LTC1545 Software-Selectable Multiprotocol Transceiver U FEATURES DESCRIPTIO The LTC(R)1545 is a 5-driver/5-receiver multiprotocol transceiver. The LTC1545 and LTC1543 form the core of a complete software-selectable DTE or DCE interface port that supports the RS232, RS449, EIA530, EIA530-A, V.35, V.36 or X.21 protocols. Cable termination may be implemented using the LTC1344A software-selectable cable termination chip or by using existing discrete designs. The LTC1545 runs from a 5V supply and the charge pump on the LTC1543. The part is available in a 36-lead SSOP surface mount package. Software-Selectable Transceiver Supports: RS232, RS449, EIA530, EIA530-A, V.35, V.36, X.21 TUV/Detecon Inc. Certified NET1 and NET2 Compliant (Test Report No. NET2/071601/98) TBR2 Compliant (Test Report No. CTR2/071601/98) Software-Selectable Cable Termination Using the LTC1344A Complete DTE or DCE Port with LTC1543, LTC1344A Operates from Single 5V Supply with LTC1543 U APPLICATIO S Data Networking CSU and DSU Data Routers , LTC and LT are registered trademarks of Linear Technology Corporation. U TYPICAL APPLICATIO DTE or DCE Multiprotocol Serial Interface with DB-25 Connector RL TM RI LL CTS DSR DCD DTR RTS D2 D1 RXD TXC RXC D4 R5 R4 D3 R3 R2 TXD D2 D1 LTC1543 LTC1545 D5 SCTE D3 R3 R1 R2 R1 LTC1344A 21 25 * 18 13 5 22 6 10 8 23 20 19 4 1 16 3 9 17 12 15 11 24 14 2 TXD A (103) TXD B SCTE A (113) TXC A (114) SCTE B TXC B RXC A (115) RXC B RXD A (104) RXD B SG (102) SHIELD (101) RTS A (105) RTS B DTR A (108) DCD A (109) DTR B DCD B DSR A (107) CTS A (106) DSR B LL A (141) CTS B RI A (125) TM A (142) RL A (140) DB-25 CONNECTOR 7 *OPTIONAL 1545 TA01 1 LTC1545 U W U U W W W ABSOLUTE MAXIMUM RATINGS PACKAGE/ORDER INFORMATION (Note 1) Supply Voltage VCC ..................................................................... 6.5V VEE ........................................................ - 10V to 0.3V VDD ....................................................... - 0.3V to 10V Input Voltage Transmitters ........................... - 0.3V to (VCC + 0.3V) Receivers ............................................... - 18V to 18V Logic Pins .............................. - 0.3V to (VCC + 0.3V) Output Voltage Transmitters .................. (VEE - 0.3V) to (VDD + 0.3V) Receivers ................................ - 0.3V to (VCC + 0.3V) Short-Circuit Duration Transmitter Output ..................................... Indefinite Receiver Output .......................................... Indefinite VEE .................................................................. 30 sec Operating Temperature Range LTC1545C .............................................. 0C to 70C LTC1545I ........................................... - 40C to 85C Storage Temperature Range ................ - 65C to 150C Lead Temperature (Soldering, 10 sec)................. 300C TOP VIEW ORDER PART NUMBER VCC 1 36 VEE VDD 2 35 GND D1 3 D2 4 D3 5 R1 6 R2 7 R3 8 D4 9 34 D1 A D1 33 D1 B 32 D2 A D2 31 D2 B D3 LTC1545CG LTC1545IG 30 D3/R1 A 29 D3/R1 B 28 R2 A R1 27 R2 B R4 10 R2 M0 11 M1 12 26 R3 A 25 R3 B R3 24 D4 A M2 13 D4 DCE/DTE 14 23 R4 A R4 D4ENB 15 22 R5 A 21 D5 A R4EN 16 R5 R5 17 D5 18 20 VDD 19 VCC D5 G PACKAGE 36-LEAD PLASTIC SSOP TJMAX = 150C, JA = 65C/ W Consult factory for Military grade parts. ELECTRICAL CHARACTERISTICS The denotes specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25C. VCC = 5V, VDD = 8V, VEE = - 7V for V.28, - 5.5V for V.10, V.11 (Notes 2, 3) SYMBOL PARAMETER CONDITIONS ICC VCC Supply Current (DCE Mode, All Digital Pins = GND or VCC) RS530, RS530-A, X.21 Modes, No Load RS530, RS530-A, X.21 Modes, Full Load V.28 Mode, No Load V.28 Mode, Full Load No-Cable Mode, D4ENB = HIGH IEE VEE Supply Current (DCE Mode, All