LTC1543 Software-Selectable Multiprotocol Transceiver U FEATURES DESCRIPTIO The LTC(R)1543 is a 3-driver/3-receiver multiprotocol transceiver that operates from a single 5V supply. The LTC1543 and LTC1544 form the core of a complete softwareselectable 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. 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. NET2/102201/97) TBR2 Compliant (Test Report No. CTR2/022701/98) Software-Selectable Cable Termination Using the LTC1344A Complete DTE or DCE Port with LTC1544, LTC1344A Operates from Single 5V Supply The LTC1543 runs from a single 5V supply using an internal charge pump that requires only five space-saving surface mounted capacitors. The part is available in a 28-lead SSOP surface mount package. 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 LL CTS DSR DCD DTR RTS RXD TXC RXC D3 R4 R2 R3 TXD D2 D1 LTC1543 LTC1544 D4 SCTE D2 D3 D1 R3 R1 R2 R1 LTC1344A 18 13 5 22 6 10 8 23 20 19 4 1 7 16 3 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 CTS B LL A (141) DB-25 CONNECTOR 9 1543 TA01 sn1534 1543fas 1 LTC1543 W W W AXI U U ABSOLUTE RATI GS U U W PACKAGE/ORDER I FOR ATIO (Note 1) Supply Voltage ....................................................... 6.5V 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) Logic Pins .............................. - 0.3V to (VCC + 0.3V) VEE ........................................................ - 10V to 0.3V VDD ....................................................... - 0.3V to 10V Short-Circuit Duration Transmitter Output ..................................... Indefinite Receiver Output .......................................... Indefinite VEE .................................................................. 30 sec Operating Temperature Range LTC1543C .............................................. 0C to 70C LTC1543I ........................................... - 40C to 85C Storage Temperature Range ................ - 65C to 150C Lead Temperature (Soldering, 10 sec)................. 300C ELECTRICAL CHARACTERISTICS ORDER PART NUMBER TOP VIEW C1- 1 C1+ 2 VDD 3 VCC 4 D1 5 D2 6 28 C2 + 27 C2 - CHARGE PUMP 26 VEE LTC1543CG LTC1543IG 25 GND 24 D1 A D1 D3 7 R1 8 R2 9 23 D1 B D2 22 D2 A 21 D2 B D3 20 D3/R1 A R3 10 19 D3/R1 B R1 18 R2 A M0 11 R2 M1 12 M2 13 17 R2 B 16 R3 A R3 15 R3 B DCE/DTE 14 G PACKAGE 28-LEAD PLASTIC SSOP TJMAX = 150C, JA = 90C/ W Consult LTC Marketing for parts specified with wider operating temperature ranges. The denotes specifications which apply over the full operating tempera- ture range. VCC = 5V (Notes 2, 3) SYMBOL PARAMETER CONDITIONS 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.35 Mode, No Load V.35 Mode, Full Load V.28 Mode, No Load V.28 Mode, Full Load No-Cable Mode MIN TYP MAX UNITS Supplies ICC PD Internal Power Dissipation (DCE Mode) RS530, RS530-A, X.21 Modes, Full Load V.35 Mode, Full Load V.28 Mode, Full Load V+ Positive Charge Pump Output Voltage Any Mode, No Load V.28 Mode, with Load V.28 Mode, with Load, IDD = 10mA V- Negative Charge Pump Output Voltage V.28, V.35 Modes, No Load V.28 Mode, Full Load V.35 Mode, Full Load RS530, RS530-A, X.21 Modes, Full Load fOSC Charge Pump Oscillator Frequency