View LTC1346A-15_8379533.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

1 ltc1346a 1346afa 10mbps dce/dte v .35 transceiver single chip provides complete differential signal interface for v.35 port drivers and receivers will withstand repeated 10kv esd pulses operates from 5v supplies 10mbaud transmission rate meets ccitt v.35 specification shutdown mode reduces i cc to below 1 a selectable transmitter and receiver configurations independent driver/receiver enables transmitter maintains high impedance when disabled, shut down or with power off transmitters are short-circuit protected the ltc 1346a is a single chip transceiver that provides the differential clock and data signals for a v.35 interface from 5v supplies. combined with an external resistor termination network and an lt 1134a rs232 transceiver for the control signals, the ltc1346a forms a complete low power dte or dce v.35 interface port. the ltc1346a features three current output differential transmitters and three differential receivers. the transceiver can be configured for dte or dce operation or shutdown using three select pins. in the shutdown mode, the supply current is reduced to below 1 a. the ltc1346a transceiver operates up to 10mbaud. all transmitters feature short-circuit protection. both the transmitter outputs and the receiver outputs can be forced into a high impedance state. the transmitter outputs and receiver inputs feature 10kv esd protection. modems telecommunications data routers v cc1 5v 2 1 4 1 2 24 23 12 dte dce 10 11 16 15 0.1 f ltc1346a ltc1346a bi 627t500/1250 bi 627t500/1250 bi technologies 627t500/1250 (soic) v cc2 5v 0.1 f 2 t txd (103) scte (113) txc (114) rxc (115) rxd (104) gnd (102) t 5 3 4 22 21 10 11 9 14 13 dx rx t t 9 14 13 18 17 1 4 2 24 23 t t 10 12 11 16 15 12 7 8 3 5 4 22 21 t t 7 8 11 8 7 10 9 14 13 3 5 6 8 7 v cc2 v cc1 6 20 19 3 t t rx rx rx 12 ltc1346 ?ta01 dx dx dx 50 = 125 t 50 + v ee2 ?v 0.1 f 1 + + v ee1 ?v 0.1 f + dx rx clock and data signals for v.35 interface features descriptio u applicatio s u typical applicatio u , ltc and lt are registered trademarks of linear technology corporation.
2 ltc1346a 1346afa a u g w a w u w a r b s o lu t exi t i s wu u package / o rder i f or atio t jmax = 150 c, ja = 85 c/w (note 1) supply voltage v cc .................................................................... 6.5v v ee ................................................................... 6.5v input voltage transmitters ........................... 0.3v to (v cc + 0.3v) receivers ............................................... 18v to 18v s0, s1, s2 ............................... 0.3v to (v cc + 0.3v) output voltage transmitters .......................................... 18v to 18v receivers ................................ 0.3v to (v cc + 0.3v) short-circuit duration transmitter output ..................................... indefinite receiver output .......................................... indefinite operating temperature range ltc1346ac ............................................ 0 c to 70 c storage temperature range ................ 65 c to 150 c lead temperature (soldering, 10 sec)................. 300 c 1 2 3 4 5 6 7 8 9 10 11 12 24 23 22 21 20 19 18 17 16 15 14 13 v ee v cc gnd t1 t2 t3 s1 s2 r3 r2 r1 s0 y1 z1 y2 z2 y3 z3 a3 b3 a2 b2 a1 b1 sw package 24-lead plastic so wide top view order part number symbol parameter conditions min typ max units v od transmitter differential output voltage 4v v os 4v (figure 1) 0.44 0.55 0.66 v v oc transmitter common mode output voltage v os = 0v (figure 1) 0.6 0 0.6 v i oh transmitter output high current v y, z = 0v 12.6 11 9.4 ma i ol transmitter output low current v y, z = 0v 9.4 11 12.6 ma i oz transmitter output leakage current 5v v y, z 5v, s1 = s2 = 0v 1 20 a 100 a r o transmitter output impedance 2v v y, z 2v 100 k ? v th differential receiver input threshold voltage 7v (v a + v b )/2 12v 25 200 mv ? v th receiver input hysterisis 7v (v a + v b )/2 12v 50 mv i in receiver input current (a, b) 7v v a, b 12v 0.7 ma r in receiver input impedance 7v v a, b 12v 17.5 30 k ? v oh receiver output high voltage i o = 4ma, v a, b = 0.2v 3 4.5 v v ol receiver output low voltage i o = 4ma, v a, b = 0.2v 0.2 0.4 v i osr receiver output short-circuit current 0v v o v cc 74085 ma i ozr receiver three-state output current s0 = v cc , 0v v o v cc 10 a v ih logic input high voltage t, s0, s1, s2 2v v il logic input low voltage t, s0, s1, s2 0.8 v i in logic input current t, s0, s1, s2 10 a dc electrical characteristics ltc1346acsw the denotes specifications which apply over the full operating temperature range. v cc = 5v 5%, v ee = 5v 5% (note 2) consult ltc marketing for parts specified with wider operating temperature ranges.
