19-1775; Rev 0; 2/01 +5V Multiprotocol, Software-Selectable Cable Terminator Features ♦ Certified TBR-1 and TBR-2-Compliant Chipset (NET1 and NET2)—Pending Completion of Testing ♦ Supports V.10 (RS-423), V.11 (RS-422, RS-530, RS-530A, RS-449, V.36, and X.21), V.28 (RS-232) and V.35 Termination ♦ Cable- or Software-Selectable Termination ♦ Cable- or Software-Selectable DTE/DCE ♦ Replaces Discrete Resistor Termination Networks and Expensive Relays The MXL1344A terminator is designed to form a complete +5V cable- or software-selectable multiprotocol DCE/DTE interface port when used with the MXL1543 and MXL1544/MAX3175 transceiver ICs. The MXL1344A terminator can use the VEE power generated by the MXL1543 charge pump, simplifying system design. The MXL1344A, MXL1543, and MXL1544/MAX3175 are pinfor-pin compatible with the LTC1344A, LTC1543, and LTC1544, but for proper operation the entire Maxim chipset must be used without substituting other manufacturer's parts on a chip-by-chip basis. ♦ Available in Small 24-Pin SSOP Package Applications Data Networking PCI Cards CSU and DSU Telecommunication Equipment Data Routers Data Switches Ordering Information PART The MXL1344A is available in a 24-pin SSOP package and is specified for the 0°C to +70°C commercial temperature range. TEMP. RANGE MXL1344ACAG 0°C to +70°C PIN-PACKAGE 24 SSOP Pin Configuration appears at end of data sheet. Typical Operating Circuit D4 LL CTS DSR R4 R3 R2 R1 MXL1544/ MAX3175 DCD DTR RTS D3 D2 D1 RXD RXC R3 R2 TXC MXL1543 R1 D3 SCTE TXD D2 D1 MXL1344A 18 13 5 10 8 22 6 23 20 19 4 1 7 16 3 9 17 12 15 11 24 14 2 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 (102) SHIELD (101) RTS A (105) RTS B DTR A (108) DTR B DCD A (107) DCD B DSR A (109) DSR B CTS A (106) CTS B LL A (141) DB-25 CONNECTOR ________________________________________________________________ Maxim Integrated Products 1 For price, delivery, and to place orders, please contact Maxim Distribution at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com. MXL1344A General Description The MXL1344A contains six software-selectable, 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 100Ω differential 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 termination protocol can be selected by the serial interface cable wiring or by software control. The MXL1344A replaces discrete resistor termination networks and expensive relays required for multiprotocol termination, saving space and cost. MXL1344A +5V Multiprotocol, Software-Selectable Cable Terminator ABSOLUTE MAXIMUM RATINGS All Voltages to GND Unless Otherwise Noted Supply Voltages VCC ........................................................................-0.3V to +6V VEE.........................................................................+0.3V to -7V Logic Input Voltages M0, M1, M2, DCE/DTE, LATCH.............................-0.3V to +6V Termination Network Inputs R_A, R_B ..............................................................-15V to +15V R_A to R_B........................................................................±15V Continuous Power Dissipation (TA = +70°C) 24-Pin SSOP (derate 8mW/°C above +70°C) ...............640mW Operating Temperature Range...............................0°C to +70°C Die Temperature ..............................................................