LTC1484 Low Power RS485 Transceiver with Receiver Fail-Safe FEATURES DESCRIPTIO n No Damage or Latchup to 15kV ESD (Human The LTC 1484 is a low power RS485 compatible trans- Body Model), IEC-1000-4-2 Level 4 Contact ( 8kV) ceiver. In receiver mode, it offers a fail-safe feature which and Level 3 ( 8kV) Air Gap Specifications guarantees a high receiver output state when the inputs n Guaranteed High Receiver Output State for Floating, are left open, shorted together or terminated with no Shorted or Terminated Inputs with No Signal signal present. No external components are required to Present ensure the high receiver output state. n Drives Low Cost Residential Telephone Wires Both driver and receiver feature three-state outputs with n Low Power: I = 700m A Max with Driver Disabled CC separate receiver and driver control pins. The driver n I = 900m A Max for Driver Enable with No Load CC outputs maintain high impedance over the entire com- n 20m A Max Quiescent Current in Shutdown Mode mon mode range when three-stated. Excessive power n Single 5V Supply dissipation caused by bus contention or faults is pre- n 7V to 12V Common Mode Range Permits 7V vented by a thermal shutdown circuit that forces the Ground Difference Between Devices on the Data Line driver outputs into a high impedance state. n Power Up/Down Glitch-Free Driver Outputs n Enhanced ESD protection allows the LTC1484 to with- Up to 32 Transceivers on the Bus n stand 15kV (human body model), IEC-1000-4-2 level 4 Pin Compatible with the LTC485 n ( 8kV) contact and level 3 ( 8kV) air discharge ESD Available in 8-Lead MSOP, PDIP and SO Packages without latchup or damage. U The LTC1484 is fully specified over the commercial and APPLICATIO S industrial temperature ranges and is available in 8-lead n Battery-Powered RS485/RS422 Applications MSOP, PDIP and SO packages. n Low Power RS485/RS422 Transceiver , LTC and LT are registered trademarks of Linear Technology Corporation. n Level Translator TYPICAL APPLICATIO Driving a 2000 Foot STP Cable RS485 Interface Dl1 LTC1484 LTC1484 RO1 V V RO2 CC1 CC2 B1 B2 R R B2 RE1 RE2 120W 120W A1 A2 DE1 DE2 A2 D D DI1 GND1 GND2 DI2 RO2 1484 TA01 Dl1 DE1 = V 1484 TA01a CC Dl2 = 0 DE2 = 0 RE1 = RE2 = 0 1 U ULTC1484 ABSOLUTE MAXIMUM RATINGS (Note 1) Supply Voltage (V ) ............................................... 6.5V Junction Temperature .......................................... 125 C CC Control Input Voltages ................. 0.3V to (V + 0.3V) Operating Temperature Range CC Driver Input Voltage ..................... 0.3V to (V + 0.3V) LTC1484C ......................................... 0 C T 70 C CC A Driver Output Voltages ................................. 7V to 10V LTC1484I ...................................... 40 C T 85 C A Receiver Input Voltages (Driver Disabled) .. 12V to 14V Storage Temperature Range ................. 65 C to 150 C Receiver Output Voltage ............... 0.3V to (V + 0.3V) Lead Temperature (Soldering, 10 sec).................. 300 C CC PACKAGE/ORDER INFORMATION ORDER PART ORDER PART TOP VIEW NUMBER NUMBER TOP VIEW RO 1 8 V CC LTC1484CMS8 LTC1484CN8 RO 1 8 V R CC RE 2 7 B 7 B RE 2 LTC1484CS8 DE 3 6 A DE 3 6 A LTC1484IN8 D 5 GND DI 4 DI 4 5 GND LTC1484IS8 MS8 PACKAGE 8-LEAD PLASTIC MSOP MS8 PART MARKING N8 PACKAGE S8 PACKAGE 8-LEAD PDIP 8-LEAD PLASTIC SO S8 PART MARKING T = 125 C, q = 200 C/ W JMAX JA T = 125 C, q = 130 C/ W (N8) JMAX JA LTDX T = 125 C, q = 135 C/ W (S8) JMAX JA 1484 1484I Consult factory for Military grade parts. ELECTRICAL CHARACTERISTICS The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at T = 25 C. V = 5V 5% (Notes 2 and 3) unless otherwise noted. A CC SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS V Differential Driver Output Voltage (Unloaded) I = 0 l V V OD1 OUT CC V Differential Driver Output Voltage (with Load) R = 50W (RS422) l2V OD2 R = 27W (RS485) Figure 1 l 1.5 5 V R = 22W , Figure 1 l 1.5 5 V V Differential Driver Output Voltage V = 7V to 12V, Figure 2 l 1.5 5 V OD3 TST (with Common Mode) D V Change in Magnitude of Driver Differential R = 22W , 27W or R = 50W , Figure 1 l 0.2 V OD Output Voltage for Complementary Output States V = 7V to 12V, Figure 2 TST V Driver Common Mode Output Voltage R = 22W , 27W or R = 50W , Figure 1 l 3V OC D V Change in Magnitude of Driver Common Mode R = 22W , 27W or R = 50W , Figure 1 l 0.2 V OC Output Voltage for Complementary Output States V Input High Voltage DE, DI, RE l 2.0 V IH V Input Low Voltage DE, DI, RE l 0.8 V IL I Input Current DE, DI, RE l 2 m A IN1 I Input Current (A, B) DE = 0, V = 0 or 5V, V = 12V l 1.0 mA IN2 CC IN DE = 0, V = 0 or 5V, V = 7V l 0.8 mA CC IN V Differential Input Threshold Voltage for Receiver 7V V 12V, DE = 0 l 0.20 0.015 V TH CM 2 U W U W U WW