The MAX481E, MAX483E, MAX485E, MAX487E-MAX491E, and MAX1487E are low-power transceivers for RS-485 and RS-422 communications in harsh environments. Each driver output and receiver input is protected against ±15kV electro-static discharge (ESD) shocks, without latchup. These parts contain one driver and one receiver. The MAX483E, MAX487E, MAX488E, and MAX489E feature reduced slew-rate drivers that minimize EMI and reduce reflections caused by improperly terminated cables, thus allowing error-free data transmission up to 250kbps. The driver slew rates of the MAX481E, MAX485E, MAX490E, MAX491E, and MAX1487E are not limited, allowing them to transmit up to 2.5Mbps. These transceivers draw as little as 120µA supply current when unloaded or when fully loaded with disabled drivers (see Selector Guide). Additionally, the MAX481E, MAX483E, and MAX487E have a low-current shutdown mode in which they consume only 0.5µA. All parts operate from a single +5V supply. Drivers are short-circuit current limited, and are protected against excessive power dissipation by thermal shutdown circuitry that places their outputs into a high-impedance state. The receiver input has a fail-safe feature that guarantees a logic-high output if the input is open circuit. The MAX487E and MAX1487E feature quarter-unit-load receiver input impedance, allowing up to 128 transceivers on the bus. The MAX488E-MAX491E are designed for full-duplex communication.
The MAX481E, MAX483E, MAX485E, MAX487E, MAX491E, and MAX1487E are low‑power RS‑485/RS‑422 transceivers designed for harsh environments. Each part integrates a driver and a receiver, offers +15 kV ESD protection, and operates from a single +5 V supply.
Key features include slew‑rate‑limited drivers for reduced EMI, low quiescent current (as low as 120 µA), a shutdown mode consuming only 0.5 µA, and the ability to place up to 128 transceivers on a single bus. The document lists absolute maximum ratings, detailed electrical characteristics, pin configurations, typical application circuits, and ordering information.
| ESD protection | +15 kV (Human Body Model) |
|---|---|
| Quiescent current (typical) | 120 µA (MAX483E/487E/488E/489E) |
| Supply voltage range | 4.75 V to 5.25 V |
| Maximum data rate (half‑duplex) | 2.5 Mbps |
| Maximum bus load | 128 transceivers |
| Shutdown current | 0.5 µA |
The half‑duplex devices can transmit up to 2.5 Mbps.
Up to 128 transceivers can be placed on the bus.
In shutdown mode the parts consume only 0.5 µA.
The devices operate with a VCC between 4.75 V and 5.25 V.