PDF, 175 Kb, File published: May 10, 2004
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DS1487 DS1487 Low Power RS-485 Вј Unit Load Multipoint Transceiver Literature Number: SNLS132 DS1487
Low Power RS-485 1вЃ„4 Unit Load Multipoint Transceiver
General Description Features 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 1вЃ„4 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 ВµA 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 В®
(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. n Connection and Logic Diagram Truth Table Meets TIA/EIA RS-485 multipoint standard
Allows up to 128 transceivers on the bus (1вЃ„4 U.L.)
Guaranteed full load output voltage (VOD3)
Low quiescent current: 200 ВµA typ
-7V to +12V common-mode input voltage range …
