ISL4485E
5V, Half Duplex, 20Mbps, ±15kV ESD Protected, RS-485/RS-422 Transceiver

Key Features

• Pb-Free Available (RoHS Compliant)
• High Data Rates up to 20Mbps
• RS-485 I/O Pin ESD Protection ±15kV HBM
• Class 3 ESD Level on all Other Pins >7kV HBM
• Operates from a Single +5V Supply (10% Tolerance)
• 1 Unit Load Allows up to 32 Devices on the Bus
• Low Quiescent Current 700µA
• -7V to +12V Common Mode Input Voltage Range
• Three State Rx and Tx Outputs
• 30ns Propagation Delays, 2ns Skew
• Current Limiting and Thermal Shutdown for driver Overload Protection

Description

The Intersil ISL4485E is a high speed, BiCMOS 5V powered, single transceiver that meets both the RS-485 and RS-422 standards for balanced communication. Each driver output/receiver input is protected against ±15kV ESD strikes, without latch-up. Unlike competitive devices, this Intersil device is specified for 10% tolerance supplies (4.5V to 5.5V).

The excellent differential output voltage coupled with high drive-current output stages allow 20Mbps operation over twisted pair networks up to 450 feet in length. The 25kΩ receiver input resistance presents a "single unit load" to the RS-485 bus, allowing up to 32 transceivers on the network. Receiver (Rx) inputs feature a "fail-safe if open" design, which ensures a logic high Rx output if Rx inputs are floating.

Driver (Tx) outputs are short circuit protected, even for voltages exceeding the power supply voltage. Additionally, on-chip thermal shutdown circuitry disables the Tx outputs to prevent damage if power dissipation becomes excessive.

The half duplex configuration multiplexes the Rx inputs and Tx outputs to allow transceivers with Rx and Tx disable functions in 8 lead packages.

Applications

• SCSI "Fast 20" Drivers and Receivers
• Data Loggers
• Security Networks
• Building Environmental Control Systems
• Industrial/Process Control Networks
• Level Translators