Digital Pins = GND or VCC) IDD PD MIN TYP MAX UNITS 2.7 110 1 1 10 5 150 3 3 500 mA mA mA mA A RS530, RS530-A, X.21 Modes, No Load RS530, X.21 Modes, Full Load RS530-A, Full Load V.28 Mode, No Load V.28 Mode, Full Load No-Cable Mode, D4ENB = HIGH 2.0 23 34 1 12 10 4.0 35 50 3 18 500 mA mA mA mA mA A VDD Supply Current (DCE Mode, All Digital Pins = GND or VCC) RS530, RS530-A, X.21 Modes, NoLoad RS530, RS530-A, X.21 Modes, Full Load V.28 Mode, No Load V.28 Mode, Full Load No-Cable Mode, D4ENB = HIGH 0.3 0.3 1 13.5 10 2 2 3 18 500 mA mA mA mA A Internal Power Dissipation (DCE Mode, (All Digital Pins = GND or VCC) RS530, RS530-A, X.21 Modes, Full Load V.28 Mode, Full Load Supplies 2 340 64 mW mW LTC1545 ELECTRICAL CHARACTERISTICS The denotes specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25C. VCC = 5V, VDD = 8V, VEE = - 7V for V.28, - 5.5V for V.10, V.11 (Notes 2, 3) SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS Logic Inputs and Outputs VIH Logic Input High Voltage VIL Logic Input Low Voltage IIN Logic Input Current 2 V 0.8 V D1, D2, D3, D4, D5 M0, M1, M2, DCE, D4ENB, R4EN = GND (LTC1545C) M0, M1, M2, DCE, D4ENB, R4EN = GND (LTC1545I) M0, M1, M2, DCE, D4ENB, R4EN = VCC - 100 - 120 - 50 - 50 10 - 30 - 30 10 A A A A 3 4.5 VOH Output High Voltage IO = - 4mA VOL Output Low Voltage IO = 4mA IOSR Output Short-Circuit Current 0V VO VCC IOZR Three-State Output Current M0 = M1 = M2 = VCC, 0V VO VCC - 50 V 0.3 0.8 V 40 50 mA 1 A V.11 Driver VODO Open Circuit Differential Output Voltage RL = 1.95k (Figure 1) VODL Loaded Differential Output Voltage RL = 50 (Figure 1) RL = 50 (Figure 1) 5 0.5VODO 2 V 0.67VODO V VOD Change in Magnitude of Differential Output Voltage RL = 50 (Figure 1) 0.2 V VOC Common Mode Output Voltage RL = 50 (Figure 1) 3 V VOC Change in Magnitude of Common Mode Output Voltage RL = 50 (Figure 1) 0.2 V ISS Short-Circuit Current VOUT = GND IOZ Output Leakage Current - 0.25V VO 0.25V, Power Off or No-Cable Mode or Driver Disabled t r, t f Rise or Fall Time LTC1545C (Figures 2, 5) LTC1545I (Figures 2, 5) t PLH Input to Output LTC1545C (Figures 2, 5) LTC1545I (Figures 2, 5) t PHL Input to Output t t SKEW 150 mA 1 100 A 2 2 15 15 25 35 ns ns 20 20 40 40 65 75 ns ns LTC1545C (Figures 2, 5) LTC1545I (Figures 2, 5) 20 20 40 40 65 75 ns ns Input to Output Difference, tPLH - tPHL LTC1545C (Figures 2, 5) LTC1545I (Figures 2, 5) 0 0 3 3 12 17 ns ns Output to Output Skew (Figures 2, 5) 3 ns V.11 Receiver VTH Input Threshold Voltage - 7V VCM 7V VTH Input Hysteresis - 7V VCM 7V IIN Input Current (A, B) - 10V VA,B 10V RIN Input Impedance - 10V VA,B 10V t r, t f Rise or Fall Time (Figures 2, 6) t PLH Input to Output LTC1545C (Figures 2, 6) LTC1545I (Figures 2, 6) 50 50 80 90 ns ns t PHL Input to Output LTC1545C (Figures 2, 6) LTC1545I (Figures 2, 6) 50 50 80 90 ns ns t Input to Output Difference, tPLH - tPHL LTC1545C (Figures 2, 6) LTC1545I (Figures 2, 6) 4 4 16 21 ns ns - 0.2 15 15 0 0 0.2 V 40 mV 0.66 mA 30 k 15 ns 3 LTC1545 ELECTRICAL CHARACTERISTICS The denotes specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25C. VCC = 5V, VDD = 8V, VEE = - 7V for V.28, - 5.5V for V.10, V.11 (Notes 2, 3) SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS VO Output Voltage Open Circuit, RL = 3.9k 4 VT Output Voltage RL = 450 (Figure 3) RL = 450 (Figure 3) 3.6 0.9VO ISS Short-Circuit Current VO = GND IOZ Output Leakage Current - 0.25V VO 0.25V, Power Off or No-Cable Mode or Driver Disabled t r, t f Rise or Fall Time RL = 450, CL = 100pF (Figures 3, 7) 2 s t PLH Input to Output RL = 450, CL = 100pF (Figures 3, 7) 1 s t PHL Input to Output RL = 450, CL = 100pF (Figures 3, 7) 1 s V.10 Driver 6 V 0.1 V 150 mA 100 A V.10 Receiver VTH Receiver Input Threshold