BETAMAX4855 V half-duplex RS-485 transceiver
Carry a logic signal across a balanced two-wire bus.
MAX485 connects a controller’s logic-level data to an RS-485 differential bus. One driver and one receiver share terminals A and B, so the link is half duplex: only one node should drive the pair at a time. It does not generate UART framing or implement a protocol by itself. The transceiver runs from a regulated 5 V supply and supports data rates up to 2.5 Mbit/s. DE enables transmission; the active-LOW receiver enable controls RO. Joining those controls provides one direction signal, LOW to receive and HIGH to transmit. The example shows two nodes, termination at both cable ends and one external idle-bias network. A reference conductor keeps the bus common-mode voltage within its operating range. This MAX485 reference does not inherit the shutdown or quarter-unit-load features of other parts in the manufacturer’s family datasheet.
