The Intersil ISL3178AE is ±15kV IEC61000 ESD Protected, 3.3V-powered, single transceivers that meet both the RS-485 and RS-422 standards for balanced communication. This device has very low bus currents (+125mA/-100mA), which presents a true "1/8 unit load" to the RS-485 bus. This allows up to 256 transceivers on the network without violating the RS-485 specification's 32 unit load maximum, and without using repeaters. For example, in a remote utility meter reading system, individual meter readings are routed to a concentrator via an RS-485 network, so the high allowed node count minimizes the number of repeaters required.

Receiver (Rx) inputs feature a "Full Fail-Safe" design, which ensures a logic high Rx output if Rx inputs are floating, shorted, or terminated but undriven.

Hot Plug circuitry ensures that the Tx and Rx outputs remain in a high impedance state while the power supply stabilizes. The ISL3178AE is a half duplex version. It multiplexes the Rx inputs and Tx outputs to allow transceivers with output disable functions in an 8 Ld package.

• IEC61000 ESD Protection on RS-485 I/O Pins: ±15kV
  • Class 3 ESD Level on all Other Pins: >7kV HBM
• Full Fail-safe (Open, Short, Terminated/Floating) Receivers
• Hot Plug - Tx and Rx Outputs Remain Three-state During Power-up (Only Versions with Output Enable Pins)
• True 1/8 Unit Load Allows up to 256 Devices on the Bus
• Single 3.3V Supply
• High Data Rates: up to 10Mbps
• Low Quiescent Supply Current: 800μA (Max)
  • Ultra Low Shutdown Supply Current: 10nA
• -7V to +12V Common Mode Input/Output Voltage Range
• Half Duplex Pinouts
• Three State Rx and Tx Outputs Available
• Current Limiting for Driver Overload Protection
• Pb-Free (RoHS Compliant)

• Automated Utility Meter Reading Systems
• High Node Count Systems
• Field Bus Networks
• Security Camera Networks
• Building Environmental Control/Lighting Systems
• Industrial/Process Control Networks