ISL3173E
±15kV ESD Protected, 3.3V, Full Fail-Safe, Low Power, High Speed or Slew Rate Limited, RS-485/RS-422 Transceivers

Key Features

• 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 20Mbps
• Low Quiescent Supply Current: 800μA (Max)
• Ultra Low Shutdown Supply Current: 10nA
• -7V to +12V Common Mode Input/Output Voltage Range
• Half and Full Duplex Pinouts
• Three State Rx and Tx Outputs Available
• Current Limiting and Thermal Shutdown for driver Overload Protection
• Tiny MSOP Packages Consume 50% Less Board Space
• Pb-Free (RoHS Compliant)

Description

The Intersil ISL317XE are ±15kV IEC61000 ESD Protected, 3.3V-powered, single transceivers that meet both the RS-485 and RS-422 standards for balanced communication. These devices have very low bus currents (+125mA/-100mA), so they present 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 ISL3170E through ISL3175E utilize slew rate limited drivers which reduce EMI, and minimize reflections from improperly terminated transmission lines, or unterminated stubs in multidrop and multipoint applications. Slew rate limited versions also include receiver input filtering to enhance noise immunity in the presence of slow input signals.

The ISL3170E, ISL3171E, ISL3173E, ISL3174E, ISL3176E, ISL3177E are configured for full duplex (separate Rx input and Tx output pins) applications. The half duplex versions multiplex the Rx inputs and Tx outputs to allow transceivers with output disable functions in 8 Ld packages.

Applications

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