The ADM2483 differential bus transceiver is an integrated,galvanically isolated component designed for bidirectional datacommunication on balanced, multipoint bus transmission lines.It complies with ANSI EIA/TIA-485-A and ISO 8482: 1987(E).Using the iCoupler technology from Analog Devices, Inc., theADM2483 combines a 3-channel isolator, a three-state differentialline driver, and a differential input receiver into a single package.The logic side of the device is powered with either a 5 V or 3 Vsupply, and the bus side uses a 5 V supply only.

The ADM2483 is slew-limited to reduce reflections withimproperly terminated transmission lines. The controlled slewrate limits the data rate to 500 kbps. The device’s input impedanceis 96 kΩ, allowing up to 256 transceivers on the bus. Its driverhas an active-high enable feature. The driver differential outputsand receiver differential inputs are connected internally to forma differential input/output (I/O) port.

When the driver is disabled or when V_DD1 or V_DD2 = 0 V, thisimposes minimal loading on the bus. An active-high receiverdisable feature, which causes the receive output to enter a highimpedance state, is provided as well.The receiver inputs have a true fail-safe feature that ensures alogic-high receiver output level when the inputs are open orshorted. This guarantees that the receiver outputs are in aknown state before communication begins and at the pointwhen communication ends.

Current limiting and thermal shutdown features protect againstoutput short circuits and bus contention situations that mightcause excessive power dissipation. The part is fully specifiedover the industrial temperature range and is available in a16-lead, wide body SOIC package.

Applications

• Low power RS-485/RS-422 networks
• Isolated interfaces
• Building control networks
• Multipoint data transmission systems

At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.