ISL83084E

Description

The ISL8308xE are BiCMOS, ESD protected, 5V powered, single transceivers that meet both the RS-485 and RS-422 standards for balanced communication. Each driver output, and receiver input, is protected against 15kV ESD strikes without latch-up, and unlike competitive products, this Intersil family is specified for 10% tolerance supplies (4.5V to 5.5V). These devices have very low bus currents (+125A/-75A), so they present a true 1/8 unit load to the RS-485 bus. This allows up to 256 transceivers on the network without violating the RS-485 specifications 32 unit load maximum, and without using repeaters. For example, in a remote utility meter reading system, individual meter readings are routed to a concentrator via an RS-485 network, so the high allowed node count minimizes the number of repeaters required. Data for all meters is then read out from the concentrator via a single access port, or a wireless link. Receiver (Rx) inputs feature a Full Fail-Safe design, which ensures a logic high Rx output if Rx inputs are floating, shorted, or terminated but undriven. The ISL83080E, ISL83082E, ISL83083E, ISL83084E, ISL83085E utilize slew rate limited drivers which reduce EMI, and minimize reflections from improperly terminated transmission lines, or unterminated stubs in multidrop and multipoint applications. Slew rate limited versions also include receiver input filtering to enhance noise immunity in the presence of slow input signals. Hot Plug circuitry ensures that the Tx and Rx outputs remain in a high impedance state until the power supply has stabilized, and the Tx outputs are fully short circuit protected. The ISL83080E, ISL83083E, ISL83084E, ISL83086E are configured for full duplex (separate Rx input and Tx output pins) applications. The half duplex versions multiplex the Rx inputs and Tx outputs to allow transceivers with output disable functions in 8 Ld packages.