3 ltc1346a 1346afa symbol parameter conditions min typ max units i cc v cc supply current v os = 0v, s0 = low, s1 = s2 = high (figure 1) 40 50 ma no load, s0 = low, s1 = s2 = high 6 9 ma shutdown, s0 = v cc , s1 = s2 = 0v 0.1 100 a i ee v ee supply current v os = 0v, s0 = low, s1 = s2 = high (figure 1) ?0 50 ma no load, s0 = low, s1 = s2 = high ? ? ma shutdown, s0 = v cc , s1 = s2 = 0v 0.1 100 a t r , t f transmitter rise or fall time v os = 0v (figures 1, 3) 740 ns t plh transmitter input to output v os = 0v (figures 1, 3) 25 70 ns t phl transmitter input to output v os = 0v (figures 1, 3) 30 70 ns t skew transmitter output to output v os = 0v (figures 1, 3) 5 ns t plh receiver input to output v os = 0v (figures 1, 4) 50 100 ns t phl receiver input to output v os = 0v (figures 1, 4) 55 100 ns t skew differential receiver skew, ? t plh ?t phl ? v os = 0v (figures 1, 4) 5 ns t zl receiver enable to output low (active mode) c l = 15pf, sw1 closed (figures 2, 5) 40 70 ns receiver enable to output low c l = 15pf, sw1 closed (figures 2, 5) 2 s (from shutdown, note 3) t zh receiver enable to output high (active mode) c l = 15pf, sw2 closed (figures 2, 5) 35 70 ns receiver enable to output high c l = 15pf, sw2 closed (figures 2, 5) 2 s (from shutdown, note 3) t lz receiver disable from low c l = 15pf, sw1 closed (figures 2, 5) 30 70 ns t hz receiver disable from high c l = 15pf, sw2 closed (figures 2, 5) 35 70 ns ac electrical characteristics note 1: the absolute maximum ratings are those values beyond which the life of a device may be impaired. note 2: all currents into device pins are positive; all currents out of device pins are termed negative. all voltages are referenced to device ground unless otherwise specified. note 3: receiver enable to output valid high or low from shutdown is typically 2 s. typical perfor a ce characteristics uw temperature (?c) ?0 ? output current ? (ma) 25 1346a g01 11 10 ?5 0 50 9 13 12 75 100 125 v cc = 5v v ee = 5v transmitter output current vs temperature output voltage (v) 2.0 ? output current ? (ma) 11 12 2.0 1346a g02 10 9 ?.0 0 1.0 13 ?.5 0.5 0.5 1.5 t a = 25 c v cc = 5v v ee = 5v transmitter output current vs output voltage transmitter output skew vs temperature temperature (?c) ?0 time (ns) 25 1346a g03 10 5 ?5 0 50 0 20 15 75 100 125 v cc = 5v v ee = 5v the denotes specifications which apply over the full operating temperature range. v cc = 5v 5%, v ee = 5v 5% (note 2)
4 ltc1346a 1346afa typical perfor a ce characteristics uw b1 (pin 13): receiver 1 inverting input a1 (pin 14): receiver 1 noninverting input b2 (pin 15): receiver 2 inverting input a2 (pin 16): receiver 2 noninverting input b3 (pin 17): receiver 3 inverting input a3 (pin 18): receiver 3 noninverting input z3 (pin 19): transmitter 3 inverting output y3 (pin 20): transmitter 3 noninverting output z2 (pin 21): transmitter 2 inverting output y2 (pin 22): transmitter 2 noninverting output z1 (pin 23): transmitter 1 inverting output y1 (pin 24): transmitter 1 noninverting output v ee (pin 1): negative supply, 4.75v v ee 5.25v v cc (pin 2): positive supply, 4.75v v cc 5.25v gnd (pin 3) : ground t1 (pin 4): transmitter 1 input, ttl compatible t2 (pin 5): transmitter 2 input, ttl compatible t3 (pin 6): transmitter 3 input, ttl compatible s1 (pin 7): select input 1, ttl compatible s2 (pin 8): select input 2, ttl compatible r3 (pin 9): receiver 3 output, ttl compatible r2 (pin 10): receiver 2 output, ttl compatible r1 (pin 11): receiver 1 output, ttl compatible s0 (pin 