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general description the max3172/max3174 contain five software-selec- table multiprotocol cable termination networks. each network is capable of terminating v.11 (rs-422, rs- 530, rs-530a, rs-449, v.36, and x.21) with a 100 ? dif- ferential load, v.35 with a t-network load, or v.28 (rs-232) and v.10 (rs-423) with an open circuit load for use with transceivers having on-chip termination. the devices replace discrete resistor termination net- works and expensive relays required for multiprotocol termination. the max3172/max3174, along with the max3170 and max3171/max3173, form a complete +3.3v software-selectable dte or dce interface port supporting v.11/rs-422, rs-530, rs-530a, v.36/rs- 449, v.35, v.28/rs-232, v.10/rs-423, and x.21 serial interfaces. in addition to the five multiprotocol cable termination networks, the max3172/max3174 contain a 1tx/1rx multiprotocol transceiver designed to use v+ and v- generated by the max3171/max3173 charge pump. the max3172/max3174 transceiver is software selec- table between v.10 and v.28 modes of operation. the max3172 features 10? deglitching on the v.10/v.28 receiver input to facilitate unterminated operation, while the max3174 is used in applications that do not require deglitching on the serial handshake signals. these devices are available in a 28-pin ssop package. ________________________applications data networking pci cards csu and dsu telecommunications data routers features ? industry? first +3.3v multiprotocol termination networks and transceivers ? certified tbr-1 and tbr-2 compliant (net1 and net2) ? support v.28 (rs-232), v.11 (rs-422, rs-530, rs- 530a, rs-449, v.36, and x.21), v.10 and v.35 ? 3v/5v logic-compatible i/o ? software-selectable dte/dce ? replace discrete resistor termination networks and expensive relays ? 10? receiver input deglitching (max3172 only) ? available in small 28-pin ssop package ? transmitter output fault protected to ?5v, tolerates cable miswiring max3172/max3174 +3.3v multiprotocol software-selectable cable terminators and transceivers ________________________________________________________________ maxim integrated products 1 19-1801; rev 2; 6/04 ordering information part temp range pin-package max3172 cai 0 c to +70 c 28 ssop MAX3172EAI -40 c to +85 c 28 ssop max3174 cai 0 c to +70 c 28 ssop d1 d2 d3 r1 r2 r3 max3170 rxd rxc txd txc scte d1 r4 d4 d2 d3 r1 r2 r3 max3171 max3173 max3172 max3174 cts dsr rts dtr ll dcd cts b cts a dsr b dsr a dcd b dcd a dtr b dtr a rts b rts a shield sg ll a rxd a rxd b rxc b rxc a txc b txc a scte b scte a txd b txd a db-25 connector 13 5 10 8 22 6 23 20 19 4 1 7 16 18 3 9 17 12 15 11 24 14 2 t ypical operating circuit pin configuration appears at end of data sheet. for price, delivery, and to place orders, please contact maxim distribution at 1-888-629-4642, or visit maxim? website at www.maxim-ic.com.
max3172/max3174 +3.3v multiprotocol software-selectable cable terminators and transceivers 2 _______________________________________________________________________________________ absolute maximum ratings electrical characteristics (v cc = +3.3v 5%, t a = t min to t max . typical values are at v cc = +3.3v, t a = +25?, unless otherwise noted. see note 2 for v+ and v- input voltage conditions.) stresses beyond those listed under ?bsolute maximum ratings?may cause permanent damage to the device. these are stress rating s only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specificatio ns is not implied. exposure to absolute maximum rating conditions for extended periods may affect device reliability. note 1: v+ and v- can have maximum magnitudes of 7v, but their absolute difference cannot exceed 13v. (all voltages referenced to gnd unless otherwise noted.) supply voltages v cc ......................................................................-0.3v to +4v v+ (note 1) ..........................................................-0.3v to +7v v- (note 1) ...........................................................+0.3v to -7v v+ to v- (note 1) ...............................................................13v logic input voltages m0, m1, m2, dce/ dte, invert, t4in ................-0.3v to +6v logic output voltages r4out...................................................-0.3v to (v cc + 0.3v) short-circuit duration............................................continuous transmitter outputs t4out ................................................................-15v to +15v short-circuit duration ........................................................60s receiver input r4ina .................................................................-15v to +15v termination network inputs (applied individually) r_a, r_b ............................................................-15v to +15v continuous power dissipation (t a = +70?) 