Voltage VTH Receiver Input Hysteresis IIN Receiver Input Current - 10V VA 10V RIN Receiver Input Impedance - 10V VA 10V t r , tf Rise or Fall Time tPLH Input to Output tPHL t - 0.25 0.25 25 15 V 50 mV 0.66 mA 30 k (Figures 4, 8) 15 ns (Figures 4, 8) 55 ns Input to Output (Figures 4, 8) 109 ns Input to Output Difference, tPLH - tPHL (Figures 4, 8) 60 ns VO Output Voltage Open Circuit RL = 3k (Figure 3) ISS Short-Circuit Current VO = GND IOZ Output Leakage Current - 0.25V VO 0.25V, Power Off or No-Cable Mode or Driver Disabled SR Slew Rate RL = 3k, CL = 2500pF (Figures 3, 7) t PLH Input to Output RL = 3k, CL = 2500pF (Figures 3, 7) t PHL Input to Output RL = 3k, CL = 2500pF (Figures 3, 7) V.28 Driver 5 8.5 1 4 10 V V 150 mA 100 A 30 V/s 1.3 2.5 s 1.3 2.5 s 1.5 0.8 V 0.1 0.3 V 5 7 V.28 Receiver VTHL Input Low Threshold Voltage VTLH Input High Threshold Voltage VTH Receiver Input Hysterisis RIN Receiver Input Impedance - 15V VA 15V t r , tf Rise or Fall Time (Figures 4, 8) tPLH Input to Output (Figures 4, 8) 60 100 ns tPHL Input to Output (Figures 4, 8) 150 450 ns Note 1: 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 are negative. All voltages are referenced to device ground unless otherwise specified. 4 2 3 1.6 V 15 k ns Note 3: All typicals are given for VCC = 5V, VDD = 8V, VEE = - 7V for V.28, - 5.5V for V.10, V.11 and TA = 25C. LTC1545 U U U PIN FUNCTIONS VCC (Pins 1, 19): Positive Supply for the Transceivers. 4.75V VCC 5.25V. Connect a 1F capacitor to ground. VDD (Pins 2, 20): Positive Supply Voltage for V.28. Connect to VDD Pin 3 on LTC1543 or 8V supply. Connect a 1F capacitor to ground. R5 (Pin 17): CMOS Level Receiver 5 Output. D5 (Pin 18): TTL Level Driver 5 Input. D5 A (Pin 21): Driver 5 Output. R5 A (Pin 22): Receiver 5 Input. D1 (Pin 3): TTL Level Driver 1 Input. R4 A (Pin 23): Receiver 4 Input. D2 (Pin 4): TTL Level Driver 2 Input. D4 A (Pin 24): Driver 4 Input. D3 (Pin 5): TTL Level Driver 3 Input. R3 B (Pin 25): Receiver 3 Noninverting Input. R1 (Pin 6): CMOS Level Receiver 1 Output. R3 A (Pin 26): Receiver 3 Inverting Input. R2 (Pin 7): CMOS Level Receiver 2 Output. R2 B (Pin 27): Receiver 2 Noninverting Input. R3 (Pin 8): CMOS Level Receiver 3 Output. R2 A (Pin 28): Receiver 2 Inverting Input. D4 (Pin 9): TTL Level Driver 4 Input. D3/R1 B (Pin 29): Receiver 1 Noninverting Input and Driver 3 Noninverting Output. R4 (Pin 10): CMOS Level Receiver 4 Output. M0 (Pin 11): TTL Level Mode Select Input 0 with Pull-Up to VCC. M1 (Pin 12): TTL Level Mode Select Input 1 with Pull-Up to VCC. D3/R1 A (Pin 30): Receiver 1 Inverting Input and Driver 3 Inverting Output. D2 B (Pin 31): Driver 2 Noninverting Output. D2 A (Pin 32): Driver 2 Inverting Output. M2 (Pin 13): TTL Level Mode Select Input 2 with Pull-Up to VCC. D1 B (Pin 33): Driver 1 Noninverting Output. DCE/DTE (Pin 14): TTL Level Mode Select Input with Pull-Up to VCC. Logic high enables Driver 3. Logic low enables Receiver 1. GND (Pin 35): Ground. D4ENB (Pin 15): TTL Level Enable Input with Pull-Up to VCC. Logic low enables Driver 4. D1 A (Pin 34): Driver 1 Inverting Output. VEE (Pin 36): Negative Supply Voltage. Connect to VEE Pin 26 on LTC1543. Connect a 1F capacitor to ground. R4EN (Pin 16): TTL Level Enable Input with Pull-Up to VCC. Logic high enables Receiver 4. TEST CIRCUITS A B RL A VOD RL RL 100 CL 100pF B CL 100pF A R 15pF VOC 1545 F02 B 1545 F01 Figure 1. V.11 Driver Test Circuit Figure 2. V.11 Driver/Receiver AC Test Circuit 5 LTC1545 TEST CIRCUITS D D A A A R 15pF RL CL 1545 F04 1545 F03 Figure 3. V.10/V.28 Driver Test Circuit Figure 4. V.10/V.28 Receiver Test Circuit U W ODE SELECTIO LTC1545 MODE NAME M2 M1 M0 D1 D2 (Note 1) (Note 2) D3 D4 D5 (Note 1) R1 R2 R3 (Note 3) R4 R5 Not Used (Default