features four independent drivers and receivers driver slew rate controlled by a single resistor fast driver transition times down to 1.5 s and receiver transition times of 20 ns typ internal thermal-overload protection rs-423-b inputs and outputs designed to withstand 25 v esd protection exceeds 2000 v per mil-std-833c method 3015 linbicmos ? process technology description the sn75lbc784 performs as four independent rs-423-b driver/receiver pairs designed to interface data terminal equipment (dte) with data circuit-terminating equipment (dce) at rates up to 120 kbps and distances to 1.2 km. the sn75lbc784 provides an upgrade to the rs-232 serial interface and can be backwards-compatible with existing serial ports while offering the higher performance required by new faster peripherals, such as v.34 (v.fast) modems. the rs-232 standard, and subsequent revisions, only supports data rates up to 20 kbps over about 15 meters of cable. for rs-423-b the data rate is increased to 120 kbps and transmission distance to 1.2 km by reducing the maximum output signal swing, increasing the driver output current, and reducing the receiver input voltage thresholds. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 28 27 26 25 24 23 22 21 20 19 18 17 16 15 3a 3z bias 4a 4z bias v ss gnd 4b 4y 3b 3y 3c 4c bias 2z 2a bias 1z 1a r ws v dd 1y 1b 2y 2b 2c 1c dw package (top view) inputs outputs l h l h function table ab l l h h h h l l h h l l zy h l h l h = high level, l = low level, x = irrelevant, z = high impedance (off) ? = indeterminate l h l h l l h h l l h h ? ? ? ? h l h l c the receivers consist of differential comparators with hysteres is and resistive attenuation on the inputs. the resistive attenu ation improves the input common-mode range and also provides additional protection from esd and over-voltage stress. the differential and common-mode input impedances are sufficiently high to meet rs -423-b. when a differential voltage input of 500 mv is applied across the entire common-mode range (see figure 5), the receiver characteristics and bias voltage allow the receiver to remain in its intended binary state. the drivers meet all rs-423-b specifications with built-in current limits and therma l overload protection. slew-rate controllin g circuitry is included in the design, which is adjusted to suit the application by means of an external resistor (r ws) . the slew rate controlling circuitry also has a default mode?if the r ws pin is shorted to 5 v externally, the transistion time defaults to approximately 1.5 ms. the bias input, when shorted to 5 v externally, provides the internal node voltages. the receiver is compatible to rs-2 32 with the use of external input resistors to meet the rs-232 input resist ance specification of 3 k ? to 7 k ? . the sn75lbc784 is characterized for oper ation over the temperature range of 0 c to +70 c. www.ti.com sn75lbc784 slls187b ? november 1994 ? revised june 2007 quadruple rs-423-b driver/receiver www.ti.com copyright ? 1994?2007, t exas instruments incorporated please be aware that an important notice concerning availability, standard warranty, and use in critical applications of t exas instruments semiconductor products and disclaimers thereto appears at the end of this data sheet. linbicmos is a trademark of texas instruments incorporated. all other trademarks are the property of their respective owners.
slls187b ? november 1994 ? revised june 2007 www.ti.com 2 logic diagram (positive logic) _ + 12 1 2 11 13 3y 3b 3c 3a 3z 10 4 4y 4a 20 23 1y 1a 18 26 2y 2a _ + 5 9 14 4b 4c 4z _ + 24 19 15 1b 1c 1z _ + 27 17 16 2b 2c 2z absolute maximum ratings over operating free-air temperature range (unless otherwise noted) ? positive supply voltage, v dd (1) 14 v . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . negative supply voltage, v ss ?14 v . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . bias voltage, v bias 5.75 v . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . receiver input voltage range ?30 v to 30 v . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . driver input voltage range ?0.5 v to 5.75 v . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . driver output voltage range (supplies at 0 v) ?30 v to 30 v . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . driver output voltage range (supplies at 12 v) ?25 v to 25 v . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . continuous power dissipation see dissipation rating table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . operating free-air temperature range, t a 0 c to +70 c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . storage temperature range ?65 c to +150 c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . case temperature for 10 seconds +260 c . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ? stresses beyond those listed under absolute maximum ratings may cause permanent damage to the device. these are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated under recommended operating cond itions is not implied. exposure to absolute-maximum-rated conditions for extended periods may affect device reliability. (1) all voltages are with respect to network ground terminal. dissipation rating table package t a +25 c power rating derating factor ? above t a = +25 c t a = +70 c power rating dw 1348 mw 10.8 mw/ c 862 mw ? derating factors are the inverse of the junction-to-ambient thermal resistance when board-mounted with no air flow. recommended operating conditions min nom max unit supply voltage, v dd 10.8 12 13.2 v supply voltage, v ss ?10.8 ?12 ?13.2 v bias voltage, v bias 2 5 5.5 v high-level input voltage, v ih driver 2 v low-level input voltage, v il driver 0.8 v high-level output current, i oh receiver ?4 ma low-level output current, i ol receiver 4 ma rws slew rate control resistor 20 82 820 k ? operating free-air temperature, t a 0 +70 c
slls187b ? november 1994 ? revised june 2007 www.ti.com 3 driver section electrical characteristics over recommended ra nges of supply voltage and operating free-air temperature, v dd = 10.8 v to 13.2 v, v ss = ?10.8 v to ?13.2 v, t a = 0 c to +70 c (unless otherwise noted). parameter test conditions min typ max unit v oh high-level output voltage open circuit or r l = 450 ? 4 5.5 6 v v ol low-level output voltage open circuit or r l = 450 ? ?6 ?5.5 ?4 v i ih high-level input current v i = 2.4 v to 5.5 v 100 a i il low-level input current v i = 0 v to 0.8 v ?100 a i o output leakage current v dd = v ss = 0, v o = 6 v ?100 100 a i os(h) high-level short circuit output current v i = 5 v, v o = 0 15 45 ma i os(l) low-level short circuit output current v i = 0, v o = 0 ?45 ?15 ma i dd supply current no load 10 12 ma i dd supply current r l = 450 ? 60 70 ma i ss supply current no load ?10 ?12 ma i ss supply current r l = 450 ? ?60 ?70 ma i bias bias current 400 a switching characteristics over recommended ranges of supply voltage and operating free-air temperature, v dd = 10.8 v to 13.2 v, v ss = ?10.8 v to ?13.2 v, t a = 0 c to +70 c (unless otherwise noted). parameter test conditions min typ max unit r ws = 0 k ? 1.5 transition time, low-to-high level r ws = 20 k ? 1.5 2.1 2.7 s t tlh transition time, low-to-high level (see figure 1) r ws = 82 k ? 5 8 11 s t tlh (see figure 1) r ws = 820 k ? 80 r l = 450 ? , c l = 50 pf, r ws = 0 k ? 1.5 transition time, high-to-low level r l = 450 ? , v ws = 5 v c l = 50 pf, r ws = 20 k ? 1.5 2.1 2.7 s t thl transition time, high-to-low level (see figure 1) v ws = 5 v r ws = 82 k ? 5 8 11 s t thl (see figure 1) r ws = 820 k ? 80 sr output slew rate rws = 20 k ? 15 v/ s t sk output skew (see figure 4) |t phl ? t plh | r ws = 82 k ? 1 s
slls187b ? november 1994 ? revised june 2007 www.ti.com 4 receiver section electrical characteristics over recommended ra nges of supply voltage and operating free-air temperature, v dd = 10.8 v to 13.2 v, v ss = ?10.8 v to ?13.2 v, t a = 0 c to +70 c (unless otherwise noted) parameter test conditions min typ max unit v it+ positive input threshold voltage 200 mv v it+ positive input threshold voltage with 500 ? series resistor 400 mv v it? negative input threshold voltage ?200 mv v it? negative input threshold voltage with 500 ? series resistor ?400 mv i i input current v i = 10 v other input to gnd 1.3 3.25 ma i i input current v i = ? 10 v other input to gnd ?3.25 ?1.3 ma v hys hysteresis (v it + ? v it ? ) 20 40 150 mv v oh high-level output voltage (1) i o = ?20 a 3.5 5 v v oh high-level output voltage (1) i o = ? 4 ma 2.4 5 v v ol low-level output voltage i o = 20 a to 4 ma 0.4 v i rx rx short circuit current 50 ma v id differential input voltage receiver inputs open circuit 1.6 2.1 2.6 v v ofs fail safe output voltage see note 2 3.5 v (1) device has an internal rx supply regulator. maximum rx logic output voltage under no load is thus defined by an internal voltag e value. this is nominally set to 4.5 v with a tolerance of 5%. (2) one input at ground, other input open circuit, i o = ?20 a, or both open circuit. switching characteristics over recommended ra nges of supply voltage and operating free-air temperature (unless otherwise noted) test conditions: v dd = 10.8 v to 13.2 v, v ss = ?10.8 v to ?13.2 v, t a = 0 c to +70 c (unless otherwise noted) parameter test conditions min nom max unit t plh propagation delay time low-to-high (see figure 2) 0.15 1 s t phl propagation delay time high-to-low (see figure 2) c l = 50 pf 0.15 1 s t thl transition time high-to-low (see figure 3) c l = 50 pf 20 200 ns t tlh transition time low-to-high (see figure 3) 20 200 ns
