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

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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.
MAX1490A, MAX1490B: Pin Configuration MAX1490A, MAX1490B: Pin Configuration Enlarge+

Key Features

  • 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


  • 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
Part NumberTx/RxDuplexVSUPPLY
Galvanic Isolation
Data Rate
Tx ENRx ENICC (Shutdn.)
Rx/Tx on BusRx Failsafe w/ InputsSlew Rate LimitingOper. Temp.
typmintypSee Notes
MAX1480A 1Tx + 1RxHalf51000602500YesNo0.2128OpenNo
-40 to +85
0 to +70
$20.15 @1k
MAX1480B Half35250Yes128
$15.39 @1k
MAX1480C Half35250Yes128
$15.39 @1k
MAX1490A Full1002500No32
$21.48 @1k
MAX1490B Full65250No32
$15.40 @1k
See All RS-485/RS-422 Line Driver/Receivers (205)
Pricing Notes:
This pricing is BUDGETARY, for comparing similar parts. Prices are in U.S. dollars and subject to change. Quantity pricing may vary substantially and international prices may differ due to local duties, taxes, fees, and exchange rates. For volume-specific and version-specific prices and delivery, please see the price and availability page or contact an authorized distributor.

Technical Documents

App Note 2116 RS-485 Data Interface Gives Isolated, Full-Duplex Operation

Quality and Environmental Data

Product Reliability Reports: MAX1480A.pdf 
Lead-Free Package Tin (Sn) Whisker Reports

Additional Resources

RS-485 Resources
Device   Fab Process   Technology   Sample size   Rejects   FIT at 25°C   FIT at 55°C  

Note : The failure rates are summarized by technology and mapped to the associated material part numbers. The failure rates are highly dependent on the number of units tested.

Quality Management System >
Environmental Management System >


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