tr Supply Rise Time 13 100 20 126 20 40 120 8.0 8.0 - 8.0 - 5.5 - 4.5 No-Cable Mode or Power-Up to Turn On 130 170 75 500 mA mA mA mA mA mA A 230 600 140 mW mW mW 9.4 8.7 6.5 V V V - 9.6 - 8.5 - 6.7 - 5.7 V V V V 150 kHz 2 ms Logic Inputs and Outputs VIH Logic Input High Voltage VIL Logic Input Low Voltage 2 V 0.8 V sn1534 1543fas 2 LTC1543 ELECTRICAL CHARACTERISTICS The denotes specifications which apply over the full operating tempera- ture range. VCC = 5V (Notes 2, 3) SYMBOL PARAMETER CONDITIONS IIN Logic Input Current D1, D2, D3 M0, M1, M2, DCE = GND (LTC1543C) M0, M1, M2, DCE = GND (LTC1543I) M0, M1, M2, DCE = VCC MIN 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 VODO Open Circuit Differential Output Voltage RL = 1.95k (Figure 1) VODL Loaded Differential Output Voltage RL = 50 (Figure 1) RL = 50 (Figure 1) TYP MAX UNITS - 100 - 120 - 50 - 50 10 - 30 - 30 10 A A A A 3 4.5 0.3 - 50 V 0.8 V 50 mA 1 A V.11 Driver 0.5VODO 2 5 V 0.67VODO V 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 (Figures 2, 6) (LTC1543C) (Figures 2, 6) (LTC1543I) t PLH Input to Output (Figures 2, 6) (LTC1543C) (Figures 2, 6) (LTC1543I) 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 (Figures 2, 6) (LTC1543C) (Figures 2, 6) (LTC1543I) 20 20 40 40 65 75 ns ns Input to Output Difference, tPLH - tPHL (Figures 2, 6) (LTC1543C) (Figures 2, 6) (LTC1543I) 0 0 3 3 12 17 ns ns Output to Output Skew (Figures 2, 6) 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, 7) t PLH Input to Output (Figures 2, 7) (LTC1543C) (Figures 2, 7) (LTC1543I) 50 50 80 90 ns ns t PHL Input to Output (Figures 2, 7) (LTC1543C) (Figures 2, 7) (LTC1543I) 50 50 80 90 ns ns t Input to Output Difference, tPLH - tPHL (Figures 2, 7) (LTC1543C) (Figures 2, 7) (LTC1543I) 0 0 4 4 16 21 ns ns V V - 0.2 15 15 0.2 V 40 mV 0.66 mA 30 k 15 ns V.35 Driver VOD Differential Output Voltage Open Circuit With Load, - 4V VCM 4V (Figure 3) 0.44 0.55 10.00 0.66 IOH Transmitter Output High Current VA, B = 0V - 13 - 11 - 9.0 mA IOL Transmitter Output Low Current VA, B = 0V 9.0 11 13 mA sn1534 1543fas 3 LTC1543 ELECTRICAL CHARACTERISTICS The denotes specifications which apply over the full operating tempera- ture range. VCC = 5V (Notes 2, 3) SYMBOL PARAMETER CONDITIONS MIN IOZ Transmitter Output Leakage Current - 0.25V VA, B 0.25V tr, tf Rise or Fall Time (Figures 3, 6) t PLH Input to Output (Figures 3, 6) (LTC1543C) (Figures 3, 6) (LTC1543I) 20 20 35 35 65 75 ns ns t PHL Input to Output (Figures 3, 6) (LTC1543C) (Figures 3, 6) (LTC1543I) 20 20 35 35 65 75 ns ns t Input to Output Difference, tPLH - tPHL (Figures 3, 6) (LTC1543C) (Figures 3, 6) (LTC1543I) 0 0 4 4 16 21 ns ns t SKEW Output to Output Skew (Figures 3, 6) TYP MAX UNITS 1 100 A 5 ns 4 ns V.35 Receiver VTH Differential Receiver Input Threshold Voltage - 2V (VA + VB)/2 2V (Figure 3) VTH Receiver Input Hysteresis - 2V (VA + VB)/2 2V (Figure 3) IIN Receiver Input Current (A, B) - 10V VA,B 10V RIN Receiver Input Impedance - 10V VA,B 10V t r, t f Rise or Fall Time (Figures 3, 7) tPLH Input to Output (Figures 3, 7) (LTC1543C) (Figures 3, 7) (LTC1543I) 50 50 80 90 ns ns tPHL Input to Output (Figures 3, 7) (LTC1543C) (Figures 3, 7) (LTC1543I) 