V.11) 0 0 0 V.11 V.11 V.11 V.10 V.10 V.11 V.11 V.11 V.10 V.10 RS530A 0 0 1 V.11 V.10 V.11 V.10 V.10 V.11 V.10 V.11 V.10 V.10 RS530 0 1 0 V.11 V.11 V.11 V.10 V.10 V.11 V.11 V.11 V.10 V.10 X.21 0 1 1 V.11 V.11 V.11 V.10 V.10 V.11 V.11 V.11 V.10 V.10 V.35 1 0 0 V.28 V.28 V.28 V.28 V.28 V.28 V.28 V.28 V.28 V.28 RS449/V.36 1 0 1 V.11 V.11 V.11 V.10 V.10 V.11 V.11 V.11 V.10 V.10 V.28/RS232 1 1 0 V.28 V.28 V.28 V.28 V.28 V.28 V.28 V.28 V.28 V.28 D4ENB = 1, R4EN = 0 M0 = M1 = M2 = 1 1 1 1 Z Z Z Z Z Z Z Z Z Z Note 1: Driver 3 and Receiver 1 are enabled (and disabled) by DCE/DTE (Pin 14). Logic high enables Driver 3. Logic low enables Receiver 1. Note 2: Driver 4 is enabled by D4ENB = 0 (Pin 15). Note 3: Receiver 4 is enabled by R4EN = 1 (Pin 16). U W W SWITCHI G TI E WAVEFOR S 5V f = 1MHz : t r 10ns : t f 10ns 1.5V D 0V t PHL t PLH VO B-A -VO 1.5V 90% 50% VDIFF = V(B) - V(A) 10% 1/2 VO tr 90% 50% 10% tf A VO B t SKEW Figure 5. V.11 Driver Propagation Delays 6 t SKEW 1545 F05 LTC1545 U W W SWITCHI G TI E WAVEFOR S VOD2 B-A -VOD2 f = 1MHz : t r 10ns : t f 10ns 0V INPUT t PLH VOH R VOL 0V t PHL OUTPUT 1.5V 1.5V 1545 F06 Figure 6. V.11 Receiver Propagation Delays 3V 1.5V 1.5V D 0V t PHL VO t PLH 3V 3V 0V A 0V -3V -VO 1545 F07 -3V tf tr Figure 7. V.10, V.28 Driver Propagation Delays VIH 1.5V 1.5V A VIL t PHL VOH R VOL t PLH 1.5V 1.5V 1545 F08 Figure 8. V.10, V.28 Receiver Propagation Delays U W U U APPLICATIONS INFORMATION Overview Mode Selection The LTC1543/LTC1545 form the core of a complete software-selectable DTE or DCE interface port that supports the RS232, RS449, EIA530, EIA530-A, V.35, V.36 or X.21 protocols. Cable termination may be implemented using the LTC1344A software-selectable cable termination chip or by using existing discrete designs. The interface protocol is selected using the mode select pins M0, M1 and M2 (see the Mode Selection table). A complete DCE-to-DTE interface operating in EIA530 mode is shown in Figure 9. The LTC1543 of each port is used to generate the clock and data signals. The LTC1545 is used to generate the control signals along with LL (Local Loop-Back), RL (Remote Loop-Back), TM (Test Mode) and RI (Ring Indicate). The LTC1344A cable termination chip is used only for the clock and data signals because they must support V.35 cable termination. The control signals do not need any external resistors. For example, if the port is configured as a V.35 interface, the mode selection pins should be M2 = 1, M1 = 0, M0 = 0. For the control signals, the drivers and receivers will operate in V.28 (RS232) electrical mode. For the clock and data signals, the drivers and receivers will operate in V.35 electrical mode. The DCE/DTE pin will configure the port for DCE mode when high, and DTE when low. The interface protocol may be selected simply by plugging the appropriate interface cable into the connector. The mode pins are routed to the connector and are left unconnected (1) or wired to ground (0) in the cable as shown in Figure 10. 7 LTC1545 U U W U APPLICATIONS INFORMATION DTE SERIAL CONTROLLER LTC1543 DCE LTC1344A LTC1344A LTC1543 SERIAL CONTROLLER TXD D1 TXD 103 R3 TXD SCTE D2 SCTE 103 R2 SCTE R1 D3 TXC R1 103 TXC D3 TXC RXC R2 103 RXC D2 RXC RXD R3 103 RXD D1 RXD LTC1545 LTC1545 RTS D1 RTS R3 RTS DTR D2 DTR R2 DTR D3 R1 DCD R1 DCD D3 DCD DSR R2 DSR D2 DSR CTS R3 CTS D1 CTS LL TM RI RL LL D4 R4 TM R4 R5 D5 D4 RI D5 RL R5 LL TM RI RL 1545 F09 Figure 9. Complete Multiprotocol Interface in EIA530 Mode The internal pull-up current sources will ensure a binary 1 when a pin is left unconnected and that the LTC1543/ LTC1545 and the LTC1344A enter the no-cable mode when the cable is removed. In the no-cable mode the LTC1543/LTC1545 supply current drops to less than 200A and all LTC1543/LTC1545 driver outputs and LTC1344A resistive terminations are forced into a high impedance state. 