ADM2487E:  2.5 kV Signal Isolated, ESD Protected, Full/Half Duplex RS-485 Transceiver w/ Transformer Driver (500 kbps)

The ADM2482E/ADM2487E are isolated data transceivers with ±15 kV ESD protection and are suitable for high speed, half-duplex or full-duplex communication on multipoint transmission lines. For half-duplex operation, the transmitter outputs and receiver inputs share the same transmission line. Transmitter Output Pin Y is linked externally to Receiver Input Pin A, and Transmitter Output Pin Z to Receiver Input Pin B. The parts are designed for balanced transmission lines and comply with TIA/EIA- 485-A-98 and ISO 8482:1987(E). The devices employ the Analog Devices, Inc., iCoupler® technology to combine a 3-channel isolator, a three-state differential line driver, and a differential input receiver into a single package. An on-chip oscillator outputs a pair of square waveforms that drive an external transformer to provide isolated power. The logic side of the device can be powered with either a 5 V or a 3.3 V supply, and the bus side is powered with an isolated 3.3 V supply.

The ADM2482E/ADM2487E driver has an active high enable, and the receiver has an active low enable. The driver output enters a high impedance state when the driver enable signal is low. The receiver output enters a high impedance state when the receiver enable signal is high.

The device has current-limiting and thermal shutdown features to protect against output short circuits and situations where bus contention might cause excessive power dissipation. The part is fully specified over the industrial temperature range of −40°C to +85°C and is available in a 16-lead, wide-body SOIC package.

Applications

Data Sheet, Rev. A, 3/09