28-pin ssop (derate 9.52mw/? above +70?) ........762mw operating temperature range max3172cai/max3174cai ...............................0? to +70? MAX3172EAI...................................................-40? to +85? junction temperature ......................................................+150? storage temperature range .............................-65? to +150? lead temperature (soldering, 10s) .................................+300? parameter symbol conditions min typ max units dc characteristics all modes v.10 receiver inactive 80 200 supply current (digital inputs = gnd or v cc ) i cc all modes v.10 receiver active 400 750 ? no-cable mode 0.2 1.0 v.10/v.11/v.28/v.35 modes unloaded 0.5 2.5 v.10/v.11 modes t4out loaded 11.0 14.0 v+ supply current (t4in = gnd) i v+ v.28/v.35 modes t4out loaded 3.0 5.0 ma no-cable mode -0.4 -1.0 v.10/v.11/v.28/v.35 modes unloaded -0.8 -2.5 v.10/v.11 modes t4out loaded -11.0 -14.0 v- supply current (t4in = v cc ) i v- v.28/v.35 modes t4out loaded -3.0 -5.0 ma terminator networks (r_a, r_b) differential-mode impedance v.35 mode figure 1, -2v v cm +2v 90 104 110 ? common-mode impedance v.35 mode figure 2, -2v v cm +2v 135 153 165 ? differential-mode impedance v.11 mode figure 1, -7v v cm +7v 100 104 110 ? network off impedance i z switches open, -15v v a +15v, v b = v a , v b = gnd or v b floating 50 150 k ? logic inputs (m0, m1, m2, invert, dce/ dte , t4in) input high voltage v ih 2.0 v input low voltage v il 0.8 v logic input current i ih , i il v in = v cc or gnd ? ?
max3172/max3174 +3.3v multiprotocol software-selectable cable terminators and transceivers _______________________________________________________________________________________ 3 electrical characteristics (continued) (v cc = +3.3v 5%, t a = t min to t max . typical values are at v cc = +3.3v, t a = +25?, unless otherwise noted. see note 2 for v+ and v- input voltage conditions.) parameter symbol conditions min typ max units logic output (r4out) output high voltage v oh i source = 1.0ma v cc - 1.0 v output low voltage v ol i sink = 1.6ma 0.4 v rise or fall time t r , t f 10% to 90%, c l = 15pf 15 ns r4out = gnd 30 50 100 output leakage current (receiver output three-stated) r4out = v cc 0.1 1 ? transmitter output (t4out) output leakage current i z -0.25v < v t4out < +0.25v, power-off or no-cable mode -100 100 ? data rate v.10/v.28 240 kbps receiver input (r4ina) minimum pulse width passed 5 receiver glitch rejection (max3172 only) maximum pulse width rejected 15 ? v.10 enabled, -10v v r4ina +10v 20 40 receiver input resistance r in v.28 enabled, -15v v r4ina +15v 3 5 7 k ? max3172 64 data rate max3174 240 kbps v.10 transmitter output voltage swing v odo r l = 3.9k ? , figure 3 4.0 4.4 6.0 v loaded output voltage swing v odl r l = 450 ? , figure 3 0.9 v odo v short-circuit current i sc t4out = gnd 100 150 ma rise or fall time t r , t f 10% to 90%, r l = 450 ? , c l = 100pf, figure 3 2s transmitter propagation delay t phl , t plh r l = 450 ? , c l = 100pf, figure 3 2 ? data skew | t phl - t plh | r l = 450 ? , c l = 100pf, figure 3 50 ns v.10 receiver threshold voltage v th 25 100 250 mv input hysteresis ? v th 15 mv max3172 5 10 15 s receiver propagation delay t phl , t plh figure 4 max3174 60 120 ns max3172cai 0.5 4 MAX3172EAI 0.5 5 ? data skew | t phl - t plh | figure 4 max3174 5 16 ns
max3172/max3174 +3.3v multiprotocol software-selectable cable terminators and transceivers 4 _______________________________________________________________________________________ electrical characteristics (continued) (v cc = +3.3v 5%, t a = t min to t max . typical values are at v cc = +3.3v, t a = +25?, unless otherwise noted. see note 2 for v+ and v- input voltage conditions.) parameter symbol conditions min typ max units v.28 transmitter r l = 3k ? , figure 3 5.0 5.4 output voltage swing v o open circuit, figure 3 6.5 v short-circuit current i sc t4out = gnd 25 60 ma max3172cai max3174cai 430 r l = 3k ? , c l = 2500pf measured from +3v to -3v or -3v to +3v, figure 3 MAX3172EAI 3 30 output slew rate sr r l = 7k ? , c l = 150pf measured from +3v to -3v or -3v to +3v, figure 3 630 v/? transmitter propagation delay t phl , t plh 1s data skew | t phl - t plh | 100 ns v.28 receiver input threshold low v il 1.1 0.8 v input threshold high v ih 2.0 1.6 v input hysteresis v hys 0.5 v max3172 5 10 15 s receiver propagation delay t phl , t plh figure 4 max3174 200 ns max3172cai 0.5 4 MAX3172EAI 0.5 5 ? data skew | t phl - t plh | figure 4 max3174 100 ns note 2: the charge pump on the max3171/max3173 can supply v+ and v- to the max3172/max3174. the v+ and v- input levels vary with the mode of chipset operation as follows: v.35/v.28 modes: +5.55v v+ +6.50v, -6.50v v- -5.45v typical operation: v+ = +5.90v, v- = -5.80v v.10/v.11 modes: +4.20v v+ +5.0v, -4.60v v- -3.80v typical operation: v+ = +4.60v, v- = -4.20v the max3171/max3173 are guaranteed to provide these v+/v- supply levels.