8 The mode selection may also be accomplished by using jumpers to connect the mode pins to ground or VCC. Cable Termination Traditional implementations have included switching resistors with expensive relays, or required the user to change termination modules every time the interface standard has changed. Custom cables have been used LTC1545 U U W U APPLICATIONS INFORMATION LATCH 21 LTC1344A DCE/ DTE M2 22 23 M1 M0 (DATA) 24 1 CONNECTOR (DATA) M0 LTC1543 M1 M2 DCE/DTE DCE/DTE M2 M1 LTC1545 M0 D4ENB R4EN 11 12 13 NC 14 NC 14 CABLE VCC 13 12 11 15 10k 16 (DATA) 1545 F10 Figure 10: Single Port DCE V.35 Mode Selection in the Cable with the termination in the cable head or separate terminations are built on the board and a custom cable routes the signals to the appropriate termination. Switching the terminations with FETs is difficult because the FETs must remain off even though the signal voltage is beyond the supply voltage for the FET drivers or the power is off. The V.10 receiver configuration in the LTC1545 is shown in Figure 13. In V.10 mode switch S3 inside the LTC1545 is turned off. The noninverting input is disconnected inside the LTC1545 receiver and connected to ground.The cable termination is then the 30k input impedance to ground of the LTC1545 V.10 receiver. Using the LTC1344A along with the LTC1543/LTC1545 solves the cable termination switching problem. Via software control, the LTC1344A provides termination for the V.10 (RS423), V.11 (RS422), V.28 (RS232) and V.35 electrical protocols. V.11 (RS422) Interface V.10 (RS423) Interface A typical V.10 unbalanced interface is shown in Figure 11. A V.10 single-ended generator output A with ground C is connected to a differential receiver with inputs A' connected to A, and input C' connected to the signal return ground C. Usually, no cable termination is required for V.10 interfaces, but the receiver inputs must be compliant with the impedance curve shown in Figure 12. A typical V.11 balanced interface is shown in Figure 14. A V.11 differential generator with outputs A and B with ground C is connected to a differential receiver with ground C', inputs A' connected to A, B' connected to B. The V.11 interface has a differential termination at the receiver end that has a minimum value of 100. The termination resistor is optional in the V.11 specification, but for the high speed clock and data lines, the termination is required to prevent reflections from corrupting the data. The receiver inputs must also be compliant with the impedance curve shown in Figure 12. 9 LTC1545 U U W U APPLICATIONS INFORMATION BALANCED INTERCONNECTING CABLE GENERATOR GENERATOR LOAD CABLE TERMINATION C' C LOAD CABLE TERMINATION RECEIVER A' A BALANCED INTERCONNECTING CABLE 1545 F11 Figure 11. Typical V.10 Interface A A' B B' C C' RECEIVER 100 MIN 1545 F14 Figure 14. Typical V.11 Interface A' A IZ 3.25mA R1 51.5 LTC1344A R8 6k LTC1543 LTC1545 R5 20k R6 10k S1 S2 -10V -3V 3V 10V R3 124 R2 51.5 VZ RECEIVER S3 R4 20k B R7 10k B' GND C' 1545 F15 Figure 15. V.11 Receiver Configuration 1545 F12 -3.25mA Figure 12. V.10 Receiver Input Impedance In V.11 mode, all switches are off except S1 inside the LTC1344A which connects a 103 differential termination impedance to the cable as shown in Figure 15. V.28 (RS232) Interface A' A LTC1545 R8 6k R5 20k R6 10k S3 B' C' R4 20k B GND RECEIVER R7 10k 1545 F13 Figure 13. V.10 Receiver Configuration 10 A typical V.28 unbalanced interface is shown in Figure 16. A V.28 single-ended generator output A with ground C is connected to a single-ended receiver with input A' connected to A, ground