50 50 80 90 ns ns t Input to Output Difference, tPLH - tPHL (Figures 3, 7) (LTC1543C) (Figures 3, 7) (LTC1543I) 0 0 4 4 16 21 ns ns VO Output Voltage Open Circuit RL = 3k (Figure 4) 5 8.5 10 V V ISS Short-Circuit Current VOUT = GND 150 mA IOZ Output Leakage Current - 0.25V VO 0.25V, Power Off or No-Cable Mode or Driver Disabled 1 100 A SR Slew Rate RL = 3k, CL = 2500pF (Figures 4, 8) 30 V/s t PLH Input to Output RL = 3k, CL = 2500pF (Figures 4, 8) 1.5 2.5 s t PHL Input to Output RL = 3k, CL = 2500pF (Figures 4, 8) 1.5 3 s 1.2 0.8 V - 0.2 0.2 15 15 V 40 mV 0.66 mA 30 k 15 ns V.28 Driver 4 V.28 Receiver VTHL Input Low Threshold Voltage VTLH Input High Threshold Voltage 2 1.2 VTH Receiver Input Hysteresis 0 0.05 0.3 RIN Receiver Input Impedance - 15V VA 15V 3 5 7 t r, tf tPLH Rise or Fall Time (Figures 5, 9) Input to Output (Figures 5, 9) 60 100 ns tPHL Input to Output (Figures 5, 9) 160 250 ns Note 1: Absolute Maximum Ratings are those beyond which the safety 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. V V k 15 ns Note 3: All typicals are given for VCC = 5V, C1 = C2 = CVCC = 1F, CVDD = CVEE = 3.3F tantalum capacitors and TA = 25C. sn1534 1543fas 4 LTC1543 U U U PI FU CTIO S C1 - (Pin 1): Capacitor C1 Negative Terminal. Connect a 1F capacitor between C1+ and C1-. R3 B (Pin 15): Receiver 3 Noninverting Input with Pull-Up to VCC. C1 + (Pin 2): Capacitor C1 Positive Terminal. Connect a 1F capacitor between C1 + and C1 -. R3 A (Pin 16): Receiver 3 Inverting Input. VDD (Pin 3): Generated Positive Supply Voltage for V.28. Connect a 1F capacitor to ground. R2 A (Pin 18): Receiver 2 Inverting Input. VCC (Pin 4): Positive Supply Voltage Input. 4.75V VCC 5.25V. Bypass with a 1F capacitor to ground. D1 (Pin 5): TTL Level Driver 1 Input. D2 (Pin 6): TTL Level Driver 2 Input. R2 B (Pin 17): Receiver 2 Noninverting Input. D3/R1 B (Pin 19): Receiver 1 Noninverting Input and Driver 3 Noninverting Output. D3/R1 A (Pin 20): Receiver 1 Inverting Input and Driver 3 Inverting Output. D2 B (Pin 21): Driver 2 Noninverting Output. D3 (Pin 7): TTL Level Driver 3 Input. D2 A (Pin 22): Driver 2 Inverting Output. R1 (Pin 8): CMOS Level Receiver 1 Output. R2 (Pin 9): CMOS Level Receiver 2 Output. R3 (Pin 10): CMOS Level Receiver 3 Output. D1 B (Pin 23): Driver 1 Noninverting Output. D1 A (Pin 24): Driver 1 Inverting Output. GND (Pin 25): Ground. M0 (Pin 11): TTL Level Mode Select Input 0 with Pull-Up to VCC. VEE (Pin 26): Negative Supply Voltage. Connect a 3.3F capacitor to GND. M1 (Pin 12): TTL Level Mode Select Input 1 with Pull-Up to VCC. C2 - (Pin 27): Capacitor C2 Negative Terminal. Connect a 1F capacitor between C2 + and C2 -. M2 (Pin 13): TTL Level Mode Select Input 2 with Pull-Up to VCC. C2 + (Pin 28): Capacitor C2 Positive Terminal. Connect a 1F capacitor between C2 + and C2 - . DCE/DTE (Pin 14): TTL Level Mode Select Input with PullUp to VCC. TEST CIRCUITS A RL 50 B VOD A RL 50 B RL 100 CL 100pF B CL 100pF A R VOC 1543 F01 Figure 1. V.11 Driver Test Circuit 15pF 1543 F02 Figure 2. V.11 Driver/Receiver AC Test Circuit sn1534 1543fas 5 LTC1543 TEST CIRCUITS 50 D B VCM 125 50 B 125 R VOD A A 50 15pF 50 1543 F03 Figure 3. V.35 Driver/Receiver