The ADM2483BRWZ-REEL 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., theADM2483BRWZ-REEL 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 ADM2483BRWZ-REEL 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 VDD1 or VDD2 = 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.

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