The MAX3440EMAX3444E fault-protected RS-485 and J1708 transceivers feature 60V protection from signal faults on communication bus lines. Each device contains one differential line driver with three-state output and one differential line receiver with three-state input. The 1/4-unitload receiver input impedance allows up to 128 transceivers on a single bus. The devices operate from a 5V supply at data rates of up to 10Mbps. True fail-safe inputs guarantee a logic-high receiver output when the receiver inputs are open, shorted, or connected to an idle data line. Hot-swap circuitry eliminates false transitions on the data bus during circuit initialization or connection to a live backplane. Short-circuit current-limiting and thermal shutdown circuitry protect the driver against excessive power dissipation, and on-chip 15kV ESD protection eliminates costly external protection devices.