_______________General Description

The MAX481, MAX483, MAX485, MAX487–MAX491, and

MAX1487 are low-power transceivers for RS-485 and RS-

422 communication. Each part contains one driver and one

receiver. The MAX483, MAX487, MAX488, and MAX489

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 MAX481, MAX485, MAX490,

MAX491, and MAX1487 are not limited, allowing them to

transmit up to 2.5Mbps.

These transceivers draw between 120μA and 500μA of

supply current when unloaded or fully loaded with disabled

drivers. Additionally, the MAX481, MAX483, and MAX487

have a low-current shutdown mode in which they consume

only 0.1μA. 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 the driver 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 MAX487 and MAX1487 feature quarter-unit-load

receiver input impedance, allowing up to 128 MAX487/

MAX1487 transceivers on the bus. Full-duplex communications

are obtained using the MAX488–MAX491, while

the MAX481, MAX483, MAX485, MAX487, and MAX1487

are designed for half-duplex applications.

____________________________Features

© In μMAX Package: Smallest 8-Pin SO

© Slew-Rate Limited for Error-Free Data

Transmission (MAX483/487/488/489)

© 0.1μA Low-Current Shutdown Mode

(MAX481/483/487)

© Low Quiescent Current:

120μA (MAX483/487/488/489)

230μA (MAX1487)

300μA (MAX481/485/490/491)

© -7V to +12V Common-Mode Input Voltage Range

© Three-State Outputs

© 30ns Propagation Delays, 5ns Skew

(MAX481/485/490/491/1487)

© Full-Duplex and Half-Duplex Versions Available

© Operate from a Single 5V Supply

© Allows up to 128 Transceivers on the Bus

(MAX487/MAX1487)

© Current-Limiting and Thermal Shutdown for

Driver Overload Protection