The fastest 5-V fractional-unit load full duplex RS-485/422 transceiver?

Milpitas, CA, May 26, 2004 — Intersil Corporation, a world leader in the design and manufacture of high performance analog solutions, today announced two new LINEARLINK full-duplex RS-485/422 transceivers, the ISL4489E and ISL4491E. The ISL4491E is the world's fastest 5-V, full-duplex, one-eighth fractional-unit load transceiver with 15-kV ESD protection. These new devices boost performance in a wide range of industrial and commercial applications where speed and reach are important.

“The ISL4489E and ISL4491E are exceptional RS-485 speed and reach options that designers can select for new balanced twisted pair networks that contain up to 256 nodes,” said Mamoon Rashid, director of Intersil's Analog Solutions Product Group. You can compare them to the recently introduced ISL8489E and ISL8491E transceivers. “These new transceivers provide extended reach, the highest data integrity and full 15-kV ESD protection to increase reliability and survivability from static discharge events.”

Both the ISL4489E and the ISL4491E are one-eighth fractional-unit load transceivers that enable up to 256 nodes on the bus as compared to only 32 nodes for single-unit load devices. The large number of nodes on a single bus saves cost and complexity in large networks that span a wide area, such as found in factory automation, process control, environmental control or security applications. The ISL4489E is a 250 kbps slew-rate limited device intended for long networks while the ISL4491E is a 15 Mbps device intended for short-run networks at high data transfer rates.

As full-duplex transceivers, the ISL4489E and ISL4491E are configured for four-wire RS-485 networks. Four-wire networks allow simultaneous transmit and receive capability. They may also be used for RS-422 networks where only one driver is allowed on each two-wire bus.

The ICs are ESD protected to 15 kV on all transmit (Tx) and receive (Rx) bus pins and up to 7 kV on all other pins, which greatly improves survivability from random static charges during manufacturing and use. Packaged in a 14-lead SOIC, the devices are rated for the industrial temperature range of -40 to +85°C.

Exceeding the tolerance of many competing parts, these ICs operate with a +/-10 percent tolerance from a 5-V supply (4.5 to 5.5 V range). This relaxes the supply requirements and allows designers to employ a less costly power solution.

ISL4489E and ISL4491E Technical Summary
Full duplex operation
One eighth fractional-unit load for up to 256 nodes per bus
Balanced differential signaling, RS-485 and RS-422 standards compliant
15 kV ESD protected on all Tx and Rx bus pins
7 kV protection on all other pins
Single 5-V supply, +/-10 percent tolerance, 4.5 to 5.5 V range
-7 V to +12 V common-mode input voltage range
Rx inputs feature a “fail-safe-if-open” design, ensures a logic high Rx output if Rx inputs are floating
Driver outputs short circuit protected, even for voltages exceeding the power supply
On-chip thermal shutdown disables the Tx outputs, prevents damage if power dissipation becomes excessive
ISL4489E — 250 kbps
ISL4491E — 15 Mbps
14-lead SOIC package
Industrial temperature range, -40 to +85°C

The ISL4489E and ISL4491E are available now. The suggested resale price in 100 to 999-unit quantities is $1.10 for each IC. ICs are available on tape and reel.

Additional information on these and other high-performance LINEARLINK interface solutions can be obtained online from Intersil's Interface Web site at:

ISL4489E/ISL4491E data sheet

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