max3172/max3174 +3.3v multiprotocol software-selectable cable terminators and transceivers _______________________________________________________________________________________ 5 0 14 12 18 16 22 20 24 v.28 slew rate vs. load capacitance max3172-01 load capacitance (pf) slew rate (v/ s) 0 500 1000 1500 3000 10 8 6 4 2 2500 2000 +slew -slew r l = 3k ? v.28 60kbps transmitter waveform (3k ? /1000pf load) max3172-02 10 s/div t4in 5v/div t4out 5v/div 0 5v 0 5v -5v 0 0.5 1.5 1.0 2.0 2.5 0 1000 500 1500 2000 2500 3000 v.10 rise and fall times vs. load capacitance max3172-03 load capacitance (pf) rise and fall times ( s) fall time rise time r l = 450 ? t ypical operating characteristics (v cc = +3.3v (see note 2 in electrical characteristics table), t a = +25?, unless otherwise noted.) v.10 60kbps transmitter waveform (450 ? /100pf) max3172-04 10 s/div 0 5v 0 5v -5v 5v/div t4out 5v/div t4in 100 102 101 104 103 106 105 107 109 108 110 -10 10 20 30 0405 0607080 v.11/v.35 differential-mode impedance vs. temperature max3172-05 temperature ( c) differential-mode impedance ( ? ) v cm = -7v v cm = 0 v cm = +7v 100 103 102 101 105 104 109 108 107 106 110 -7 -5 -3 -1 1357 v.11/v.35 differential-mode impedance vs. common-mode voltage max3172-06 common-mode voltage (v) differential-mode impedance ( ? )
max3172/max3174 +3.3v multiprotocol software-selectable cable terminators and transceivers 6 _______________________________________________________________________________________ 147 149 148 151 150 153 152 154 -10 10 20 0304 050607080 v.35 common-mode impedance vs. temperature max3172-09 temperature ( c) common-mode impedance ( ? ) v cm = -2.0v v cm = 2.0v v cm = 0 135 145 140 155 150 160 165 5.5 5.9 5.7 6.1 6.3 6.5 v.35 common-mode impedance vs. v+ max3172-11 v+ (v) common-mode impedance ( ? ) 135 145 140 155 150 160 165 -6.6 -6.2 -6.0 -6.4 -5.8 -5.6 -5.4 v.35 common-mode impedance vs. v- max3172-12 v- (v) common-mode impedance ( ? ) 148 149 150 151 152 153 154 -2.0 -1.0 -1.5 -0.5 0 0.5 1.0 1.5 2.0 v.35 common-mode impedance vs. common-mode voltage max3172-10 common-mode voltage (v) common-mode impedance ( ? ) 105.0 104.5 104.0 103.5 103.0 4.2 4.8 4.4 4.6 5.0 5.2 5.4 v.11/v.35 differential-mode impedance vs. v+ max3172-07 v+ (v) differential-mode impedance ( ? ) 105.0 104.5 104.0 103.5 103.0 -5.4 -4.4 -4.6 -5.0 -5.2 -4.8 -4.2 -4.0 -3.8 -3.6 v.11/v.35 differential-mode impedance vs. v- max3172-08 v- (v) differential-mode impedance ( ? ) t ypical operating characteristics (continued) (v cc = +3.3v (see note 2 in electrical characteristics table), t a = +25?, unless otherwise noted.)