C' connected via the signal return ground C. In V.28 mode, all switches are off except S3 inside the LTC1543/LTC1545 which connects a 6k (R8) impedance to ground in parallel with 20k (R5) plus 10k (R6) for a combined impedance of 5k as shown in Figure 17. The noninverting input is disconnected inside the LTC1543/ LTC1545 receiver and connected to a TTL level reference voltage for a 1.4V receiver trip point. LTC1545 U U W U APPLICATIONS INFORMATION BALANCED INTERCONNECTING CABLE GENERATOR LOAD CABLE TERMINATION RECEIVER A' A C' C 1545 F16 Figure 16. Typical V.28 Interface A' A R1 51.5 LTC1344A S1 R8 6k R3 124 S2 R2 51.5 R6 10k S3 R4 20k B In V.35 mode, both switches S1 and S2 inside the LTC1344A are on, connecting the T network impedance as shown in Figure 19. Both switches in the LTC1543 are off. The 30k input impedance of the receiver is placed in parallel with the T network termination, but does not affect the overall input impedance significantly. The generator differential impedance must be 50 to 150 and the impedance between shorted terminals (A and B) and ground C must be 150 15. For the generator termination, switches S1 and S2 are both on and the top side of the center resistor is brought out to a pin so it can be bypassed with an external capacitor to reduce common mode noise as shown in Figure 20. LTC1543 LTC1545 R5 20k V.35 interface requires a T or delta network termination at the receiver end and the generator end. The receiver differential impedance measured at the connector must be 100 10, and the impedance between shorted terminals (A' and B') and ground C' must be 150 15. RECEIVER R7 10k B' A' GND C' A 1545 F17 R1 51.5 Figure 17. V.28 Receiver Configuration S2 GENERATOR A 50 RECEIVER 125 125 50 50 R7 10k R4 20k B B' 1545 F19 GND C' A' RECEIVER S3 R3 124 R2 51.5 LOAD CABLE TERMINATION R8 6k R5 20k R6 10k S1 BALANCED INTERCONNECTING CABLE LTC1543 LTC1344A Figure 19. V.35 Receiver Configuration 50 B B' C C' A LTC1344A 51.5 1545 F18 Figure 18. Typical V.35 Interface V.35 DRIVER 124 S2 ON S1 ON 51.5 V.35 Interface B A typical V.35 balanced interface is shown in Figure 18. A V.35 differential generator with outputs A and B with ground C is connected to a differential receiver with ground C', inputs A' connected to A, B' connected to B. The C1 100pF C 1545 F20 Figure 20. V.35 Driver Using the LTC1344A 11 LTC1545 U U W U APPLICATIONS INFORMATION Any mismatch in the driver rise and fall times or skew in the driver propagation delays will force current through the center termination resistor to ground, causing a high frequency common mode spike on the A and B terminals. The common mode spike can cause EMI problems that are reduced by capacitor C1 which shunts much of the common mode energy to ground rather than down the cable. No-Cable Mode The no-cable mode (M0 = M1 = M2 = D4ENB = 1, R4EN = 0) is intended for the case when the cable is disconnected from the connector. The charge pump, bias circuitry, drivers and receivers are turned off, the driver outputs are forced into a high impedance state, and the supply current drops to less than 200A. Charge Pump The LTC1543 uses an internal capacitive charge pump to generate VDD and VEE as shown in Figure 21. A voltage doubler generates about 8V on VDD and a voltage inverter generates about - 7.5V for VEE. Four 1F surface mounted tantalum or ceramic capacitors are required for C1, C2, C3 and C4. The VEE capacitor C5 should be a minimum of 3.3F. All capacitors are 16V and should be placed as close as possible to the LTC1543 to reduce EMI. The turn-on time for the charge pump is 60ms. 3 C3 1F 2 C1 1F 1 4 5V VDD C2 + 28 + - 27 C1 C2 C2 1F The DCE/DTE pin acts as an enable for Driver 3/Receiver 1 in the LTC1543, and