LTC1387 Single 5V RS232/RS485 Multiprotocol Transceiver DESCRIPTIO EA U F T RES n Two RS232 Transceivers or One RS485 Transceiver The LTC 1387 is a low power reconfigurable CMOS bidi- n Operates from a Single 5V Supply rectional transceiver. It can be configured as an RS485 n Guaranteed Receiver Output with Inputs differential port or as two RS232 single-ended ports. An Floating or Shorted to Ground onboard charge pump uses four 0.1m F capacitors to n Logic Selectable Fast/Slow RS485 Driver Slew Rate generate boosted positive and negative supplies, allowing n Low Supply Current: 7mA Typical the RS232 drivers to meet 5V output swing require- n 5m A Supply Current in Shutdown ments with only a single 5V supply. A shutdown mode n Self-Testing Capability in Loopback Mode reduces the I supply current to 5m A. CC n Separate Driver and Receiver Enable Controls The RS232 transceivers are in full compliance with RS232 n Driver Maintains High Impedance in Three-State, specification. The RS485 transceiver is in full compliance Shutdown or with Power Off with RS485 and RS422 specifications. The RS485 re- n Receiver Inputs Can Withstand 25V ceiver assumes a known output state when the inputs are floating or shorted to ground. All interface drivers feature U short-circuit and thermal shutdown protection. An enable APPLICATIONS pin allows RS485 driver outputs to be forced into high n Point-of-Sale Terminals impedance which is maintained even when the outputs are n Software Selectable Multiprotocol Interface Ports forced beyond supply rails or the power is off. A loop back n Low Power RS485/RS422/RS232/EIA562 Interface mode allows the driver outputs to be connected back to the n Cable Repeaters receiver inputs for diagnostic self-test. n Level Translators The LTC1387 is available in 20-pin plastic SSOP and SW packages. , LTC and LT are registered trademarks of Linear Technology Corporation. TYPICAL APPLICATI 2 1 20 19 19 20 1 2 3 3 LTC1387 LTC1387 18 V CC2 18 5V V CC1 5V 4 4 17 17 RS485 INTERFACE 5 5 RECOUT RECOUT 120W 120W 6 6 15 15 DR IN 7 7 DR IN 4000-FT 24-GAUGE TWISTED PAIR 14 14 SLEW SLEW 8 9 9 8 5V DR ENABLE DR ENABLE 5V 13 12 13 12 5V 5V 5V 5V 11 10 10 11 ALL CAPACITORS: 0.1m F MONOLITHIC CERAMIC TYPE LTC1387 TA01 1 O U ULTC1387 AB OLUEXAI U RAT GS / S T I PACKAGE ORDER I FOR ATIO (Note 1) ORDER PART Supply Voltage (V ) ............................................. 6.5V TOP VIEW CC NUMBER Input Voltage + + C1 1 20 C2 Drivers ................................... 0.3V to (V + 0.3V) CC C1 2 19 C2 Receivers ............................................. 25V to 25V V 3 18 V LTC1387CG DD CC 485/232, ON, DXEN A 4 17 R LTC1387CSW A B 5 16 R RXEN, SLEW ........................... 0.3V to (V + 0.3V) B LTC1387IG CC Y 6 15 D Y LTC1387ISW Output Voltage Z 7 14 D /SLEW Z Drivers ................................................. 18V to 18V 485/232 8 13 ON Receivers ............................... 0.3V to (V + 0.3V) CC DXEN 9 12 RXEN Short-Circuit Duration GND 10 11 V EE Output ........................................................ Indefinite + + G PACKAGE SW PACKAGE V , V , C1 , C1 , C2 , C2 .......................... 30 sec DD EE 20-LEAD PLASTIC SSOP 20-LEAD PLASTIC SO Operating Temperature Range LTC1387C .............................................. 0 C to 70 C T = 125 C, q = 120 C/W (G) JMAX JA T = 125 C, q = 75 C/W (SW) JMAX JA LTC1387I ........................................... 40 C to 85 C Storage Temperature Range ................ 65 C to 150 C Lead Temperature (Soldering, 10 sec)................ 300 C Consult factory for Military grade parts. DC ELECTRICAL CHARACTERISTICS T = 25 C, V = 5V, C1 = C2 = C3 = C4 = 0.1m F (Notes 2, 3), unless otherwise noted. A CC SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS RS485 Driver (485/232 = High, ON = DXEN = High) V Differential Driver Output Voltage (Unloaded) I = 0 l 6V OD1 O V Differential Driver Output Voltage (With Load) Figure 1, R = 50W (RS422) l 2.0 6 V OD2 Figure 1, R = 27W (RS485) l 1.5 6 V D V Change in Magnitude of Driver Differential Figure 1, R = 27W or R = 50W l 0.2 V OD Output Voltage for Complementary Output States V Driver Common Mode Output Voltage Figure 1, R = 27W or R = 50W l 3V OC D V Change in Magnitude of Driver Common Mode Figure 1, R = 27W or R = 50W l 0.2 V OC Output Voltage for Complementary Output States I Driver Short-Circuit Current V = 7V, 12V V = High l 35 250 mA OSD O O V = 7V, 12V V = Low (Note 4) l 10 250 mA O O I Three-State Output Current (Y, Z) 7V V 12V 5 500 m A OZD O RS232 Driver (485/232 = Low, ON = DXEN = High) V Output Voltage Swing Figure 4, R = 3k, Positive l 5 6.5 V O L Figure 4, R = 3k, Negative l 5 6.5 V L I Output Short-Circuit Current V = 0V l 17 60 mA OSD O Driver Inputs and Control Inputs V Input High Voltage D , D , DXEN, RXEN, ON, 485/232, SLEW l2V Y Z IH V Input Low Voltage D , D , DXEN, RXEN, ON, 485/232, SLEW l 0.8 V Y Z IL I Input Current D , D , DXEN, RXEN, ON, 485/232 l 0.1 10 m A Y Z IN SLEW (Note 5) l 5 15 m A 2 U WU U W W W