The DS1487 is a low-power transceiver for RS-485 and RS-422 communication. The device contains one driver and one receiver. The drivers slew rate allows for operation up to 2.0 Mbps (see Applications Information section). The transceiver presents ¼ unit loading to the RS-485 bus allowing up to 128 nodes to be connected together without the use of repeaters.

The transceiver draws 200 µA of supply current when unloaded or fully loaded with the driver disabled and operates from a single +5V supply.

The driver is short-circuit current limited and is protected against excessive power dissipation by thermal shutdown circuitry that places the driver outputs into TRI-STATE (High Impedance state) under fault conditions. The driver guarantees a minimum of 1.5V differential output voltage with maximum loading across the common mode range (VOD3).

The receiver has a failsafe feature that guarantees a logic-high output if the input is open circuit.

The DS1487 is available in surface mount and DIP packages.

• Meets TIA/EIA RS-485 multipoint standard
• Allows up to 128 transceivers on the bus (¼ U.L.)
• Guaranteed full load output voltage (VOD3)
• Low quiescent current: 200 µA typ
• -7V to +12V common-mode input voltage range
• TRI-STATE outputs on driver and receiver
• AC performance:
  • Driver transition time: 25 ns typ
  • Driver propagation delay: 40 ns typ
  • Driver skew: 1 ns typ
  • Receiver propagation delay: 200 ns typ
  • Receiver skew: 20 ns typ
• Half-duplex flow through pinout
• Operates from a single 5V supply
• Current-limiting and thermal shutdown for driver overload protection
• Pin and functional compatible with MAX1487

TRI-STATE® is a registered trademark of National Semiconductor Corporation.