Dual Transmitter/Receiver RS-422/RS-485 16-Pin PDIP Tube

The SN75ALS1177 and SN75ALS1178 dual differential drivers and receivers are integrated circuits designed for bidirectional data communication on multipoint bus transmission lines. They are designed for balanced transmission lines and meet standards TIA/EIA-422-B and TIA/EIA-485-A. The SN75ALS1177 combines dual 3-state differential line drivers and dual 3-state differential input line receivers, both of which operate from a single 5-V power supply. The drivers and receivers have active-high and active-low enables, respectively, which can be externally connected together to function as direction control. The SN75ALS1178 drivers each have an individual active-high enable. Fail-safe design ensures that when the receiver inputs are open, the receiver outputs are always high. The SN75ALS1177 and SN75ALS1178 are characterized for operation from 0°C to 70°C.

Meet or Exceed Standards TIA/EIA-422-B and TIA/EIA-485-A

Designed for Multipoint Bus Transmission on Long Bus Lines in Noisy Environments

Low Supply-Current Requirement 50 mA Max

Driver Positive- and Negative-Current Limiting

Driver Common-Mode Output Voltage Range of-7 V to 12 V

Thermal Shutdown Protection

Driver 3-State Outputs Active-High Enable

Receiver Common-Mode Input Voltage Range of-12 V to 12 V

Receiver Input Sensitivity...±200 mV

Receiver Hysteresis...50 mV Typ

Receiver High Input Impedance...12k O Min

Receiver 3-State Outputs Active-Low Enable for SN75ALS1177 Only

Operate From Single 5-V Supply