DS1487 Datasheet | National Semiconductor

Description Unit Load Multipoint Transceiver Features Y Y Y Y Y Y Y The DS1487 is a low-power transceiver for RS-485 and RS-422 munication 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 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 m A of supply current when unloaded or fully loaded with the driver disabled and operates from a single a 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 mon mode range (VOD3) The receiver has a failsafe feature that guarantees a logichigh 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 ( U L ) Guaranteed full load output voltage (VOD3) Low quiescent current 200 m A typ b 7V to a 12V mon-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 patible with MAX1487 Unit Load Multipoint Transceiver Connection and Logic Diagram DIP and SOIC Truth Table DRIVER SECTION RE X X X DE H H L DI H L X A H L Z B L H Z RECEIVER SECTION RE TL F 12920 - 1 DE L L X L A-B t a 0 2V s b 0 2V RO H L Z H Order Number DS1487N DS1487M Temp Range 0 C to a 70 C 0 C to a 70 C Package DIP N08E SOP...