5V, Fail-Safe, 40Mbps, PROFIBUS RS-485/RS-422 Transceivers

The MAX3465-MAX3469 are high-speed differential bus transceivers for RS-485 and RS-422 communications. They are designed to meet TIA/EIA-422-B, TIA/EIA-485-A, V.11, and X.27 standards. The transceiver complies with the PROFIBUS specification providing +2.1V minimum output level with a 54Ω load, 40Mbps data rate, and output skew less than 2ns. Each part contains one three-state differential line driver and one differential input line receiver. The devices operate from a +5V supply and feature true fail-safe circuitry, which guarantees a logic-high receiver output when the receiver inputs are open or shorted. This enables all receiver outputs on a terminated bus to output logic highs when all transmitters are disabled.

All devices feature a 1/4-standard-unit load receiver input impedance that allows 128 transceivers on the bus. Driver and receiver propagation delays are guaranteed under 20ns for multidrop, clock distribution applications. Drivers are short-circuit current limited and are protected against excessive power dissipation by thermal-shutdown circuitry. The driver and receiver feature active-high and active-low enables, respectively, that can be connected together externally to serve as a direction control.

Applications

* High-Speed RS-422 Communications * High-Speed RS-485 Communications * Industrial-Control Local Area Networks * Level Translators * PROFIBUS Applications

* Recommended for PROFIBUS Applications

* Up to 40Mbps Data Rate

* 15ns Transmitter Propagation Delay

* 20ns Receiver Propagation Delay

* 2ns Transmitter and Receiver Skew

* High Differential Driver Output Level (2.1V on 54Ω)

* Hot-Swap Versions

* 1µA Shutdown Supply Current

* Low Supply Current Requirements (2.5mA, typ)

* Allow Up to 128 Transceivers on the Bus

* True Fail-Safe Receiver while Maintaining EIA/TIA-485 Compatibility

* Designed for Multipoint Transmissions on Long or Noisy Bus Lines

* Full-Duplex and Half-Duplex Versions Available

* Phase Controls to Correct for Twisted-Pair Reversal for 14-Pin Versions

* Current-Limiting and Thermal Shutdown for Driver Overload Protection