Test Circuit D A D A A R RL CL 15pF 1543 F04 1543 F04 Figure 5. V.10/V.28 Receiver Test Circuit Figure 4. V.10/V.28 Driver Test Circuit U W ODE SELECTIO LTC1543 MODE NAME M2 M1 M0 DCE/DTE D1 D2 D3 R1 R2 R3 Not Used (Default V.11) 0 0 0 0 V.11 V.11 Z V.11 V.11 V.11 RS530A 0 0 1 0 V.11 V.11 Z V.11 V.11 V.11 RS530 0 1 0 0 V.11 V.11 Z V.11 V.11 V.11 X.21 0 1 1 0 V.11 V.11 Z V.11 V.11 V.11 V.35 1 0 0 0 V.35 V.35 Z V.35 V.35 V.35 RS449/V.36 1 0 1 0 V.11 V.11 Z V.11 V.11 V.11 V.28/RS232 1 1 0 0 V.28 V.28 Z V.28 V.28 V.28 No Cable 1 1 1 0 Z Z Z Z Z Z Not Used (Default V.11) 0 0 0 1 V.11 V.11 V.11 Z V.11 V.11 RS530A 0 0 1 1 V.11 V.11 V.11 Z V.11 V.11 RS530 0 1 0 1 V.11 V.11 V.11 Z V.11 V.11 X.21 0 1 1 1 V.11 V.11 V.11 Z V.11 V.11 V.35 1 0 0 1 V.35 V.35 V.35 Z V.35 V.35 RS449/V.36 1 0 1 1 V.11 V.11 V.11 Z V.11 V.11 V.28/RS232 1 1 0 1 V.28 V.28 V.28 Z V.28 V.28 No Cable 1 1 1 1 Z Z Z Z Z Z sn1534 1543fas 6 LTC1543 U W W SWITCHI G TI E WAVEFOR S 5V f = 1MHz : t r 10ns : t f 10ns 1.5V D 0V 1.5V t PHL t PLH VO B-A -VO 90% 50% 90% VDIFF = V(A) - V(B) 10% 1/2 VO tr 50% 10% tf A VO B t SKEW t SKEW 1543 F06 Figure 6. V.11, V.35 Driver Propagation Delays VOD2 B-A -VOD2 f = 1MHz : t r 10ns : t f 10ns 0V INPUT 0V t PHL t PLH VOH R VOL OUTPUT 1.5V 1.5V 1543 F07 Figure 7. V.11, V.35 Receiver Propagation Delays 3V 1.5V 1.5V D 0V t PHL VO t PLH 3V 3V 0V A 0V -3V -VO 1543 F08 -3V tf tr Figure 8. V.10, V.28 Driver Propagation Delays VIH 1.7V 1.3V A VIL VOH R VOL t PHL t PLH 2.4V 0.8V 1543 F09 Figure 9. V.10, V.28 Receiver Propagation Delays sn1534 1543fas 7 LTC1543 U W U U APPLICATIO S I FOR ATIO Overview The LTC1543/LTC1544 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. A complete DCE-to-DTE interface operating in EIA530 mode is shown in Figure 10. The LTC1543 of each port is used to generate the clock and data signals. The LTC1544 is used to generate the control signals along with LL (Local Loopback).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. Mode Selection The interface protocol is selected using the mode select pins M0, M1 and M2 (see the Mode Selection table). 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 11. The internal pull-up current sources will ensure a binary 1 when a pin is left unconnected and that the LTC1543/ LTC1544 and the LTC1344A enter the no-cable mode when the cable is removed. In the no-cable mode the LTC1543/LTC1544 supply current drops to less than 200A and all LTC1543/LTC1544 driver outputs and LTC1344A resistive terminations are forced into a high impedance state. 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 requiring the user to change termination modules every time the interface standard has changed. Custom cables have been used 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. Using the LTC1344A along with the LTC1543/LTC1544 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.10 (RS423) Interface A typical V.10 unbalanced interface is shown in Figure 12. 