Complete, Isolated RS-485/RS-422 Data Interface

The MAX1480A/MAX1480B/MAX1480C/MAX1490A/MAX1490B are complete, electrically isolated, RS-485/RS-422 data-communications interface solutions in a hybrid microcircuit. Transceivers, optocouplers, and a transformer provide a complete interface in a standard DIP package. A single +5V supply on the logic side powers both sides of the interface.

The MAX1480B/MAX1480C/MAX1490B feature reduced-slew-rate drivers that minimize EMI and reduce reflections caused by improperly terminated cables, allowing error-free data transmission at data rates up to 250kbps. The MAX1480A/MAX1490A driver slew rate is not limited, allowing transmission rates up to 2.5Mbps. The MAX1480A/B/C are designed for half-duplex communication, while the MAX1490A/B feature full-duplex communication.

Drivers are short-circuit current limited and 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 known output (active-low RO low for the MAX1480A/B/C, RO high for the MAX1490A/B) if the input is open circuit.

The MAX1480A/MAX1480B/MAX1480C/MAX1490A/MAX1490B typically withstand 1600VRMS (1 minute) or 2000VRMS (1 second). Their isolated outputs meet all RS-485/RS-422 specifications. The MAX1480A/B/C are available in a 28-pin DIP package, and the MAX1490A/B are available in a 24-pin DIP package.

Applications

* Automated Test Equipment (ATE) * HVAC/Building Control Networks * Industrial-Control Local Area Networks * Isolated RS-485/RS-422 Data Interface * Transceivers for EMI-Sensitive Applications

* For Integrated ESD Protection

* MAX1480E/MAX1490E: ±15kV ESD-Protected, Isolated RS-485/RS-422 Data Interfaces

* For Space-Constrained Applications

* MAX3157: High CMRR, RS-485 Transceiver with ±50V Isolation