+150°C Storage Temperature Range .............................-65°C to +150°C Lead Temperature (soldering, 10s) .................................+300°C Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. ELECTRICAL CHARACTERISTICS (VCC = +5V ±5%, VEE = -5V ±5%, TA = 0°C to 70°C, unless otherwise noted. Typical values are at TA = +25°C, VCC = +5V, VEE = -5V, unless otherwise noted.) PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS 0.4 1.0 mA DC CHARACTERISTICS VCC Supply Current ICC All logic inputs = GND or VCC TERMINATOR PINS Differential-Mode Impedance V.35 Mode -2V ≤ VCM ≤ +2V, all loads, Figure 1 90 104 110 Ω Common-Mode Impedance V.35 Mode -2V ≤ VCM ≤ +2V, all loads, Figure 2 135 153 165 Ω Differential-Mode Impedance V.11 Mode VCM = 0V, all loads 100 104 110 -7V ≤ VCM ≤ +7V, all loads, TA = +25°C 100 104 -7V ≤ VCM ≤+7V, all loads -50 High-Impedance Leakage Current IZ 50 Ω µA LOGIC INPUTS (M0, M1, M2, LATCH, DCE/DTE) Input High Voltage VIH Input Low Voltage VIL Logic Input Current 2 IIH, IIL 2.0 VIN = VCC or GND _______________________________________________________________________________________ V 0.8 V ±10 µA +5V Multiprotocol, Software-Selectable Cable Terminator V.11 OR V.35 DIFFERENTIAL-MODE IMPEDANCE vs. COMMON MODE VOLTAGE 104.5 VCM = +7V 104.0 105 IMPEDANCE (Ω) 105 VCM = 0 105.0 110 MXL1344A toc02 VCM = -7V IMPEDANCE (Ω) IMPEDANCE (Ω) 105.5 110 MXL1344A toc01 106.0 V.11 OR V.35 DIFFERENTIAL-MODE IMPEDANCE vs. SUPPLY VOLTAGE (VCC) MXL1344A toc03 V.11 OR V.35 DIFFERENTIAL-MODE IMPEDANCE vs. TEMPERATURE 100 95 100 95 103.5 103.0 90 0 10 20 30 40 50 60 90 -7 70 -5 -3 -1 1 3 5 7 4.50 4.75 5.00 5.25 5.50 TEMPERATURE (°C) VCM (V) VCC (V) V.11 OR V.35 DIFFERENTIAL-MODE IMPEDANCE vs. SUPPLY VOLTAGE (VEE) V.35 COMMON-MODE IMPEDANCE vs. TEMPERATURE V.35 COMMON-MODE IMPEDANCE vs. COMMON-MODE VOLTAGE (VCM) 160 MXL1344A toc06 165 MXL1344A toc05 165 MXL1344A toc04 110 160 100 155 IMPEDANCE (Ω) IMPEDANCE (Ω) IMPEDANCE (Ω) 105 150 145 155 150 145 95 140 135 -5.25 -5.00 -4.75 135 0 10 20 30 40 50 60 VEE (V) TEMPERATURE (°C) V.35 COMMON-MODE IMPEDANCE vs. SUPPLY VOLTAGE (VCC) V.35 COMMON-MODE IMPEDANCE vs. SUPPLY VOLTAGE (VEE) 150 145 140 155 150 145 4.7 4.9 5.1 VCC (V) 5.3 5.5 1 2 450 IEE 400 350 300 250 200 ICC 150 100 135 4.5 0 SUPPLY CURRENT vs. TEMPERATURE 140 135 -1 500 SUPPLY CURRENT (µA) 160 IMPEDANCE (Ω) 155 -2 MXL1344A toc08 160 70 VCM (V) 165 MXL1344A toc07 165 IMPEDANCE (Ω) -4.50 MXL1344A toc09 90 -5.50 140 -5.5 -5.3 -5.1 -4.9 VEE (V) -4.7 -4.5 0 10 20 30 50 40 TEMPERATURE (°C) 60 70 _______________________________________________________________________________________ 3 MXL1344A Typical Operating Characteristics (VCC = +5V, VEE = -5V, TA = +25°C, unless otherwise noted.) +5V Multiprotocol, Software-Selectable Cable Terminator MXL1344A Pin Description PIN NAME FUNCTION 1 M0 Mode-Select Pin (Table 1) 2 VEE Negative Supply Voltage (typically connected to VEE of MXL1543*). Bypass to GND with a 0.1µF capacitor. 3 R1C Load 1, Center Tap 4 R1B Load 1, Node B 5 R1A Load 1, Node A 6 R2A Load 2, Node A 7 R2B Load 2, Node B 8 R2C Load 2, Center Tap 9 R3A Load 3, Node A 10 R3B Load 3, Node B 11 R3C Load 3, Center Tap 12, 13 GND Ground 14 VCC +5V Supply Voltage. Bypass to GND with a 0.1µF capacitor. 