12): select input 0, ttl compatible pi n fu n ctio n s uuu input 0.2v/div input 5v/div output 0.2v/div 1346a g07 1346a g08 1346a g09 input a? 1v/div receiver enable from shutdown input s0 5v/div output 5v/div output 5v/div receiver output waveforms transmitter output waveforms temperature (?c) ?0 current (ma) current (ma) 25 1346a g06 ?5 ?0 ?5 0 50 ?5 ?5 ?0 ?.0 ?.5 ?.0 ?.0 ?.5 75 100 125 loaded no load v cc = 5v v ee = 5v i ee supply current vs temperature temperature (?c) ?0 current (ma) current (ma) 25 1346a g05 35 30 ?5 0 50 25 45 40 6.5 6.0 5.5 7.5 7.0 75 100 125 loaded no load v cc = 5v v ee = 5v temperature (?c) ?0 time (ns) 25 1346a g04 10 5 ?5 0 50 0 20 15 75 100 125 v cc = 5v v ee = 5v receiver t plh ?t phl vs temperature i cc supply current vs temperature
5 ltc1346a 1346afa fu ctio tables u u transmitter and receiver configuration s0 s1 s2 dx on rx on description 000 1, 2, 3 all rx on, all dx off 10 0 ? ll off, shutdown 01 0 1, 2, 3 1, 2 dce mode 11 0 1, 2, 3 dce mode, all rx off 001 1, 2 1, 2, 3 dte mode 10 1 1, 2 dte mode, all rx off 011 1, 2, 3 1, 2, 3 all on 111 1, 2, 3 all dx on, all rx off transmitter inputs outputs configuration s0 s1 s2 t y1 and y2 z1 and z2 y3 z3 all off 0 0 0 x z z z z shutdown 1 0 0 x z z z z dce or all on x 1 x 0 0 1 0 1 dce or all on x 1 x 1 1 0 1 0 dte x 0 1 0 01zz dte x 0 1 1 10zz receiver inputs outputs configuration s0 s1 s2 a ?b r1 and r2 r3 all rx on 0 0 0 0.2v 0 0 all rx on 0 0 0 0.2v 1 1 shutdown 1 0 0 x z z dce 0 1 0 0.2v 0 z dce 0 1 0 0.2v 1 z disabled 1 1 0 x z z dte or all on 0 x 1 0.2v 0 0 dte or all on 0 x 1 0.2v 1 1 disabled 1 x 1 x z z test circuits c l 1k ltc1346a ?f02 sw1 sw2 v cc receiver output figure 2. receiver output enable and disable timing test load 15pf s0 r 50 ? 125 ? y z z y t 125 ? 50 ? 50 ? ltc1346a ?f01 50 ? a b v od v os v oc = (v y + v z )/2 figure 1. v.35 transmitter/receiver test circuit
6 ltc1346a 1346afa switchi g ti e wavefor s uw w figure 5. receiver enable and disable times 1.5v 3v 0v s0 f = 1mhz: t r 10ns: t f 10ns 1.5v r v ol 5v t zl t lz 0.5v output normally low 0v ltc1346a ?f05 1.5v 1.5v t zh v oh output normally high t hz 0.5v r 1.5v 3v 0v t y ?z f = 1mhz: t r 10ns: t f 10ns 1.5v ? o v o t skew 1/2 v o ltc1346a ?f03 t plh t r 90% 50% 10% t phl t f 90% 50% 10% v o t skew v diff = v(y) ?v(z) z y figure 4. v.35 receiver propagation delays v od /2 a ?b r v ol v oh ltc1346a ?f04 t plh t phl ? od /2 1.5v 1.5v 0v 0v input output f = 1mhz: t r 10ns: t f 10ns figure 3. v.35 transmitter propagation delays
7 ltc1346a 1346afa applicatio n s i n for m a tio n wu u u review of ccitt recommendation v.35 electrical specifications v.35 is a ccitt recommendation for synchronous data transmission via modems. appendix 2 of the recommen- dation describes the electrical specifications which are summarized below: 1. the interface cable is a balanced twisted pair with 80 ? to 120 ? impedance. 2. the transmitter? source impedance is between 50 ? and 150 ? . 3. the transmitter? resistance between shorted termi- nals and ground is 150 ? 15 ? . 4. when terminated by a 100 ? resistive load, the termi- nal-to-terminal voltage should be 0.55v 20%. 5. the transmitter? rise time should be less than 1% of the signal pulse or 40ns, whichever is greater. 6. the common mode voltage at the transmitter output should not exceed 0.6v. 7. the receiver impedance is 100 ? 10 ? . 8. the receiver impedance to ground is 150 ? 15 ? . 9. the transmitter or receiver should not be damaged by connection to earth ground, short-circuiting or cross connection to other lines. 