The ISL3259E is a ±15kV IEC61000 ESD protected, 5V powered, single transceiver for balanced communication to RS-485 and RS-422 standards. It also has the larger output voltage and higher data rates (up to 100Mbps) required for high-speed PROFIBUS applications.The low bus current (+220 μA /-150 μA) provides 1/5 unit load for the RS-485 bus.
Pin Configuration
This allows up to 160 transceivers on the network without violating the load limits of the RS-485 specification and without the use of Repeaters. The transceiver requires a 5V power supply and provides a differential output voltage of at least 2.1V. This means better anti-jamming (data integrity), longer coverage, or the ability to drive up to six 120-ω terminals in "star" or other non-standard bus topologies. SCSI applications benefit from the ISL3259E's low receiver and transmitter partial to partial tilt.
ISL3259E is ideal for high-speed parallel applications that need to capture a large number of bits at the same time. Low position tilt relieves time constraints on data latch signals. The receiver (Rx) input has a "complete fail-safe" design that ensures a logically high Rx output if the Rx input floats, shorts out, or terminates but is not driven. The Rx output has a high drive level (usually 30mA@VOL = 1V) to simplify the design of the optical isolation interface.
The hot swap circuit ensures that the Tx and Rx outputs remain in a high impedance state while the power supply is stable. Driver (Tx) output short-circuit protection, even if the voltage exceeds the supply voltage. In addition, the heat off circuit on the chip disables the Tx output to prevent damage if power consumption becomes excessive
Typical Operating Circuit
