The ADM1485 is a differential line transceiver suitable for high speed bidirectional data communication on multipoint bus transmission lines. It is designed for balanced data transmission and complies with both EIA Standards RS-485 and RS-422. The part contains a differential line driver and a differential line receiver. Both the driver and the receiver may be enabled independently. When disabled, the outputs are tristated. The ADM1485 operates from a single +5 V power supply. Excessive power dissipation caused by bus contention or by output shorting is prevented by a thermal shutdown circuit. This feature forces the driver output into a high impedance state if during fault conditions a significant temperature increase is detected in the internal driver circuitry.
Up to 32 transceivers may be connected simultaneously on a bus, but only one driver should be enabled at any time. It is important therefore that the remaining disabled drivers do not load the bus. To ensure this, the ADM1485 driver features high output impedance when disabled and also when powered down.This minimizes the loading effect when the transceiver is not being utilized. The high impedance driver output is maintained over the entire common-mode voltage range from 7 V to +12 V. The receiver contains a fail safe feature which results in a logic high output state if the inputs are unconnected (floating). The ADM1485 is fabricated on BiCMOS, an advanced mixed technology process combining low power CMOS with fast switching bipolar technology. All inputs and outputs contain protection against ESD; all driver outputs feature high source and sink current capability. An epitaxial layer is used to guard
against latch-up. The ADM1485 features extremely fast switching speeds. Minimal driver propagation delays permit transmission at data rates up to 30 Mbits/s while low skew minimizes EMI interference. The part is fully speci
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Low Power RS-485 SystemsDTE-DCE InterfacePacket SwitchingLocal Area NetworksData ConcentrationData MultiplexersIntegrated Services Digital Network (ISDN)
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Meets EIA RS-485 Standard30 Mb/s Data RateSingle +5 V Supply7 V to +12 V Bus Common-Mode RangeHigh Speed, Low Power BiCMOSThermal Shutdown ProtectionShort Circuit ProtectionZero Skew DriverDriver Propagation Delay: 10 nsReceiver Propagation Delay: 25 nsHigh Z Outputs with Power OffSuperior Upgrade for LTC1485
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VCC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .+7 V
Inputs
Driver Input (DI) . . . . . . . . . . . . . . . .0.3 V to VCC + 0.3 V
Control Inputs (DE, RE) . . . . . . . . . . 0.3 V to VCC + 0.3 V
Receiver Inputs (A, B) . . . . . . . . . . . . . . . . .14 V to +14 V
Outputs
Driver Outputs . . . . . . . . . . . . . . . . . . . . . 14 V to +14 V
Receiver Output . . . . . . . . . . . . . . . 0.5 V to VCC + 0.5 V
Power Dissipation 8-Lead DIP . . . . . . . . . . . . . . . 500 mW
JA, Thermal Impedance . . . . . . . . . . . . . . . . . .+130°C/W
Power Dissipation 8-Lead SOIC . . . . . . . . . .. . . . 450 mW
JA, Thermal Impedance . . . . . . . . . . . . . . . . . +170°C/W
Power Dissipation 8-Lead Cerdip . . . . . . . . . . . . 500 mW
JA, Thermal Impedance . . . . . . . . . . . . . . . . . +125°C/W
Operating Temperature Range
Commercial (J Version) . . . . . . . . . . . . . . . 0°C to +70°C
Industrial (A Version) . . . . . . . . . . . . . . .40°C to +85°C
Storage Temperature Range . . . . . . . . 65°C to +150°C
Lead Temperature (Soldering, 10 sec) . . . . . .. . .+300°C
Vapor Phase (60 sec) . . . . . . . . . . . . . . . . . . . . .+215°C
Infrared (15 sec) . . . . . . . . . . . . . . . . . . . . . . . . .+220°C
Post a Buying Lead
Required Field 