15 R4B Load 4, Node B 16 R4A Load 4, Node A 17 R5B Load 5, Node B 18 R5A Load 5, Node A 19 R6A Load 6, Node A 20 R6B Load 6, Node B 21 LATCH 22 DCE/ DTE 23 M2 Mode-Select Pin (Table 1) 24 M1 Mode-Select Pin (Table 1) Latch Signal Input. When LATCH is LOW, the input latches are transparent. When LATCH is high, the data at the mode-select inputs are latched. Logic Level HIGH selects DCE interface, (Table 1) *VEE is typically supplied by the charge pump of the MXL1543. The VEE input level varies with the mode of chipset operation as follows: V.35/V.28 Modes: -6.50V ≤ VEE ≤ -5.45V, in typical operation VEE = -5.80V V.10/V.11 Modes: -4.60V ≤ VEE ≤ -3.80V, in typical operation VEE = -4.20V Detailed Description The MXL1344A contains six software-selectable multiprotocol cable termination networks (Figure 3). Each network is capable of terminating V.11 (RS-422, RS530, RS-530A, RS-449, V.36 and X.21) with a 100Ω differential 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 termination protocol can be selected by the serial interface cable wiring or by software control. The MXL1344A replaces discrete resistor termination net4 works and expensive relays required for multiprotocol termination, saving space and cost. The MXL1344A terminator is designed to form a complete +5V cable- or software-selectable multiprotocol DTE/DCE interface port when used with the MXL1543 and MXL1544/MAX3175 transceivers. The MXL1344A terminator can use the VEE power generated by the MXL1543 charge pump, simplifying system design. The MXL1344A, MXL1543, and MXL1544/MAX3175 are pinfor-pin compatible with the LTC1344A, LTC1543, and LTC1544, but for proper operation, the entire Maxim _______________________________________________________________________________________ +5V Multiprotocol, Software-Selectable Cable Terminator MXL1344A A A I R1 = 52Ω R1 = 52Ω AMMETER S1 ON S1 ON R3 = 127Ω R3 = 127Ω S2 OFF AMMETER VDM = ±2V S2 ON R2 = 52Ω I R2 = 52Ω VCM = ±2V B VCM = ±7V OR ±2V RCM = V RDM = DM I 1 24 23 22 21 M0 B Figure 2. V.35 Common-Mode Impedance Measurement Figure 1. V.11 or V.35 Differential Impedance Measurement 3 VCM I 8 11 12 13 MXL1344A M1 M2 1 2 3 4 5 6 5 4 6 7 9 10 16 15 18 17 19 20 DCE/DTE LATCH VCC VEE 14 2 Figure 3. Block Diagram chipset must be used without substituting other manufacturer's parts on a chip-by-chip basis. Termination Modes The termination networks in the MXL1344A can be set to one of three modes, V.11, V.35, or high impedance (high-Z). As shown in Figure 4, in V.11 mode, switch S1 is closed and switch S2 is open, presenting 104Ω across terminals A and B. In V.35 mode, switches S1 and S2 are both closed, presenting a T-network with 104Ω differential impedance and 153Ω common-mode impedance. In high-Z mode, switches S1 and S2 are both open, presenting a high impedance across terminals A and B suitable for V.28 and V.10 modes. _______________________________________________________________________________________ 5 MXL1344A +5V Multiprotocol, Software-Selectable Cable Terminator A A A MXL1344A MXL1344A R1 52Ω R1 52Ω S1 CLOSED S1 CLOSED MXL1344A R1 52Ω S1 OPEN C C S2 OPEN S2 CLOSED R3 127Ω R2 52Ω C S2 OPEN R3 127Ω R2 52Ω R2 52Ω B B R3 127Ω B (a) V.11 (b) V.35 (c) Z Figure 4. Termination Modes Table 1. Termination Mode Select Table PROTOCOL V.10/RS-423 RS-530A