Overview: ® ISL4485E
Data Sheet December 2003 FN6049.1 ±15kV ESD Protected, 20Mbps, 5V, Low
Power, RS-485/RS-422 Transceiver
The Intersil ISL4485E is a high speed, BiCMOS 5V powered, single transceiver that meets both the RS-485 and RS-422 standards for balanced munication. Each driver output/receiver input is protected against ±15kV ESD strikes, without latch-up. Unlike petitive 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 bees 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.