max3172/max3174 +3.3v multiprotocol software-selectable cable terminators and transceivers _______________________________________________________________________________________ 7 figure 1. v.11 or v.35 differential impedance measurement figure 2. v.35 common-mode impedance measurement v cm = 2v r2 52 ? r1 52 ? s1 on a b s2 on ohmmeter r3 127 ? figure 3. v.10/v.28 driver test circuit c l r l t figure 4. v.10/v.28 receiver test circuit t est circuits v cm = 7v or 2v a b s2 off ohmmeter r2 52 ? r1 52 ? s1 on r3 127 ? 15pf tr
max3172/max3174 +3.3v multiprotocol software-selectable cable terminators and transceivers 8 _______________________________________________________________________________________ pin description pin name function 1m 2m ode-select pin (see tables 1 and 3 for detailed information) 2m 1m ode-select pin (see tables 1 and 3 for detailed information) 3m 0m ode-select pin (see tables 1 and 3 for detailed information) 4v cc +3.3v supply voltage ( 5%). bypass v cc to gnd with a 0.1 f capacitor. 5 r5a termination network 5 node a 6 r5b termination network 5 node b 7 t4in transmitter cmos input 8 r4out receiver cmos output 9,18, 22 gnd ground 10 r4b termination network 4 node b 11 r4a termination network 4 node a 12 r3c termination network 3 node c 13 r3b termination network 3 node b 14 r3a termination network 3 node a 15 r1a termination network 1 node a 16 r1b termination network 1 node b 17 r1c termination network 1 node c 19 r2c termination network 2 node c 20 r2b termination network 2 node b 21 r2a termination network 2 node a 23 r4ina inverting receiver input 24 v- negative supply (connect to v- pin of max3171/max3173). bypass v- to gnd with a 0.1 f capacitor. 25 t4out inverting transmitter output 26 v+ positive supply (connect to v+ pin of max3171/max3173). bypass v+ to gnd with a 0.1 f capacitor. 27 dce/ dte dce/ dte mode-select pin. logic level low selects dte interface. see tables 1 and 3 for detailed information. 28 invert mode-select pin (inverts functionality of dce/ dte input for t4/r4). see tables 1 and 3 for detailed information.
max3172/max3174 +3.3v multiprotocol software-selectable cable terminators and transceivers _______________________________________________________________________________________ 9 detailed description the max3172/max3174 contain five software-selectable multiprotocol cable termination networks. each network is capable of terminating v.11 transceivers (rs-422, rs- 530, rs-530a, rs-449, v.36, and x.21) with a 100 ? dif- ferential load, v.35 transceivers with a t-network load, or v.28 (rs-232) and v.10 transceivers (rs-423) with an open circuit load. the max3172/max3174, along with the max3170 and max3171/max3173, form a complete +3.3v software-selectable dte or dce interface port sup- porting v.11/rs-422, rs-530, rs-530a, v.36/rs-449, v.35, v.28/rs-232, v.10/rs-423, and x.21 serial inter- faces. the max3172/max3174 also contain a multiprotocol transceiver that is software-selectable between v.10 and v.28 operation modes. this transceiver is intended as the handshake signal i/o in a dce/dte port application, and is designed to use v+ and v- levels generated by the max3171/max3173 charge pump. the max3172 fea- tures 10? deglitching on the v.10/v.28 receiver input to allow unterminated operation. the max3174 is used in applications that do not require deglitching on the serial handshake signals. no-cable mode the max3172/max3174 enter no-cable mode when the mode-select inputs are all high (m0 = m1 = m2 = 1). in this mode, the driver, receiver, and bias circuitry are dis- abled, and the supply current drops to less than 200?. in no-cable mode, all five termination networks are placed in the v.11 mode of operation (shorting pins r_a and r_b with a 100 ? resistor). the receiver output enters a high-impedance state in no-cable mode, allowing this output line to be shared with other receivers (the receiver output has an internal pullup resistor to pull the output high if not driven). also, in no-cable mode, the transmit- ter output enters a high-impedance state so that this out- put can be shared with other devices. cable termination the max3172/max3174 software-selectable resistor net- works are intended for use with