202.1 december 20, 2005 isl81334, isl41334 shrink small outline plastic packages (ssop) notes: 1. symbols are defined in the ?mo seri es symbol list? in section 2.2 of publication number 95. 2. dimensioning and tolerancing per ansi y14.5m - 1982. 3. dimension ?d? does not include mo ld flash, protrusions or gate burrs. mold flash, protrusion and gate burrs shall not exceed 0.20mm (0.0078 inch) per side. 4. dimension ?e? does not include interlead flash or protrusions. interlead flash and protrusions shall not exceed 0.20mm (0.0078 inch) per side. 5. the chamfer on the body is optional . if it is not present, a visual index feature must be located within the crosshatched area. 6. ?l? is the length of terminal for soldering to a substrate. 7. ?n? is the number of terminal positions. 8. terminal numbers are shown for reference only. 9. dimension ?b? does not include dambar protrusion. allowable dambar protrusion shall be 0.13mm (0.005 inch) total in excess of ?b? dimension at maximum material condition. 10. controlling dimension: millimete r. converted inch dimensions are not necessarily exact. index area e d n 123 -b- 0.25(0.010) c a m bs e -a- l b m -c- a1 a seating plane 0.10(0.004) c h 0.25(0.010) b m m 0.25 0.010 gauge plane a2 m28.209 (jedec mo-150-ah issue b) 28 lead shrink small outline plastic package symbol inches millimeters notes min max min max a - 0.078 - 2.00 - a1 0.002 - 0.05 - - a2 0.065 0.072 1.65 1.85 - b 0.009 0.014 0.22 0.38 9 c 0.004 0.009 0.09 0.25 - d 0.390 0.413 9.90 10.50 3 e 0.197 0.220 5.00 5.60 4 e 0.026 bsc 0.65 bsc - h 0.292 0.322 7.40 8.20 - l 0.022 0.037 0.55 0.95 6 n28 287 0 8 0 8 - rev. 2 6/05
28 all intersil u.s. products are manufactured, asse mbled and tested utilizing iso9000 quality systems. intersil corporation?s quality certifications ca n be viewed at www.intersil.com/design/quality intersil products are sold by description only. intersil corpor ation 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 furnishe d by intersil is believed to be accurate and reliable. however, no responsibility is assumed by intersil or its subsidiaries for its use; nor for any infringements of paten ts 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 intersil or its subsidiari es. for information regarding intersil corporation and its products, see www.intersil.com fn6202.1 december 20, 2005 quad flat no-lead plastic package (qfn) micro lead frame pl astic package (mlfp) l40.6x6 40 lead quad flat no-lead plastic package (compliant to jedec mo-220vjjd-2 issue c) symbol millimeters notes min nominal max a 0.80 0.90 1.00 - a1 - - 0.05 - a2 - - 1.00 9 a3 0.20 ref 9 b 0.18 0.23 0.30 5, 8 d 6.00 bsc - d1 5.75 bsc 9 d2 3.95 4.10 4.25 7, 8 e 6.00 bsc - e1 5.75 bsc 9 e2 3.95 4.10 4.25 7, 8 e 0.50 bsc - k0.25 - - - l 0.30 0.40 0.50 8 l1 - - 0.15 10 n402 nd 10 3 ne 10 3 p- -0.609 --129 rev. 1 10/02 notes: 1. dimensioning and tolerancing conform to asme y14.5-1994. 2. n is the number of terminals. 3. nd and ne refer to the number of terminals on each d and e. 4. all dimensions are in millimeters. angles are in degrees. 5. dimension b applies to the meta llized terminal and is measured between 0.15mm and 0.30mm from the terminal tip. 6. the configuration of the pin #1 identifier is optional, but must be located within the zone indicated. the pin #1 identifier may be either a mold or mark feature. 7. dimensions d2 and e2 are fo r the exposed pads which provide improved electrical and thermal performance. 8. nominal dimensions are provided to assist with pcb land pattern design efforts, see intersil technical brief tb389. 9. features and dimensions a2, a3, d1, e1, p & are present when anvil singulation method is used and not present for saw singulation. 10. depending on the method of lead termination at the edge of the package, a maximum 0.15mm pull back (l1) maybe present. l minus l1 to be equal to or greater than 0.3mm. isl81334, isl41334

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