Driver 3/Receiver 1 in the LTC1545. The LTC1543/LTC1545 can be configured for either DTE or DCE operation in one of two ways: a dedicated DTE or DCE port with a connector of appropriate gender, or a port with one connector that can be configured for DTE or DCE operation by rerouting the signals to the LTC1543/LTC1545 using a dedicated DTE cable or dedicated DCE cable. A dedicated DTE port using a DB-25 male connector is shown in Figure 22. The interface mode is selected by logic outputs from the controller or from jumpers to either VCC or GND on the mode select pins. A dedicated DCE port using a DB-25 female connector is shown in Figure 23. A port with one DB-25 connector, can be configured for either DTE or DCE operation is shown in Figure 24. The configuration requires separate cables for proper signal routing in DTE or DCE operation. For example, in DTE mode, the TXD signal is routed to Pins 2 and 14 via Driver 1 in the LTC1543. In DCE mode, Driver 1 now routes the RXD signal to Pins 2 and 14. Compliance Testing A European standard EN 45001 test report is available for the LTC1343/LTC1545/LTC1344A chipset. A copy of the test report is available from LTC or TUV Telecom Services Inc. (formerly Detecon Inc.) The title of the report is: LTC1543 C1- VCC VEE GND 26 25 + C5 3.3F C4 1F 1545 F21 Figure 21. Charge Pump Receiver Fail-Safe All LTC1543/LTC1545 receivers feature fail-safe operation in all modes. If the receiver inputs are left floating or shorted together by a termination resistor, the receiver output will always be forced to a logic high. 12 DTE vs DCE Operation Test Report No. NET2/071601/98. The address of TUV Telecom Services Inc. is: TUV Telecom Services Inc. Suite 107 1775 Old Highway 8 St. Paul, MN 55112 USA Tel. +1 (612) 639-0775 Fax. +1 (612) 639-0873 LTC1545 U TYPICAL APPLICATIONS C6 C7 C8 100pF 100pF 100pF 3 8 11 12 13 LTC1344A VCC 5V 14 4 25 C5 1F LTC1543 5 TXD D1 6 SCTE D2 7 11 12 13 14 VCC 5V RTS DTR R2 10 RXD C10 1F R1 9 RXC C9 1F R3 CTS LL RI TM RL 14 22 24 21 11 20 15 19 12 18 17 17 9 16 3 15 16 1 VEE GND D1 D2 TXD A (103) TXD B SCTE A (113) SCTE B TXC A (114) TXC B RXC A (115) RXC B RXD A (104) RXD B SG SHIELD DB-25 MALE CONNECTOR 36 C11 1F 35 34 4 33 19 32 20 31 23 RTS A (105) RTS B DTR A (108) DTR B D3 6 R1 7 R2 8 R3 9 D4 10 R4 17 R5 18 14 2 23 DCE/DTE 4 13 24 M2 3 12 16 15 18 17 19 20 22 23 24 1 M1 1,19 VCC 2,20 VDD 11 9 10 7 LTC1545 DSR 5 4 6 7 M0 5 DCD VEE C12 1F D3 8 TXC 2 C4 3.3F M0 CHARGE PUMP 2 21 C2 1F 26 M1 27 LATCH M2 1 VCC DCE/DTE C1 1F 28 + C3 1F 3 C13 1F D5 M0 D4ENB M1 M2 R4EN 30 8 29 10 28 6 27 22 26 5 25 13 24 18 23 * 22 25 21 21 DCD A (109) DCD B DSR A (107) DSR B CTS A (106) CTS B LL (141) RI (125) TM (142) RL (140) 15 16 NC DCE/DTE M0 M1 M2 *OPTIONAL 1544 F22 Figure 22. Controller-Selectable Multiprotocol DTE Port with DB-25 Connector 13 LTC1545 U TYPICAL APPLICATIONS C6 C7 C8 100pF 100pF 100pF 3 8 11 12 13 LTC1344A VCC 5V 14 4 25 C5 1F LTC1543 5 RXD RXC D2 7 R2 10 TXD 11 12 13 NC VCC 5V C10 1F R1 9 SCTE C9 1F 14 R3 VEE GND D1 D2 R1 R2 R3 R4 17 R5 18 11 12 13 NC 14 9 20 15 19 12 18 24 17 11 16 2 15 14 RXC A (115) RXC B TXC A (114) TXC B SCTE A (113) SCTE B TXD A (103) TXD B SGND (102) SHIELD (101) 36 C11 1F 35 34 5 33 13 32 6 31 22 30 8 29 10 28 20 27 23 CTS A (106) CTS B DSR A (107) DSR B D5 M0 D4ENB M1 M2 R4EN DCD A (109) DCD B DTR A (108) DTR B 4 RTS A (105) 19 RTS B 24 * 23 18 22 21 21 25 RI (125) LL (141) RL (140) TM (142) 15 16 NC DCE/DTE M0 M1 M2 *OPTIONAL 1544 F23 Figure 23. Controller-Selectable DCE Port with DB-25 Connector 14 RXD B DB-25 FEMALE CONNECTOR 25 D4 10 RL 21 26 9 TM 17 RXD A (104) D3 8 LL 22 1 1,19 VCC 2,20 VDD 7 RI 16 7 LTC1545 RTS 3 23 DCE/DTE 6 DTR VCC M2 5 DCD 16 15 18 17 19 20 22 23 24 1 M1 