LTC1482 Low Power RS485 Transceiver with Carrier Detect and Receiver Fail-Safe FEATURES DESCRIPTIO n No Damage or Latchup to 15kV (Human Body The LTC 1482 is a low power RS485 compatible trans- Model), IEC1000-4-2 Level 4 ( 8kV) Contact and ceiver that offers an active low carrier detect output. The Level 3 ( 8kV) Air Discharge open-drain carrier detect pin allows several transceivers n Active Low Carrier Detect Output to share the same carrier detect line and can be used to n Guaranteed High Receiver Output State for detect the insertion or removal of a driven RS485/RS422 Floating, Shorted or Terminated Inputs with cable. No Signal Present Enhanced ESD protection allows the LTC1482 to with- n Drives Low Cost Residential Telephone Wires stand 15kV (human body model), IEC-1000-4-2 level 4 n Low Power: I = 700m A Max with Driver Disabled CC ( 8kV) contact and level 3 ( 8kV) air discharge ESD n I = 900m A Max in Driver Mode Without Load CC without latchup or damage. n 20m A Max Quiescent Current in Shutdown Mode n The LTC1482 receiver stays alive at all times except in Single 5V Supply n shutdown. The supply current is a maximum of 700m A 7V to 12V Common Mode Range Permits 7V and 900m A when the driver is disabled and enabled Ground Difference Between Devices on the Data Line n respectively. In shutdown, the quiescent current of the Maximum Data Rate of 4Mbps n LTC1482 drops to a maximum of 20m A. Power Up/Down Glitch-Free Driver Outputs n Up to 32 Transceivers on the Bus When the driver is disabled or the LTC1482 is in shut- n Available in 8-Lead MSOP, PDIP and SO Packages down, the driver outputs are three-stated and remain in a high impedance state over the RS485 common mode U range. APPLICATIO S Excessive power dissipation caused by bus contention or n Battery-Powered RS485/RS422 Applications faults is prevented by a thermal shutdown circuit, which n Low Power RS485/RS422 Transceiver forces the driver outputs into a high impedance state. n Level Translator The LTC1482 is fully specified over the commercial and industrial temperature ranges and is available in 8-lead , LTC and LT are registered trademarks of Linear Technology Corporation. MSOP, PDIP and SO packages. TYPICAL APPLICATIO Carrier Detect Output (2000 Foot STP Cable) RS485 Interface DE1 LTC1482 LTC1482 RO1 V V RO2 CC1 CC2 B1 B2 R R A2 CD1 CD2 120W 120W B2 A1 A2 DE1 DE2 D D DI1/SHDN1 GND1 GND2 DI2/SHDN2 CD2 1482 TA01 DE1 Dl1 = V 1482 TA01a CC DE2 = 0 Dl2 = V CC 1k PULL-UP AT CD 1 U ULTC1482 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 Carrier Detect Voltage ................................. 0.3V to 8V LTC1482C ........................................ 0 C T 70 C A Driver Input Voltage ..................... 0.3V to (V + 0.3V) LTC1482I ...................................... 40 C T 85 C CC A Driver Output Voltages ................................. 7V to 10V Storage Temperature Range .................. 65 C to 150 C Receiver Input Voltages (Driver Disabled) .. 12V to 14V Lead Temperature (Soldering, 10 sec)................... 300 C Receiver Output Voltage ............... 0.3V to (V + 0.3V) CC PACKAGE/ORDER INFORMATION ORDER PART ORDER PART TOP VIEW NUMBER NUMBER TOP VIEW RO 1 8 V CC LTC1482CMS8 LTC1482CN8 RO 1 8 V CC CD 2 7 B CD 2 7 B LTC1482CS8 DE 3 A DE 3 6 A 6 LTC1482IN8 DI/SHDN 4 5 GND DI/SHDN 4 5 GND LTC1482IS8 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 LTCB T = 125 C, q = 135 C/ W (S8) JMAX JA 1482 1482I 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/SHDN l2V IH V Input Low Voltage DE, DI/SHDN l 0.8 V IL I Input Current DE, DI/SHDN l 2 m A IN1 I Input Current (A, B) with Driver Disabled 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 THRO CM 2 U W U W U WW