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 13. The V.10 receiver configuration in the LTC1544 is shown in Figure 14. In V.10 mode switch S3 inside the LTC1544 is turned off.The noninverting input is disconnected inside the LTC1544 receiver and connected to ground. The cable termination is then the 30k input impedance to ground of the LTC1544 V.10 receiver. sn1534 1543fas 8 LTC1543 U W U U APPLICATIO S I FOR ATIO 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 LTC1544 LTC1544 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 LL D4 R4 R4 LL D4 1543 F10 Figure 10. Complete Multiprotocol Interface in EIA530 Mode sn1534 1543fas 9 LTC1543 U W U U APPLICATIO S I FOR ATIO LATCH 21 LTC1344A DCE/ DTE M2 22 M1 M0 (DATA) 23 24 1 CONNECTOR (DATA) M0 LTC1543 M1 M2 DCE/DTE 11 12 13 NC 14 NC CABLE LTC1544 DCE/DTE M2 M1 M0 14 13 12 11 1543 F11 (DATA) Figure 11. Single Port DCE V.35 Mode Selection in the Cable BALANCED INTERCONNECTING CABLE GENERATOR LOAD CABLE TERMINATION A A' C C' RECEIVER 1543 F12 Figure 12. Typical V.10 Interface sn1534 1543fas 10 LTC1543 U W U U APPLICATIO S I FOR ATIO IZ 3.25mA A' A LTC1544 R8 6k -10V R5 20k R6 10k -3V S3 VZ 3V RECEIVER 10V B B' C' 1543 F13 R7 10k R4 20k GND 1543 F14 -3.25mA Figure 14. V.10 Receiver Configuration Figure 13. V.10 Receiver Input Impedance GENERATOR V.11 (RS422) Interface A typical V.11 balanced interface is shown in Figure 15. 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 13. BALANCED INTERCONNECTING CABLE LOAD CABLE TERMINATION A A' B B' C C' RECEIVER 100 MIN 1543 F15 Figure 15. Typical V.11 Interface A' A 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 16. R1 51.5 LTC1344A R8 6k LTC1543 LTC1544 R5 20k R6 10k S1 S2 R2 51.5 RECEIVER S3 R3 124 R4 20k B R7 10k B' C' GND 1543 F16 Figure 16. V.11 Receiver Configuration sn1534 1543fas 11 LTC1543 U W U U APPLICATIO S I FOR ATIO V.28 (RS232) Interface V.35 Interface A typical V.28 unbalanced interface is shown in Figure 17. 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. A typical V.35 balanced interface is shown in Figure 19. 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 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. In V.28 mode all switches are off except S3 inside the LTC1543/LTC1544 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 18. The noninverting input is disconnected inside the LTC1543/ LTC1544 receiver and connected to a TTL level reference voltage for a 1.4V receiver trip point. BALANCED INTERCONNECTING CABLE GENERATOR In V.35 mode, both switches S1 and S2 inside the LTC1344A are on, connecting the T network impedance as shown in Figure 20. The switch in the LTC1543 is off. The 30k input GENERATOR LOAD CABLE TERMINATION BALANCED INTERCONNECTING CABLE RECEIVER 50 C' C 125 125 50 1543 F17 RECEIVER A' A A' A LOAD CABLE TERMINATION 50 50 B B' C C' Figure 17. Typical V.28 Interface 1543 F19 Figure 19. Typical V.35 Interface A' A R1 51.5 S1 S2 R2 51.5 LTC1344A R8 6k A' A R6 10k S3 R3 124 LTC1543 LTC1544 R5 20k RECEIVER R1 51.5 LTC1543 R8 6k R5 20k R6 10k R4 20k B S1 R7 10k S2 R2 51.5 B' C' LTC1344A GND 1543 F18 RECEIVER S3 R3 124 R4 20k B R7 10k B' Figure 18. V.28 Receiver Configuration C' GND 1543 F20 Figure 20. V.35 Receiver Configuration sn1534 1543fas 12 LTC1543 U W U U APPLICATIO S I FOR ATIO 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 21. 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 = 1) 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 22. 