4 DSR 9 10 M0 3 CTS 5 4 6 7 D3 8 TXC VEE C12 1F 24 D1 6 2 C4 3.3F M0 CHARGE PUMP 2 21 C2 1F M1 27 26 LATCH VCC M2 1 C13 1F DCE/DTE C1 1F 28 + C3 1F 3 LTC1545 U TYPICAL APPLICATIONS C6 C7 C8 100pF 100pF 100pF 3 8 11 12 13 LTC1344A VCC 5V 14 4 25 C5 1F LTC1543 5 DTE_TXD/DCE_RXD D1 6 DTE_SCTE/DCE_RXC D2 7 R1 9 DTE_RXC/DCE_SCTE R2 10 DTE_RXD/DCE_TXD 11 12 VEE C12 1F 5 4 6 7 9 10 16 15 18 17 19 20 22 23 24 1 24 2 23 14 22 24 21 11 R3 20 15 19 12 18 17 17 9 16 3 15 16 M0 7 M1 13 M2 14 DCE/DTE C10 1F DTE_RTS/DCE_CTS DTE_DTR/DCE_DSR VCC 5V C9 1F 1,19 VCC 2,20 VDD 3 1 VEE GND D1 4 D2 5 DTE_DSR/DCE_DTR DTE_CTS/DCE_RTS DTE_LL/DCE_RI DTE_RI/DCE_LL DTE_TM/DCE_RL DTE_RL/DCE_TM 6 R1 7 R2 8 R3 9 D4 10 R4 17 R5 18 11 12 13 14 DCE RXD A TXD B RXD B SCTE A RXC A SCTE B RXC B TXC A TXC A TXC B TXC B RXC A SCTE A RXC B SCTE B RXD A TXD A RXD B TXD B SG SHIELD DB-25 CONNECTOR 36 C11 1F 35 34 4 33 19 32 20 31 23 RTS A CTS A RTS B CTS B DTR A DSR A DTR B DSR B DCD A DCD A D3 LTC1545 DTE_DCD/DCE_DCD DTE TXD A D3 8 DTE_TXC/DCE_TXC 2 C4 3.3F M0 CHARGE PUMP 2 21 C2 1F M1 27 26 M2 1 LATCH VCC DCE/DTE C1 1F 28 + C3 1F 3 C13 1F D5 M0 D4ENB M1 M2 R4EN 30 8 29 10 28 6 27 22 26 5 25 13 24 18 23 * 22 25 21 21 DCD B DCD B DSR A DTR A DSR B DTR B CTS A RTS A CTS B RTS B LL RI RI LL TM RL RL TM 15 16 NC DCE/DTE DCE/DTE M0 M1 M2 *OPTIONAL 1544 F24 Figure 24. Controller-Selectable Multiprotocol DTE/DCE Port with DB-25 Connector 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 representation that the interconnection of its circuits as described herein will not infringe on existing patent rights. 15 LTC1545 U PACKAGE DESCRIPTION Dimensions in inches (millimeters) unless otherwise noted. G Package 36-Lead Plastic SSOP (0.209) (LTC DWG # 05-08-1640) 12.67 - 12.93* (0.499 - 0.509) 36 35 34 33 32 31 30 29 28 27 26 25 24 23 22 21 20 19 7.65 - 7.90 (0.301 - 0.311) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 5.20 - 5.38** (0.205 - 0.212) 1.73 - 1.99 (0.068 - 0.078) 0 - 8 0.65 (0.0256) BSC 0.55 - 0.95 (0.022 - 0.037) 0.13 - 0.22 (0.005 - 0.009) NOTE: DIMENSIONS ARE IN MILLIMETERS *DIMENSIONS DO NOT INCLUDE MOLD FLASH. MOLD FLASH SHALL NOT EXCEED 0.152mm (0.006") PER SIDE **DIMENSIONS DO NOT INCLUDE INTERLEAD FLASH. INTERLEAD FLASH SHALL NOT EXCEED 0.254mm (0.010") PER SIDE 0.05 - 0.21 (0.002 - 0.008) 0.25 - 0.38 (0.010 - 0.015) G36 SSOP 1098 RELATED PARTS PART NUMBER DESCRIPTION LTC1321 Dual RS232/RS485 Transceiver Two RS232 Driver/Receiver Pairs or Two RS485 Driver/Receiver Pairs LTC1322 Dual RS232/RS485 Transceiver Four RS232 Driver/Receiver Pairs or Two RS485 Driver/Receiver Pairs LTC1334 Single 5V RS232/RS485 Multiprotocol Transceiver Two RS232 Driver/Receiver Pairs or Four RS232 Driver/Receiver Pairs LTC1335 Dual RS232/RS485 Transceiver Four RS232 Driver/Receiver Pairs or Two RS485 Driver/Receiver Pairs LTC1343 Software-Selectable Multiprotocol Transceiver 4-Driver/4-Receiver for Data and Clock Signals LTC1344A Software-Selectable Cable Terminator Perfect for Terminating the LTC1543 LTC1345 Single Supply V.35 Transceiver 3-Driver/3-Receiver for Data and Clock Signals LTC1346A Dual Supply V.35 Transceiver 3-Driver/3-Receiver for Data and Clock Signals LTC1543 Software-Selectable Multiprotocol Transceiver Companion to LTC1544/LTC1545 for Data and Clock Signals LTC1544 Software-Selectable Multiprotocol Transceiver 4-Driver/4-Receiver for Control Signals LTC1387 Single 5V RS232/RS485 Multiprotocol Transceiver Two RS232 Driver/Receiver Pairs or One RS485 Driver/Receiver Pair 16 COMMENTS Linear Technology Corporation sn1545 1545fas LT/TP 1199 2K REV A * PRINTED IN 1630 McCarthy Blvd., Milpitas, CA 95035-7417 USA (408)432-1900 FAX: (408) 434-0507 www.linear-tech.com LINEAR TECHNOLOGY CORPORATION 1998