RS-530 X.21 V.35 RS-449/V.36 V.28/RS-232 No Cable V.10/RS-423 RS-530A RS-530 X.21 V.35 RS-449/V.36 V.28/RS-232 No Cable DCE/ DTE M2 M1 M0 R1 R2 R3 R4 R5 R6 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 0 0 0 0 1 1 1 1 0 0 0 0 1 1 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 0 1 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 Z Z Z Z V.35 Z Z V.11 Z Z Z Z V.35 Z Z V.11 Z Z Z Z V.35 Z Z V.11 Z Z Z Z V.35 Z Z V.11 Z Z Z Z Z Z Z V.11 Z Z Z Z V.35 Z Z V.11 Z V.11 V.11 V.11 V.35 V.11 Z V.11 Z Z Z Z Z Z Z V.11 Z V.11 V.11 V.11 V.35 V.11 Z V.11 Z V.11 V.11 V.11 V.35 V.11 Z V.11 Z V.11 V.11 V.11 V.35 V.11 Z V.11 Z V.11 V.11 V.11 V.35 V.11 Z V.11 Note: Z Indicates high impedance, 1 = high and 0 = low. Z, V.11, and V.35 refer to termination modes (Figure 4.) The state of the MXL1344A’s mode-select pins, M0, M1, M2, and DCE/DTE determines the mode of each of the six termination networks. Table 1 shows a cross-reference of termination mode and select pin state for 6 each of the six termination networks within the MXL1344A. _______________________________________________________________________________________ +5V Multiprotocol, Software-Selectable Cable Terminator MXL1344A 100pF 100pF 100pF 3 8 VCC 5V 11 12 13 MXL1344A 14 28 3 0.1µF LATCH 21 CHARGE PUMP 2 25 2 4.7µF 0.1µF 1µF DTE_TXD/DCE_RXD 5 DTE_SCTE/DCE_RXC 6 D2 R3 S GND 11 M0 MXL1543 12 M1 13 M2 14 DCE/DTE 0.1µF VCC 1 28 VCC VEE VDD GND 0.1µF 2 DTE 2 TXD A 14 TXD B 24 SCTE A 11 SCTE B 15 12 17 9 18 17 16 15 R2 10 DTE_RXD/DCE_TXD INTERCONNECT CABLE 20 19 R1 9 DTE_RXC/DCE_SCTE 9 10 16 15 18 17 19 20 22 23 24 1 DCE RXD A RXD B RXC A RXC B D3 8 DTE_TXC/DCE_TXC 6 7 24 23 22 21 D1 7 5 4 DB-25 CONNECTOR SYSTEM PROPRIETARY CONNECTOR M0 27 26 1 1µF DCE/DTE M2 M1 1µF 4.7µF 27 3 16 7 1 TXC A TXC B TXC A TXC B RXC A SCTE A RXC B SCTE B RXD A TXD A RXD B TXD B SIGNAL GND SHIELD M0 M1 M2 DCE/DTE 1µF DTE_RTS/DCE_CTS DTE_DTR/DCE_DSR 3 4 5 DTE_DCD/DCE_DCD DTE_DSR/DCE_DTR 6 7 DTE_CTS/DCE_RTS 8 LOCAL_LOOP_BACK 10 9 D1 D2 26 25 24 23 4 19 20 23 22 21 20 19 18 17 8 DCD A 10 DCD B 6 DSR A 22 DSR B 5 CTS A 13 CTS B 16 18 RTS A RTS B CTS A CTS B DTR A DTR B DSR A DSR B D3 R1 R2 R3 R4 DCD A DCD B DTR A DTR B RTS A RTS B LL D4 11 M0 MXL1544/ MAX3175 12 M1 13 M2 15 14 DCE/DTE INVERT Figure 5. Cable-Selectable Multiprotocol DCE/DTE Serial Interface (Configured in RS-530A DTE Mode) _______________________________________________________________________________________ 7 MXL1344A +5V Multiprotocol, Software-Selectable Cable Terminator No-Cable Mode The MXL1344A enters no-cable mode when the mode select inputs, M0, M1, and M2 are connected HIGH or left unconnected. In no-cable mode, all six termination networks are placed in V.11 mode, with S1 closed and S2 open (Figure 4). the correct termination. The MXL1344A provides a simple solution to this termination problem. All required termination configurations are easily cable- or softwareselectable using the four mode-control input pins M0, M1, M2, and DCE/DTE. Using the MXL1344A in a Multiprotocol Serial Interface Applications Information Older multiprotocol interface termination circuits have been constructed using expensive relays with discrete resistors, custom cables with built-in termination, or complex circuit-board configurations to route signals to