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. Receiver Fail-Safe A LTC1344A V.35 DRIVER 124 51.5 S2 ON S1 ON All LTC1543/LTC1544 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. 51.5 3 B C1 100pF C3 1F C 2 C1 1F 1 1543 F21 Figure 21. V.35 Driver Using the LTC1344A 4 5V VDD C2 + 28 C1+ C2 - 27 C2 1F LTC1543 C1- VCC VEE GND 26 25 + C5 3.3F C4 1F 1543 F22 Figure 22. Charge Pump sn1534 1543fas 13 LTC1543 U W U U APPLICATIO S I FOR ATIO DTE vs DCE Operation The DCE/DTE pin acts as an enable for Driver 3/Receiver 1 in the LTC1543, and Driver 3/Receiver 1 and Driver 4/ Receiver 4 in the LTC1544. The INVERT pin in the LTC1544 allows the Driver 4/Receiver 4 enable to be high or low true polarity. The LTC1543/LTC1544 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/LTC1544 using a dedicated DTE cable or dedicated DCE cable. A dedicated DTE port using a DB-25 male connector is shown in Figure 23. 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 24. A port with one DB-25 connector, but can be configured for either DTE or DCE operation is shown in Figure 25. 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. Multiprotocol Interface with RL, LL, TM and a DB-25 Connector If the RL, LL and TM signals are implemented, there are not enough drivers and receivers available in the LTC1543/ LTC1544. In Figure 26, the required control signals are handled by the LTC1544 but the clock/data signals use the LTC1343. The LTC1343 has an additional single-ended driver/receiver pair that can handle two more optional control signals such as TM and LL. Cable-Selectable Multiprotocol Interface A cable-selectable multiprotocol DTE/DCE interface is shown in Figure 27. The select lines M0, M1 and DCE/DTE are brought out to the connector. The mode is selected by the cable by wiring M0 (connector Pin 18) and M1 (connector Pin 21) and DCE/DTE (connector Pin 25) to ground (connector Pin 7) or letting them float. If M0, M1 or DCE/ DTE is floating, internal pull-up current sources will pull the signals to VCC. The select bit M2 is hard wired to VCC. When the cable is pulled out, the interface will go into the no-cable mode. Compliance Testing A European standard EN 45001 test report is available for the LTC1543/LTC1544/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: Test Report No. NET2/102201/97. The address of TUV Telecom Services Inc. is: TUV Telecom Services Inc. Type Approval Division 1775 Old Highway 8, Ste 107 St. Paul, MN 55112 USA Tel. +1 (612) 639-0775 Fax. +1 (612) 639-0873 sn1534 1543fas 14 LTC1543 U TYPICAL APPLICATIO S C6 C7 C8 100pF 100pF 100pF 3 8 11 12 13 LTC1344A VCC 5V 14 CHARGE PUMP 2 4 25 C5 1F LTC1543 5 TXD D1 6 SCTE D2 7 11 12 13 14 C9 1F RTS DTR R2 10 RXD C10 1F R1 9 RXC R3 CTS LL 24 2 23 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 28 C11 1F 27 26 4 25 19 24 20 23 23 RTS A (105) RTS B DTR A (108) DTR B D3 6 R1 7 R2 8 R3 10 R4 9 14 16 15 18 17 19 20 22 23 24 1 DCE/DTE 4 13 9 10 M2 3 12 5 4 6 7 M1 VCC 1 VCC 2 VDD 11 VEE C12 1F 7 LTC1544 DSR 2 C4 3.3F M0 5 DCD C2 1F D3 8 TXC 21 M0 27 26 M1 1 LATCH M2 28 VCC DCE/DTE C1 1F 3 + C3 1F C13 1F 22 8 21 10 20 