slls187b ? november 1994 ? revised june 2007 www.ti.com 5 parameter measurement information v dd v ss r l c l 51 ? input r ws output 5 v t thl t tlh 90% 90% 10% 10% v oh v ol output input (see note a and b) gnd gnd 3 v 0 v figure 1. driver transition times v dd v ss c l input output t phl t plh output input (see note a and c) gnd gnd 50% 50% 50% 50% 51 ? 0.5 v ? 0.5 v + ? figure 2. receiver propagation delay times t thl t tlh 90% 90% 10% 10% v oh v ol output input (see note a and c) v dd v ss c l input output gnd gnd + ? 0.5 v ?0.5 v 51 ? figure 3. receiver transition times notes:a. c l includes probe and jig capacitance. b. the input pulse is supplied by a generator having the following characteristics: t r 10 ns, t f < 10 ns, z o = 50 ? , prr 5 khz, duty cycle 50%, v max = 3 v, v min = 0 v. c. the input pulse is supplied by a generator having the following characteristics: t r 10 ns, t f < 10 ns, z o = 50 ? , prr 5 khz, duty cycle 50%, v max = 0.5 v, v min = ? 0.5 v.
slls187b ? november 1994 ? revised june 2007 www.ti.com 6 parameter measurement information, continued 50% 50% 50% 50% t plh t phl input a output y figure 4. skew definition times v cm 250 mw 250 mw 500 ? 500 ? v cm = ? 7 v to 7 v figure 5. receiver input balance test
revision history date rev page section description 6/07 b front page ? updated front page. 6/07 b 2 ? corrected pin references in positive logic diagram (receiver 1, receiver 2). note : page numbers for previous revisions may differ from page numbers in the current version.
packaging information orderable device status (1) package type package drawing pins package qty eco plan (2) lead/ball finish msl peak temp (3) SN75LBC784DW obsolete soic dw 28 tbd call ti call ti SN75LBC784DWg4 obsolete soic dw 28 tbd call ti call ti SN75LBC784DWr obsolete soic dw 28 tbd call ti call ti SN75LBC784DWrg4 obsolete soic dw 28 tbd call ti call ti (1) the marketing status values are defined as follows: active: product device recommended for new designs. lifebuy: ti has announced that the device will be discontinued, and a lifetime-buy period is in effect. nrnd: not recommended for new designs. device is in production to support existing customers, but ti does not recommend using this part in a new design. preview: device has been announced but is not in production. samples may or may not be available. obsolete: ti has discontinued the production of the device. (2) eco plan - the planned eco-friendly classification: pb-free (rohs), pb-free (rohs exempt), or green (rohs & no sb/br) - please check http://www.ti.com/productcontent for the latest availability information and additional product content details. tbd: the pb-free/green conversion plan has not been defined. pb-free (rohs): ti's terms "lead-free" or "pb-free" mean semiconductor products that are compatible with the current rohs requirements for all 6 substances, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. where designed to be soldered at high temperatures, ti pb-free products are suitable for use in specified lead-free processes. pb-free (rohs exempt): this component has a rohs exemption for either 1) lead-based flip-chip solder bumps used between the die and package, or 2) lead-based die adhesive used between the die and leadframe. the component is otherwise considered pb-free (rohs compatible) as defined above. green (rohs & no sb/br): ti defines "green" to mean pb-free (rohs compatible), and free of bromine (br) and antimony (sb) based flame retardants (br or sb do not exceed 0.1% by weight in homogeneous material) (3) msl, peak temp. -- the moisture sensitivity level rating according to the jedec industry standard classifications, and peak solder temperature. important information and disclaimer: the information provided on this page represents ti's knowledge and belief as of the date that it is provided. ti bases its knowledge and belief on information provided by third parties, and makes no representation or warranty as to the accuracy of such information. efforts are underway to better integrate information from third parties. ti has taken and continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals. ti and ti suppliers consider certain information to be proprietary, and thus cas numbers and other limited information may not be available for release. in no event shall ti's liability arising out of such information exceed the total purchase price of the ti part(s) at issue in this document sold by ti to customer on an annual basis. package option addendum www.ti.com 6-apr-2009 addendum-page 1
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