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The ISL32470E, ISL32472E, ISL32475E, ISL32478E are fault-protected, extended common mode range differential transceivers that exceed the RS-485 and RS-422 standards for balanced communication. The RS-485 bus pins (driver outputs and receiver inputs) are fault protected against overvoltages up to ±60V and are protected against ±16.5kV ESD strikes without latch-up. Additionally, these transceivers operate in environments with common mode voltages up to ±15V (exceeds the RS-485 requirement), making this fault-protected RS-485 family one of the more robust on the market.

Transmitters (Tx) deliver an exceptional 2.5V (typical) differential output voltage into the RS-485 specified 54Ω load. This yields better noise immunity than standard RS-485 ICs or allows up to six 120Ω terminations in star topologies.

Receiver (Rx) inputs feature a "Full Fail-Safe" design, which ensures a logic high Rx output if Rx inputs are floating, shorted, or on a terminated but undriven (idle) bus. Rx outputs feature high drive levels; typically, 15mA @ V_OL = 1V (to ease the design of opto-coupled isolated interfaces).

Half duplex (Rx inputs and Tx outputs multiplexed together) and full duplex pinouts are available. See Table 1 on page 2 for key features and configurations by device number.

For a fault-protected RS-485 transceiver with a ±25V extended common mode range, please see the ISL32490E and ISL32483E data sheets.

Key Features

• Fault-Protected RS-485 Bus Pins: Up to ±60V
• Extended Common Mode Range: ±15V Larger Than Required for RS-485
• 1/4 Unit Load for Up to 128 Devices on the Bus
• ±16.5kV HBM ESD Protection on RS-485 Bus Pins
• High Transient Over-Voltage Tolerance: ±80V
• Full Fail-Safe (Open, Short, Terminated) RS-485 Receivers
• High Rx IOL for Opto-Couplers in Isolated Designs
• Hot Plug Circuitry: Tx and Rx Outputs Remain Three-State DuringPower-Up/Power-Down
• Choice of RS-485 Data Rates: 250kbps to 15Mbps
• Low Quiescent Supply Current: 2.3mA
• Ultra Low Shutdown Supply Current: 10µA

Applications

• Utility Meters/Automated Meter Reading Systems
• High Node Count RS-485 Systems
• PROFIBUS® and RS-485 Based Field Bus Networks, and Factory Automation
• Security Camera Networks
• Building Lighting and Environmental Control Systems
• Industrial/Process Control Networks