6 19 22 18 5 17 13 16 18 DCD A (109) DCD B DSR A (107) DSR B CTS A (106) CTS B LL A (141) D4 M0 INVERT 15 NC M1 M2 DCE/DTE M2 M1 M0 1543 F23 Figure 23. Controller-Selectable Multiprotocol DTE Port with DB-25 Connector sn1534 1543fas 15 LTC1543 U TYPICAL APPLICATIO S 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 C10 1F R1 9 SCTE 14 5 4 6 7 9 10 16 15 18 17 19 20 22 23 24 1 VCC 3 23 16 22 17 21 9 R3 20 15 19 12 18 24 17 11 16 2 15 14 M0 7 M1 M2 1 DCE/DTE 1 VCC 2 VDD 3 CTS VEE GND D1 4 DSR D2 5 LTC1544 R1 7 DTR R2 8 RTS R3 10 LL R4 9 11 12 13 NC 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) 28 C11 1F 27 26 5 25 13 24 6 23 22 CTS A (106) CTS B DSR A (107) DSR B D3 6 DCD RXD B DB-25 FEMALE CONNECTOR VCC C9 1F RXD A (104) D3 8 TXC VEE C12 1F 24 D1 6 2 C4 3.3F M0 CHARGE PUMP 2 21 C2 1F M1 27 26 LATCH M2 1 VCC DCE/DTE C1 1F 28 + C3 1F 3 C13 1F 22 8 21 10 20 20 19 23 18 4 17 19 16 18 DCD A (109) DCD B DTR A (108) DTR B RTS A (105) RTS B LL A (141) D4 M0 INVERT 15 NC M1 M2 DCE/DTE M2 M1 M0 1543 F24 Figure 24. Controller-Selectable DCE Port with DB-25 Connector sn1534 1543fas 16 LTC1543 U TYPICAL APPLICATIO S 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 S R1 S 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 C9 1F 1 1 VCC 2 VDD 3 VEE GND D1 4 D2 DTE_CTS/DCE_RTS DTE_LL/DCE_LL 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 6 R1 7 R2 8 R3 10 R4 9 11 12 13 14 28 C11 1F 27 26 4 25 19 24 20 23 23 RTS A CTS A RTS B CTS B DTR A DSR A DTR B DSR B DCD A DCD A D3 LTC1544 DTE_DSR/DCE_DTR DCE RXD A VCC 5 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 LATCH M2 1 VCC DCE/DTE C1 1F 28 + C3 1F 3 C13 1F 22 8 21 10 20 6 19 22 18 5 17 13 16 18 DCD B DCD B DSR A DTR A DSR B DTR B CTS A RTS A CTS B RTS B LL A LL A D4 M0 INVERT 15 NC M1 M2 DCE/DTE DCE/DTE M2 M1 M0 1543 F25 Figure 25. Controller-Selectable Multiprotocol DTE/DCE Port with DB-25 Connector sn1534 1543fas 17 LTC1543 U TYPICAL APPLICATIO S C6 C7 C8 100pF 100pF 100pF 3 8 11 12 13 LTC1344A VCC 5V 14 44 C5 1F 5 4 6 7 9 10 16 15 18 17 19 20 22 23 24 1 LTC1343 D1 D2 7 DTE_SCTE/DCE_RXC VEE C12 1F 8 6 DTE_TXD/DCE_RXD C4 3.3F M0 41 5 DTE_LL/DCE_TM 2 42 CHARGE PUMP 21 C2 1F 43 4 3 LATCH M1 C1 1F VCC M2 2 + C3 1F C13 1F DCE/DTE 1 D3 39 18 38 2 37 14 36 24 35 11 DTE DCE LL A TM A TXD A RXD A TXD B RXD B SCTE A RXC A SCTE B RXC B TXC A TXC A 34 9 DTE_TXC/DCE_TXC R1 14 DTE_RXC/DCE_SCTE R2 15 DTE_RXD/DCE_TXD R3 16 DTE_TM/DCE_LL 20 22 11 25 R1 100k 33 D4 10 12 13 R4 CTRL DCE LATCH M2 INVERT M1 423SET M0 GND EC DTE_RTS/DCE_CTS DTE_DTR/DCE_DSR LB DTE_CTS/DCE_RTS DTE_RL/DCE_RL C9 1F VCC 1 VCC 2 VDD 3 VEE GND D1 4 D2 17 29 9 28 3 27 16 26 25 21 7 19 1 18 TXC B RXC A SCTE A RXC B SCTE B RXD A TXD A RXD B TXD B TM A LL A SG SHIELD 17 24 6 R1 7 R2 8 R3 10 11 12 13 14 28 C11 1F 27 26 4 25 19 24 20 23 23 RTS A CTS A RTS B CTS B DTR A DSR A DTR B DSR B DCD A DCD A D3 R4 9 DCE/DTE M2 M1 M0 30 TXC B DB-25 CONNECTOR LTC1544 DTE_DSR/DCE_DTR 12 23 5 DTE_DCD/DCE_DCD 15 31 VCC 40 LB C10 1F 32 22 8 21 10 20 6 19 22 18 5 17 13 16 21 DCD B DCD B DSR A DTR A DSR B DTR B CTS A RTS A CTS B RTS B RL A RL A D4 M0 INVERT 15 NC M1 M2 DCE/DTE 1543 F26 Figure 26. Controller-Selectable Multiprotocol DTE/DCE Port with RL, LL, TM and DB-25 Connector sn1534 1543fas 18 LTC1543 U TYPICAL APPLICATIO S 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 D2 7 R1 9 DTE_RXC/DCE_SCTE R2 10 DTE_RXD/DCE_TXD 11 12 NC 13 14 5 4 6 7 9 10 16 15 18 17 19 20 22 23 24 1 VCC 2 23 14 22 24 21 11 DTE DCE TXD A 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 D3 8 DTE_TXC/DCE_TXC VEE C12 1F 24 D1 6 DTE_SCTE/DCE_RXC 2 C4 3.3F M0 CHARGE PUMP 2 21 C2 1F M1 27 26 LATCH M2 1 VCC DCE/DTE C1 1F 28 + C3 1F 3 C13 1F R3 20 15 19 12 18 17 17 9 16 3 15 16 M0 7 M1 M2 1 DCE/DTE SG SHIELD DB-25 CONNECTOR C10 1F C9 1F VCC 1 VCC 2 VDD VEE GND 25 DCE/DTE 21 M1 18 M0 4 RTS A 19 RTS B 20 DTR A 23 DTR B 28 C11 1F 27 26 3 DTE_RTS/DCE_CTS D1 24 4 DTE_DTR/DCE_DSR D2 5 LTC1544 R1 7 DTE_DSR/DCE_DTR R2 8 DTE_CTS/DCE_RTS R3 10 R4 9 11 12 NC 13 14 23 CTS A CTS B DSR A DSR B D3 6 DTE_DCD/DCE_DCD 25 22 8 21 10 20 6 19 22 18 5 17 13 CABLE WIRING FOR MODE SELECTION MODE V.35 RS449, V.36 RS232 M0 M1 DCE/DTE INVERT DCD A DCD B DCD B DSR A DTR A DSR B DTR B CTS A RTS A CTS B RTS B 16 D4 M2 DCD A 15 PIN 18 PIN 7 NC PIN 7 PIN 21 PIN 7 PIN 7 NC CABLE WIRING FOR DTE/DCE SELECTION MODE PIN 25 DTE PIN 7 DCE NC NC 1543/44 F27 Figure 27. Cable-Selectable Multiprotocol DTE/DCE Port with DB-25 Connector sn1534 1543fas 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. 19 LTC1543 U PACKAGE DESCRIPTIO Dimensions in inches (millimeters) unless otherwise noted. G Package 28-Lead Plastic SSOP (0.209) (LTC DWG # 05-08-1640) 0.397 - 0.407* (10.07 - 10.33) 28 27 26 25 24 23 22 21 20 19 18 17 16 15 0.301 - 0.311 (7.65 - 7.90) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 0.205 - 0.212** (5.20 - 5.38) 0.068 - 0.078 (1.73 - 1.99) 0 - 8 0.005 - 0.009 (0.13 - 0.22) 0.0256 (0.65) BSC 0.022 - 0.037 (0.55 - 0.95) *DIMENSIONS DO NOT INCLUDE MOLD FLASH. MOLD FLASH SHALL NOT EXCEED 0.006" (0.152mm) PER SIDE **DIMENSIONS DO NOT INCLUDE INTERLEAD FLASH. INTERLEAD FLASH SHALL NOT EXCEED 0.010" (0.254mm) PER SIDE 0.002 - 0.008 (0.05 - 0.21) 0.010 - 0.015 (0.25 - 0.38) G28 SSOP 0694 RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LTC1321 Dual RS232/RS485 Transceiver Two RS232 Driver/Receiver Pairs or Two RS485 Driver/Receiver Pairs LTC1334 Single 5V RS232/RS485 Multiprotocol Transceiver Two RS232 Driver/Receiver or Four RS232 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 LTC1544 Software-Selectable Multiprotocol Transceiver 4-Driver/4-Receiver for Control Signals Including LL LTC1545 Software-Selectable Multiprotocol Transceiver 5-Driver/5-Receiver for Control Signals Including LL, RL and TM LTC1546 Software-Selectable Multiprotocol Transceiver with Termination 3-Driver/3-Receiver for Data and Clock Signals LTC2844 3.3V Multiprotocol Transceiver 4-Driver/4-Receiver for Control Signals Including LL LTC2845 3.3V Multiprotocol Transceiver 5-Driver/5-Receiver for Control Signals Including LL, RL and TM LTC2846 3.3V Multiprotocol Transceiver with Termination 3-Driver/3-Receiver for Data and Clock Signals sn1534 1543fas 20 Linear Technology Corporation LW/TP 1002 1K REV A * PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 FAX: (408) 434-0507 www.linear.com LINEAR TECHNOLOGY CORPORATION 1998