10. no data errors should occur with 2v common mode change at either the transmitter/receiver or 4v ground potential difference between transmit- ter and receiver. cable termination each end of the cable connected to an ltc1346a must be terminated by an external y- or ? -resistor network for proper operation. the y-termination has two series con- nected 50 ? resistors and a 125 ? resistor connected between ground and the center tap of the two 50 ? resistors as shown in figure 6. the alternative ? -termination has a 120 ? resistor across the twisted wires and two 300 ? resistors between each wire and ground. standard 1/8w, 5% surface mount resistors can be used for the termination network. to maintain the proper differential output swing, the resistor tolerance must be 5% or better. a termination network that combines all the resistors into an so-14 package is available from: bi technologies (formerly beckman industrial) resistor networks 4200 bonita place fullerton, ca 92635 http://www.bitechnologies.com phone: (714) 447-2357 fax: (714) 447-2500 part #: bi technologies 627t500/1250 (soic) 899-5-500/1250 (dip) figure 6. y- and ? -termination networks 50 ? 50 ? 125 ? y ltc1346a ?f06 300 ? 300 ? 120 ? ?
8 ltc1346a 1346afa applicatio n s i n for m a tio n wu u u theory of operation the transmitter outputs consist of complementary switched-current sources as shown in figure 7. with a logic zero at the transmitter input, the inverting output z sources 11ma and the noninverting output y sinks 11ma. the differential transmitter output voltage is then set by the termination resistors. with two differential 50 ? resistors at each end of the cable, the voltage is set to (50 ? )(11ma) = 0.55v. with a logic 1 at the transmitter input, output z sinks 11ma and y sources 11ma. the common mode voltage of y and z is 0v when both current sources are matched and there is no ground potential difference between the cable terminations. the transmitter current sources have a common mode range of 2v, which allows for a ground difference between cable terminations of 4v. each receiver input has a 30k resistance to ground and requires external termination to meet the v.35 input imped- ance specification. the receivers have an input hysteresis of 50mv to improve noise immunity. three select pins, s0, s1 and s2, configure the chip as described in function tables. when the transmitters and figure 7. simplified transmitter schematic 11ma 11ma ltc1346a ?f07 y z t 50 ? 125 ? 50 ? v cc v ee chip boundary receivers are off, all outputs are forced into high imped- ance. the s0 pin can be used as receiver output enable. in shutdown mode, i cc drops to 1 a with all transmitters and receivers off. when the ltc1346a is enabled from shutdown the transmitters and receivers require 2 s to stabilize. complete v.35 port figure 8 shows the schematic of a complete surface mounted, 5v dte and dce v.35 port using only three ics and six capacitors per port. the ltc1346a is used to transmit the clock and data signals and the lt1134a to transmit the control signals. if test signals 140, 141 and 142 are not used, the transmitter inputs should be tied to v cc . rs422/rs485 applications the receivers on the ltc1346a can be used for rs422 and rs485 applications. using the test circuit in figure 9, the ltc1346a receivers are able to successfully extract the data stream from the common mode voltage, meeting rs422 and rs485 requirements as shown in figures 10 and 11.