the max3170 clock/data transceiver chip. the termination network is used for the v.11, v.35, and v.28 transmitters. the max3172/ max3174 provide the advantage of not having to build expensive termination networks from resistors and relays, manually changing termination modules, or building ter- mination networks into custom cables. each termination network can be in one of three modes: v.35, v.11, or high impedance (high-z) as shown in figure 5 (see table 2). for example, in v.35 mode, all five table 1. termination mode selection mode m2 m1 m0 dce/ dte invert r1 r2 r3 r4 r5 v.10/rs-423 0 0 0 0 x z z z z z rs-530a 0 0 1 0 x z z v.11 v.11 v.11 rs-530 0 1 0 0 x z z v.11 v.11 v.11 x.21 0 1 1 0 x z z v.11 v.11 v.11 v.35 1 0 0 0 x v.35 v.35 v.35 v.35 v.35 rs-449/v.36 1 0 1 0 x z z v.11 v.11 v.11 v.28/rs-232 1 1 0 0 x z z z z z no cable 1 1 1 0 x v.11 v.11 v.11 v.11 v.11 v.10/rs-423 0 0 0 1 x z z z z z rs-530a 0 0 1 1 x z z z v.11 v.11 rs-530 0 1 0 1 x z z z v.11 v.11 x.21 0 1 1 1 x z z z v.11 v.11 v.35 1 0 0 1 x v.35 v.35 v.35 v.35 v.35 rs-449/v.36 1 0 1 1 x z z z v.11 v.11 v.28/rs-232 1 1 0 1 x z z z z z no cable 1 1 1 1 x v.11 v.11 v.11 v.11 v.11 table 2. switch configuration by mode mode sw1 sw2 v.35 on on v.11 on off v.28/v.10 (z) off off
max3172/max3174 +3.3v multiprotocol software-selectable cable terminators and transceivers 10 ______________________________________________________________________________________ networks are configured to provide 100 ? differential impedance and 150 ? common-mode impedance to ter- minate the max3170 v.35 transmitter outputs and receiv- er inputs. termination mode selection the mode-select pins m0, m1, m2, and dce/ dte control the state of the five termination networks ( table 1 ). the mode-select table of the max3172/max3174 is compati- ble with the max3170 mode-select table so that the m0, m1, m2, and dce/ dte pins can be connected to the cor- responding pins on the max3170. for example, m2 = 1, m1 = 0, m0 = 0 corresponds to v.35 mode for both the max3172/max3174 and the max3170 clock/data trans- ceiver chip. r4/t4 mode selection the max3172/max3174 include a transceiver for use in applications requiring an extra serial handshake signal (for example, local loopback). the transceiver can be protocol m2 m1 m0 dce/ dte invert t4 r4 not used (default v.11) 0 0 0 0 0 z v.10 rs-530a 0 0 1 0 0 z v.10 rs-530 0 1 0 0 0 z v.10 x.21 0 1 1 0 0 z v.10 v.35 1 0 0 0 0 z v.28 rs-449/v.36 1 0 1 0 0 z v.10 v.28/rs-232 1 1 0 0 0 z v.28 no cable 1 1 1 0 0 z z not used (default v.11) 0 0 0 1 0 v.10 z rs-530a 0 0 1 1 0 v.10 z rs-530 0 1 0 1 0 v.10 z x.21 0 1 1 1 0 v.10 z v.35 1 0 0 1 0 v.28 z rs-449/v.36 1 0 1 1 0 v.10 z v.28/rs-232 1 1 0 1 0 v.28 z no cable 1 1 1 1 0 z z not used (default v.11) 0 0 0 0 1 v.10 z rs-530a 0 0 1 0 1 v.10 z rs-530 0 1 0 0 1 v.10 z x.21 0 1 1 0 1 v.10 z v.35 1 0 0 0 1 v.28 z rs-449/v.36 1 0 1 0 1 v.10 z v.28/rs-232 1 1 0 0 1 v.28 z no cable 1 1 1 0 1 z z not used (default v.11) 0 0 0 1 1 z v.10 rs-530a 0 0 1 1 1 z v.10 rs-530 0 1 0 1 1 z v.10 x.21 0 1 1 1 1 z v.10 v.35 1 0 0 1 1 z v.28 rs-449/v.36 1 0 1 1 1 z v.10 v.28/rs-232 1 1 0 1 1 z v.28 no cable 1 1 1 1 1 z z table 3. r4/t4 mode-select table
max3172/max3174 +3.3v multiprotocol software-selectable cable terminators and transceivers ______________________________________________________________________________________ 11 configured for v.10 or v.28 operation as a driver or receiver ( table 3 ). this mode-selection table is compati- ble for use with the max3170 (clock/data transceiver) and the max3171/max3173 (control transceiver). for example, if x.21 mode is selected in dce mode (m2 = 0, m1 = 1, m0 = 1, and dce/ dte = 1), the max3170, max3171/max3173, and max3172/max3174 trans- ceivers will all be placed in x.21 dce mode. fail-safe the max3172/max3174 guarantee a logic high receiver output when the receiver input is shorted to gnd or when it is connected to a terminated transmis- sion line with the driver disabled. the v.10 receiver threshold is between +25mv and +250mv. if the v.10 receiver input voltage is less than +25mv, r4out is logic high. if the v.10 receiver input is greater than +250mv, r4out is logic low. the v.28 receiver threshold is between +0.8v and +2.0v. if the v.28 receiver input voltage is less than +0.8v, r4out is logic high. if the receiver input is greater than +2.0v, r4out is logic low. if the driving transmitter is disabled or disconnected, the receiver? input voltage is pulled to zero by its internal termination. with the receiver thresholds of the max3172/max3174, this results in a logic high. applications information older multiprotocol cable termination implementations have been constructed using expensive relays with dis- crete resistors, custom cables with built-in termination, or complex circuit board configurations to route signals to the correct termination. the max3172/max3174 pro- vide a simple solution to this termination problem. all required termination configurations are software selec- table using four mode-control input pins (m2, m1, m0, and dce/ dte ). v.11 termination for high-speed data transmission, the v.11 specifica- tion recommends terminating the cable at the receiver 100 ? min a b c a b c generator balanced interconnecting cable cable termination receiver load figure 6. typical v.11 interface a b s2 off v.11 mode v.35 mode high-z mode a c* b s2 on s1 off a b s2 off c* c* *node c is provided in networks 1,2,3. r2 52 ? r1 52 ? s1 on r3 127 ? r2 52 ? r1 52 ? s1 on r3 127 ? r2 52 ? r1 52 ? r3 127 ? figure 5. max3172/max3174 termination network configurations
max3172/max3174 +3.3v multiprotocol software-selectable cable terminators and transceivers 12 ______________________________________________________________________________________ with a minimum of a 100 ? resistor ( figure 6 ). this resis- tor, although not required, prevents reflections from corrupting transmitted data. in figure 7 , the max3172/max3174 are used to termi- nate the v.11 receiver. internal to the max3172/ max3174, s1 is closed and s2 is open to present a 104 ? typical differential resistance and high-z com- mon-mode impedance. s3 opens to disable the max3170? internal v.28 termination. the v.11 specification allows for signals with common- mode variations of ?v with differential signal ampli- tudes from 2v to 6v. also, data rates may be as high as 10mbps. the max3172/max3174 maintain steady ter- mination impedance between 100 ? and 110 ? over these conditions. v.35 termination figure 8 shows a standard v.35 interface. the genera- tor and the load must both present a 100 ? ? 0 ? differ- ential impedance and a 150 ? ? 5 ? common-mode impedance (as shown by the resistive t-networks in figure 8 ). the v.35 driver generates a current output (typically ?1ma) that develops an output voltage between 440mv and 660mv across the load termina- tion networks. r6 10k ? r8 5k ? r3 127 ? r2 52 ? r1 52 ? a b c a b gnd r5 30k ? r7 10k ? r4 30k ? max3172 max3174 max3170 s3 s2 s1 receiver 50 ? 50 ? 125 ? 50 ? 50 ? 125 ? a b c a b c generator balanced interconnecting cable cable termination receiver load figure 8. typical v.35 interface figure 7. v.11 termination and internal resistance networks
max3172/max3174 +3.3v multiprotocol software-selectable cable terminators and transceivers ______________________________________________________________________________________ 13 in figure 9 , the max3172/max3174 are used to imple- ment the resistive t-network that is needed to properly terminate the v.35 driver and receiver. internal to the max3172/max3174, s1 and s2 are closed to connect the t-network resistors to the circuit. the v.28 termina- tion resistor, internal to the max3170, is disabled by opening s3 to avoid interference with the t-network impedance. the v.35 specification allows for ?v of ground differ- ence between the v.35 generator and v.35 load. the v.35 data rates may be as high as 10mbps. the max3172/max3174 maintain correct terminal imped- ances over these conditions. v.35 emi reduction for applications where emi reduction is especially important, the max3172/max3174 termination net- works provide a pin for shunting common-mode driver currents to gnd ( figure 10 ). mismatches between a and b driver output propagation delays create a com- mon-mode disturbance on the cable. this common- mode energy can be shunted to gnd by placing a 100pf capacitor (c1 to gnd) from the center point of the t-network termination (r1c, r2c, and r3c). v.28 termination most industry-standard v.28 receivers (including the max3170) do not require external termination because the receiver includes an internal 5k ? termination resis- tor. when the max3172/max3174 are placed in v.28 mode, all five of the termination networks are placed in a high-z mode. in high-z mode, the max3172/ max3174 termination networks will not interfere with the max3170's internal 5k ? termination. figure 9. v.35 termination and internal resistance networks r6 10k ? r8 5k ? r3 127 ? r2 52 ? r1 52 ? a b c a b gnd r5 30k ? r7 10k ? r4 30k ? max3172 max3174 max3170 s3 s2 s1 receiver figure 10. v.35 driver r3 127 ? r2 52 ? r1 52 ? a b c(gnd) max3172 max3174 s1 s2 c1 100pf driver r_c
max3172/max3174 +3.3v multiprotocol software-selectable cable terminators and transceivers 14 ______________________________________________________________________________________ in figure 11 , the max3170 and max3172/max3174 are placed in v.28 mode. switches s1 and s2 are opened on the max3172/max3174 to place the network in high- z mode. switch s3 is closed on the max3170 to enable the 5k ? terminating resistor. v.28 interface the v.28 interface is an unbalanced single-ended inter- face ( figure 12 ). the v.28 driver generates a minimum of ?v across the load impedance between a' and c'. the v.28 receiver specification calls for input trip points at ?v. to aid in rejecting system noise, the max3170 v.28 receiver has a typical hysteresis of 0.5v. also, the max3172/max3174 have more tightly specified input trip points to guarantee fail-safe operation (see fail- safe ). the max3172/max3174 v.28 receiver provides an internal 5k ? termination resistance. v.10 interface the v.10 interface ( figure 12 ) is an unbalanced single- ended interface capable of driving a 450 ? load. the v.10 driver generates a minimum voltage of ?v (v odo ) across a' and c' when unloaded and a mini- mum voltage of ?.9 ? v odo when loaded with 450 ? . the v.10 receiver input trip threshold is defined between +300mv and -300mv with input impedance characteristics shown in figure 13 . the max3172/max3174 v.10 mode receiver has a threshold between +25mv and +250mv to ensure that the receiver has proper fail-safe operation (see fail- safe ). to aid in rejecting system noise, the max3172/ max3174 v.10 receiver has a typical hysteresis of 15mv. switch s3 in figure 14 is open in v.10 mode to disable the 5k ? v.28 termination at the receiver input. receiver glitch rejection to allow operation in an unterminated or otherwise noisy system, the max3172 features 10? of receiver input glitch rejection. the glitch-rejection circuitry blocks the reception of high-frequency noise with a bit period less than 5? while receiving low-frequency sig- nals with a bit period greater than 15?, allowing glitch- free operation in unterminated systems at up to 64kbps. figure 12. typical v.28 and v.10 interface a c a c generator unbalanced interconnecting cable cable termination receiver load figure 11. v.28 termination and internal resistance networks r6 10k ? r8 5k ? r3 127 ? r2 52 ? r1 52 ? a b c a b gnd r5 30k ? r7 10k ? r4 30k ? max3172 max3174 max3170 s3 s2 s1 receiver figure 13. v.10 receiver input impedance -3.25ma 3.25ma -10v +10v -3v +3v v z i z
max3172/max3174 +3.3v multiprotocol software-selectable cable terminators and transceivers ______________________________________________________________________________________ 15 the max3174 does not have this glitch rejection and can be operated at frequencies up to 240kbps if prop- erly terminated. dce vs. dte operation figure 15 illustrates a dce or dte controller-selectable interface. the dce/ dte input switches the max3172/ max3174s?mode of operation. logic high selects dce, which enables driver 4 on the max3172/max3174 (invert = 0), driver 3 on the max3171/max3173, and driver 3 on the max3170. a logic low selects dte, which enables receiver 4 on the max3172/max3174 (invert = 0), receiver 1 on the max3171/max3173, and receiver 1 on the max3170. this application requires only one db-25 connector. see figure 15 for complete signal routing in dce and dte modes. for example, driver 4 routes the ll(dce) signal to pin 18 in dce mode, while in dte