LMS1485IM ,5V Low Power RS-485 Differential Bus TransceiverFeaturesn Meet ANSI standard RS-485-A and RS-422-BTheLMS1485isalowpowerdifferentialbus/linetranscei ..
LMS1485M ,5V Low Power RS-485 Differential Bus TransceiverPin DescriptionsPin # I/O Name Function> <1 O RO Receiver Output: If A B by 200 mV, RO will be high ..
LMS1487CM ,5V Low Power RS-485 / RS-422 Differential Bus Transceiverapplications with noisy environmentTypical Application20053001A Typical multipoint application is s ..
LMS1487CMX ,5V Low Power RS-485 / RS-422 Differential Bus TransceiverFeaturesn Meet ANSI standard RS-485-A and RS-422-BTheLMS1487isalowpowerdifferentialbus/linetranscei ..
LMS1487ECM ,5V Low Power RS-485 / RS-422 Differential Bus Transceiverapplicationsn Multipoint
LMS1487ECNA ,5V Low Power RS-485 / RS-422 Differential Bus Transceiverapplications in noisy environments. The LMS1487 is avail-n Network hubs, bridges, and routersable i ..
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LMS1485IM-LMS1485M
5V Low Power RS-485 Differential Bus Transceiver
LMS1485 Low Power RS-485 Differential Bus Transceiver
General DescriptionThe LMS1485isalow power differential bus/line transceiver
designedfor high speed bidirectional data communicationon
multipoint bus transmission lines.Itis designedfor balanced
transmission lines.It meets ANSI Standards TIA/EIA
RS422-B, TIA/EIA RS485-A and ITU recommendation and
V.11 and X.27.
The LMS1485 combinesa TRI-STATE™ differential line
driver and differential input receiver, bothof which operate
froma single 5.0V power supply. The driver and receiver
havean active high and active low, respectively, that canbe
externally connectedto functionasa direction control. The
driver and receiver differential inputs are internally con-
nectedto form differential input/output (I/O) bus ports that
are designedto offer minimum loadingto bus whenever the
driveris disabledor when VCC= 0V. These ports feature
wide positive and negative common mode voltage ranges,
making the device suitable for multipoint applicationsin
noisy environments.
The LMS1485is build with National’s advanced BiCMOS
process andis availableina 8-Pin SOIC package.Itisa
drop-in socket replacementto ADI’s ADM1485 and LTC’s
LT1485.
Features Meet ANSI standard RS-485-A and RS-422-B Data rate 30Mbps Single supply voltage operation,5V Wide input and output voltage range Thermal shutdown protection Short circuit protection Driver propagation delay 10ns Receiver propagation delay 25ns High impedance outputs with poweroff Open circuit fail-safefor receiver Extended operating temperature range −40˚Cto 85˚C ESD rating 8kV HBM Drop-in replacementto ADM1485 and LT1485 Availablein 8-pin SOIC Low supply current,ICC= 1mA
Applications Low power RS-485 systems Network hubs, bridges, and routers Pointof sales equipment (ATM, barcode scanners,…) Local area networks (LAN) Integrated service digital network (ISDN) Industrial programmable logic controllers High speed parallel and serial applications Multipoint applications with noisy environment
Typical Application20048801 typical multipoint applicationis showninthe above figure. Terminating resistors,RT,are typically requiredbut only locatedatthetwo endsofthe cable.
Pullupandpull down resistors maybe requiredattheendofthebusto provide failsafe biasing.The biasing resistors provideabiastothe cable whenall
driversarein TRI-STATE,See National Application Note, AN-847for further information.
July 2003
LMS1485
Low
Power
RS-485
Differential
Bus
ransceiver