9 ltc1346a 1346afa applicatio n s i n for m a tio n wu u u figure 8. complete single 5v v.35 interface dte dce v cc1 5v v ee1 ?v 0.1 f 1 2 4 1 2 24 23 12 p s u w y x v t r 10 11 16 15 0.1 f dx ltc1346a ltc1346a bi 627t500/ 1250 (soic) v cc2 5v v ee2 ?v 0.1 f 2 1 0.1 f rx t txd (103) scte (113) txc (114) rxc (115) rxd (104) gnd (102) cable shield 5 3 aa p s u w y x v t r bb aa aa 4 22 21 10 11 9 14 13 dx rx t 9 14 13 18 17 1 4 2 24 23 t 10 12 11 16 15 8 7 8 12 3 5 4 22 21 t h h 8 11 10 9 14 13 7 3 3 7 5 6 6 20 19 t bi 627t500/ 1250 (soic) t t t t t rx rx rx v cc1 812 7 v cc2 dtr (108) dx dx dx 4 0.2 f 3 22 0.2 f 0.2 f 0.2 f 0.1 f 23 24 1 2 21 0.1 f lt1134a lt1134a 43 22 0.1 f 23 24 1 0.1 f 19 13 13 ltc1346a ?ta08 50 ? = 125 ? t 50 ? dx dx 17 optional signals dx 15 dx 20 rx 18 rx 16 rx 14 5 7 9 11 6 8 10 12 20 18 16 14 21 19 17 15 6 8 10 12 5 7 9 11 rx rx rx rx rx dx dx dx dx c c rts (105) e e dsr (107) d d cts (106) f f dcd (109) nn nn tm (142) n n rdl (140) l l llb (141) iso 2593 34-pin dte/dce interface connector iso 2593 34-pin dte/dce interface connector
10 ltc1346a 1346afa applicatio n s i n for m a tio n wu u u ltc485 7v to 7v gnd potential difference v cc1 5v 100 100 aa b b gnd ltc1346a ?f09 ltc1346a v cc2 5v gnd ttl in ttl out v ee ?v + figure 9. rs422/rs485 receiver interface ltc1346 ?f10 receiver output 5v/div a b 10v ?v 0v 0v 5v receiver input 5v/div receiver output 5v/div 15v 5v 0v ltc1346 ?f11 10v 5v 0v a b receiver input 5v/div figure 10. 7v common mode figure 11. 12v common mode multiprotocol application the ltc1346a can be used in multiprotocol applications where v.35, rs232 and rs422 (used in rs530, rs449 among others) signals may appear at the same port. the ltc1346a switched current source driver is not compatible with rs232 or rs422. however, the outputs when disabled can share lines with rs232 drivers with a shutdown feature such as the lt1030 and rs422 drivers with a disable feature such as the ltc486/ltc487 (figure 12a). the ltc1346a driver will not be damaged or load the shared lines when disabled. the ltc1346a receiver can receive v.35, rs232 and rs422 signals as shown in figure 12b. the ltc1346a receiver is directly compatible with v.35 and rs422. for rs232 signal, the noninverting input of the receiver should be grounded. because the line termination for each of the protocols is different, some form of termination switching should be included, either the connector (as shown in figures 12a and 12b) or on the pcb.