BALANCED INTERCONNECTING CABLE GENERATOR LOAD CABLE RECEIVER TERMINATION A′ A 100Ω MIN B B′ C C′ The MXL1344A terminator is designed to form a complete +5V cable- or software-selectable multiprotocol DCE/DTE interface port when used with the MXL1543 and MXL1544/MAX3175 differential driver/receivers. The MXL1344A terminator is designed to use the VEE power generated by the MXL1543’s charge pump and will meet all data sheet specifications when connected as illustrated in Figure 5. The mode-selection tables of all three devices are identical, allowing the M0, M1, M2, and DCE/DTE pins of each device to be connected to a single 4-wire control bus. The MXL1543 and MXL1544/ MAX3175 provide internal pullups for the four lines, forcing them to the logic high state if they are not grounded. This allows interface-mode configuration by simply strapping the appropriate pins to ground in the interconnect cable. In Figure 5, M1, M2 and DCE/DTE are shorted to the cable ground, forcing logic LOW on these control lines. Input M0 is left floating and will be pulled HIGH by internal pullups on the MXL1543 and MXL1544/ Figure 6. Typical V.11 Interface A′ A MXL1543 R5 30kΩ R1 52Ω R8 5kΩ MXL1344A R6 10kΩ RECEIVER S3 S1 R3 127Ω S2 R7 10kΩ R2 52Ω B′ R4 30kΩ B C′ GND Figure 7. V.11 Termination and Internal Resistance Networks 8 _______________________________________________________________________________________ +5V Multiprotocol, Software-Selectable Cable Terminator LOAD A′ A 50Ω MXL1344A BALANCED INTERCONNECTING CABLE GENERATOR 125Ω CABLE TERMINATION 125Ω 50Ω RECEIVER 50Ω 50Ω B B′ C C′ Figure 8. Typical V.35 Interface A′ A MXL1543 R5 30kΩ R1 52Ω R8 5kΩ MXL1344A R6 10kΩ RECEIVER S3 S1 R3 127Ω S2 R7 10kΩ R2 52Ω B′ R4 30kΩ B C′ GND Figure 9. V.35 Termination and Internal Resistance Networks MAX3175. With this cable wiring, the multiprotocol serial port is set in RS-530A DTE mode (Table 1). V.11 Termination A standard V.11 interface is shown in Figure 6. For high-speed data transmission, the V.11 specification recommends terminating the cable at the receiver with a 100Ω (min) resistor. The resistor, although not required, prevents reflections from corrupting transmitted data. In Figure 7, the MXL1344A is used to terminate the V.11 receiver on the MXL1543. Internal to the MXL1344A, S1 is closed and S2 is open to present a 104Ω typical differential resistance and high-Z common-mode impedance. The MXL1543's internal V.28 termination is disabled by opening S3. The V.11 specification allows for signals with commonmode variations of ±7V and differential signal amplitudes from 2V to 6V with data rates as high as 10Mbps. The MXL1344A maintains termination impedance between 100Ω and 110Ω over these conditions. V.35 Termination Figure 8 shows a standard V.35 interface. The generator and the load must both present a 100Ω ±10Ω differential impedance and a 150Ω ±15Ω common-mode impedance. The V.35 driver generates a current output (±11mA typ) that develops an output voltage between 440mV and 660mV across the load termination networks. In Figure 9, the MXL1344A is used to implement the resistive T-network that is needed to properly terminate _______________________________________________________________________________________ 9 MXL1344A +5V Multiprotocol, Software-Selectable Cable Terminator the V.35 receiver. Internal to the MXL1344A, S1 and S2 are closed to connect the T-network resistors to the circuit. The V.35 specification allows for ±4V of ground difference between the V.35 generator and V.35 load, with data rates as high as 10Mbps. The MXL1344A maintains correct termination impedance over these conditions. Compliance Testing A European Standard EN 45001 test report for the MXL1543, MXL1544/MAX3175, and MXL1344A chipset will be available from Maxim upon completion of testing. Contact Maxim Quality Assurance for a copy of the report. V.35 EMI reduction For applications where EMI reduction is especially important, the MXL1344A termination networks provide a pin for shunting common-mode driver currents to GND. Mismatches between the driver A and B output propagation delays can create a common-mode disturbance on the cable. This common-mode energy can be shunted to GND by placing a 100pF capacitor to GND from the center tap of the T-network termination (R1C, R2C and R3C as shown in Figure 5). V.28 Termination Most industry-standard V.28 receivers (including the MXL1543) do not require external termination because the receiver includes an internal 5kΩ termination resistor. When the MXL1344A is placed in V.28 mode, all six of the termination networks are placed in a high-Z mode. In high-Z mode, the MXL1344A termination networks will not interfere with the MXL1543's internal 5kΩ termination. In Figure 10, the MXL1344A and MXL1543 are placed in V.28 mode. Switches S1 and S2 are opened on the MXL1344A to place the network in high-Z mode. Switch S3 is closed on the MXL1543 to enable the 5kΩ terminating resistor. Chip Information TRANSISTOR COUNT: 1,054 PROCESS TECHNOLOGY: BiCMOS Pin Configuration TOP VIEW M0 1 24 M1 VEE 2 23 M2 R1C 3 22 DCE/DTE 21 LATCH R1B 4 R1A 5 MAX1344A 20 R6B R2A 6 19 R6A R2B 7 18 R5A R2C 8 17 R5B R3A 9 16 R4A A Complete X.21 Interface R3B 10 15 R4B A complete DTE-to-DCE interface operating in X.21 mode is shown in Figure 11. The MXL1344A terminates the V.11 clock and data signals. The MXL1543 carries the clock and data signals, and the MXL1544/MAX3175 carries the control signals. The control signals generally do not require external termination. R3C 11 14 VCC GND 12 13 GND 10 24 SSOP ______________________________________________________________________________________ +5V Multiprotocol, Software-Selectable Cable Terminator MXL1344A A′ A MXL1543 R5 30kΩ R1 52Ω R8 5kΩ MXL1344A R6 10kΩ RECEIVER S3 S1 R3 127Ω S2 R7 10kΩ R2 52Ω B′ R4 30kΩ B C′ GND Figure 10. V.28 Termination and Internal Resistance Networks DTE SERIAL CONTROLLER MXL1543 DCE MXL1344A MXL1344A TXD D1 TXD SCTE D2 SCTE D3 TXC R1 RXC R2 RXD R3 104Ω 104Ω MXL1543 SERIAL CONTROLLER R3 TXD R2 SCTE R1 104Ω 104Ω 104Ω TXC D3 TXC RXC D2 RXC RXD D1 RXD MXL1544/MAX3175 MXL1544/MAX3175 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 D4 R4 LL R4 LL D4 Figure 11. DTE-to-DCE X.21 Interface ______________________________________________________________________________________ 11 +5V Multiprotocol, Software-Selectable Cable Terminator SSOP.EPS MXL1344A Package Information Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time. 12 ____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 © 2001 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.