mode, receiver 4 routes pin 18 to the ll(dte) signal. complete multiprotocol x.21 interface a complete dte-to-dce interface operating in x.21 mode is shown in figure 16 . the max3172/max3174 ter- minate the v.11 clock and data signals, and its transceiv- er carries the local loopback (ll) signal. the max3170 carries the clock and data signals, and the max3171/max3173 carry the control signals. the control signals generally do not require external termination. compliance testing a european standard en45001 test report is available for the max3170?ax3174 chipset. a copy of the test report is available from maxim upon request. r6 10k ? r8 5k ? a c a gnd r5 30k ? r7 10k ? r4 30k ? max3172 max3174 s3 receiver figure 14. v.10 internal resistance networks
max3172/max3174 +3.3v multiprotocol software-selectable cable terminators and transceivers 16 ______________________________________________________________________________________ figure 15. multiprotocol dce/dte port d1 d2 d3 r1 r2 r3 max3170 rxd(dte) txd(dce) rxc(dte) scte(dce) ll(dte) ll(dce) txd(dte) rxd(dce) txc(dte) txc(dce) scte(dte) rxc(dce) m1 m2 m0 dce/dte m1 m2 m0 dce/dte d1 r4 d4 d2 d3 r1 r2 r3 max3171 max3173 m1 m2 m0 dce/dte cts(dte) rts(dce) dsr(dte) dtr(dce) rts(dte) cts(dce) dtr(dte) dsr(dce) dcd(dte) dcd(dce) m2 m1 m0 dce/dte cts b cts a dsr b dsr a dcd b dcd a dtr b dtr a rts b rts a shield sg ll a rxd b rxd a rxc b rxc a txc b txc a scte b scte a txd b txd a db-25 connector dte dce rts b rts a dtr b dtr a dcd b dcd a dsr b dsr a cts b cts a ll a txd b txd a scte b scte a txc b txc a rxc b rxc a rxd b rxd a 13 5 10 8 22 6 23 20 19 4 1 7 18 16 3 9 17 12 15 11 24 14 2 max3172 max3174
max3172/max3174 +3.3v multiprotocol software-selectable cable terminators and transceivers ______________________________________________________________________________________ 17 d1 d2 d3 r3 r2 r1 d3 d2 d1 d4 txd scte txc rxc rxd ll d4 r4 r4 r1 r2 r3 103 ? 103 ? 103 ? 103 ? 103 ? max3170 max3172 max3174 max3172 max3174 max3170 d1 d2 d3 r3 r2 r1 d3 d2 d1 rts dtr dcd dsr cts r1 r2 r3 max3171 max3173 max3171 max3173 serial controller txd scte txc rxc rxd rts dtr dcd dsr cts ll serial controller txd scte txc rxc rxd rts dtr dcd dsr cts ll dce dte figure 16. dce-to-dte x.21 interface
max3172/max3174 +3.3v multiprotocol software-selectable cable terminators and transceivers 18 ______________________________________________________________________________________ pin configuration 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 invert dce/dte v+ t4out v- r4ina r1a gnd r2a r2b r2c gnd r1c r1b r3a r3b r3c r4a r4b gnd r4out t4in r5b r5a v cc m0 m1 m2 28 ssop top view max3172 max3174 chip information transistor count: 2506
+3.3v multiprotocol software-selectable cable terminators and transceivers maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a maxim product. no circu it patent licenses are implied. maxim reserves the right to change the circuitry and specifications without notice at any time. maxim integrated products, 120 san gabriel drive, sunnyvale, ca 94086 408-737-7600 ____________________ 19 2004 maxim integrated products printed usa is a registered trademark of maxim integrated products. max3172/max3174 ssop.eps package outline, ssop, 5.3 mm 1 1 21-0056 c rev. document control no. approval proprietary information title: notes: 1. d&e do not include mold flash. 2. mold flash or protrusions not to exceed .15 mm (.006"). 3. controlling dimension: millimeters. 4. meets jedec mo150. 5. leads to be coplanar within 0.10 mm. 7.90 h l 0 0.301 0.025 8 0.311 0.037 0 7.65 0.63 8 0.95 max 5.38 millimeters b c d e e a1 dim a see variations 0.0256 bsc 0.010 0.004 0.205 0.002 0.015 0.008 0.212 0.008 inches min max 0.078 0.65 bsc 0.25 0.09 5.20 0.05 0.38 0.20 0.21 min 1.73 1.99 millimeters 6.07 6.07 10.07 8.07 7.07 inches d d d d d 0.239 0.239 0.397 0.317 0.278 min 0.249 0.249 0.407 0.328 0.289 max min 6.33 6.33 10.33 8.33 7.33 14l 16l 28l 24l 20l max n a d e a1 l c h e n 1 2 b 0.068 package information (the package drawing(s) in this data sheet may not reflect the most current specifications. for the latest package outline info rmation, go to www.maxim-ic.com/packages .)

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