11 ltc1346a 1346afa information furnished by linear technology corporation is believed to be accurate and reliable. however, no responsibility is assumed for its use. linear technology corporation makes no represen- tation that the interconnection of its circuits as described herein will not infringe on existing patent rights. applicatio n s i n for m a tio n wu u u figure 12a. multiprotocol transmitter lt1030 ltc487 ltc1346a connector 125 ? 50 ? v.35 differential connection with termination rs422 differential connection rs232 connection no connection 1346a f12a logic input 50 ? figure 12b. multiprotocol receiver ltc1346a 1346a f12b logic output 125 ? 100 ? 5k 50 ? 50 ? connector v.35 differential connection with termination rs422 differential connection with termination rs232 connection with termination
12 ltc1346a 1346afa u package descriptio sw package 24-lead plastic small outline (wide 0.300) (ltc dwg # 05-08-1620) related parts dimensions in inches (millimeters) unless otherwise noted. lw/tp 1002 1k rev a ?printed in usa ? l inear technology corporation 1995 linear technology corporation 1 630 mccarthy blvd., milpitas, ca 95035-7417 (408) 432-1900 fax: (408) 434-0507 www.linear.com part number description comments lt1134a 5v only, 4-driver/4-receiver rs232 transceiver forms complete v.35 interface with ltc1346a ltc1334 5v only, configurable rs232/rs485 transceiver includes on-chip charge pump ltc1344/ltc1344a multiprotocol cable terminator software selectable, supports v.35, v.36, v.28, eia-530, eia-530-a, rs449, x.21 ltc1544 4-driver, 4-receiver multiprotocol transceiver 5v supply, supports v.35, v.36, v.28, eia-530, eia-530-a, rs449, x.21 ltc1545 5-driver, 5-receiver multiprotocol transceiver 5v supply, supports v.35, v.36, v.28, eia-530, eia-530-a, rs449, x.21 ltc1546 3-driver, 3-receiver multiprotocol transceiver 5v supply, supports v.35, v.36, v.28, eia-530, eia-530-a, with termination rs449, x.21 ltc2844 3.3v, 4-driver, 4-receiver multiprotocol transceiver 3.3v supply, supports v.35, v.36, v.28, eia-530, eia-530-a, rs449, x.21 ltc2845 3.3v, 5-driver, 5-receiver multiprotocol transceiver 3.3v supply, supports v.35, v.36, v.28, eia-530, eia-530-a, rs449, x.21 ltc2846 3.3v, 3-driver, 3-receiver multiprotocol transceiver 3.3v supply, supports v.35, v.36, v.28, eia-530, eia-530-a, with termination rs449, x.21 s24 (wide) 0502 note 3 .598 ?.614 (15.190 ?15.600) note 4 22 21 20 19 18 17 16 15 1 23 4 5 6 78 .394 ?.419 (10.007 ?10.643) 910 13 14 11 12 n/2 23 24 n .037 ?.045 (0.940 ?1.143) .004 ?.012 (0.102 ?0.305) .093 ?.104 (2.362 ?2.642) .050 (1.270) bsc .014 ?.019 (0.356 ?0.482) typ 0 ?8 typ note 3 .009 ?.013 (0.229 ?0.330) .016 ?.050 (0.406 ?1.270) .291 ?.299 (7.391 ?7.595) note 4 45 .010 ?.029 (0.254 ?0.737) .420 min .325 .005 recommended solder pad layout .045 .005 n 123 n/2 .050 bsc .030 .005 typ .005 (0.127) rad min inches (millimeters) note: 1. dimensions in 2. drawing not to scale 3. pin 1 ident, notch on top and cavities on the bottom of packages are the manufacturing options. the part may be supplied with or without any of the options 4. these dimensions do not include mold flash or protrusions. mold flash or protrusions shall not exceed .006" (0.15mm)

▲Up To Search▲

Price & Availability of LTC1346A-15

	To Download LTC1346A-15 Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .