5 V, ±15 kV ESD Protected
Half-Duplex, RS-485/RS-422 Transceivers
ESD protection on RS-485 I/O pins
±15 kV human body model
ADM487E: 250 kbps
ADM485E/ADM1487E: 2.5 Mbps
Reduced slew rates for low EMI
−7 V to +12 V common-mode input range
Thermal shutdown and short-circuit protection
8-lead SOIC packages
FUNCTIONAL BLOCK DIAGRAM
The ADM485E/ADM487E/ADM1487E are 5 V, low power
data transceivers with ±15 kV ESD protection suitable for half-
duplex communication on multipoint bus transmission lines.
They are designed for balanced data transmission and comply
with Telecommunication Industry Association/Electronics Indus-
tries Association (TIA/EIA) standards RS-485 and RS-422. The
ADM487E and ADM1487E have a 1/4 unit load receiver input
impedance that allows up to 128 transceivers on a bus, whereas
the ADM485E allows up to 32 transceivers on a bus. Because
only one driver is enabled at any time, the output of a disabled or
power-down driver is three-stated to avoid overloading the bus.
The driver outputs are slew rate-limited to reduce EMI and data
errors caused by reflections from improperly terminated buses.
Excessive power dissipation caused by bus contention or output
shorting is prevented with a thermal shutdown circuit.
The parts are fully specified over the industrial temperature
ranges and are available in 8-lead SOIC packages.
Table 1. Selection Table
Nodes on Bus
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