The ADM485 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 ADM485 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 ADM485 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 form -7V 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 ADM485 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 EDS; all diver outputs feature high source and sink current capability. An epitaxial layer is used to guard against latch-up.
The ADM485 features extremely fast switching speeds. Minimal driver propagation delays permit transmission at data rates up to 5 Mbits/s while low skew minimizes EMI interference.
The part is fully specified over the commercial and industrial temperature range and is available in an 8-pin DIL/SOIC packages.
Features and Benefits
| Interface & IsolationBuilding Technology
ADM485 IBIS Model
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| Document | note |
| ADM485: 5 V Low Power EIA RS-485 Transceiver Data Sheet (Rev. F) | PDF 254 kB |
| Document | note |
| AN-1176: Component Footprints and Symbols in the Binary .Bxl File Format (Rev. 0) | PDF 671 kB |
| AN-960: RS-485/RS-422 Circuit Implementation Guide (Rev. 0) | PDF 245 kB |
| Part Number | Package | Packing Qty | Temp Range | Price 100-499 | Price 1000+ | RoHS |
|---|---|---|---|---|---|---|
| ADM485AN Last Time Buy | 8 ld PDIP | OTH 50 | 0 | 0 | N | |
| ADM485ANZ Production | 8 ld PDIP | OTH 50 | -40 to 85C | 2.12 | 1.91 | Y |
| ADM485AR Production | 8 ld SOIC | OTH 98 | -40 to 85C | 2.24 | 2.01 | N |
| ADM485AR-REEL Contact ADI | 8 ld SOIC | REEL 2500 | 0 | 2.01 | N | |
| ADM485ARM Obsolete | 8 ld MSOP | OTH 50 | 0 | 0 | N | |
| ADM485ARM-REEL Obsolete | 8 ld MSOP | REEL 3000 | 0 | 0 | N | |
| ADM485ARMZ Production | 8 ld MSOP | OTH 50 | -40 to 85C | 2.01 | 1.82 | Y |
| ADM485ARMZ-REEL Production | 8 ld MSOP | REEL 3000 | -40 to 85C | 0 | 1.82 | Y |
| ADM485ARMZ-REEL7 Production | 8 ld MSOP | REEL 1000 | -40 to 85C | 0 | 1.82 | Y |
| ADM485ARZ Production | 8 ld SOIC | OTH 98 | -40 to 85C | 1.66 | 1.5 | Y |
| ADM485ARZ-REEL Production | 8 ld SOIC | REEL 2500 | -40 to 85C | 0 | 1.5 | Y |
| ADM485JN Obsolete | 8 ld PDIP | OTH 50 | 0 | 0 | N | |
| ADM485JNZ Production | 8 ld PDIP | OTH 50 | 0 to 70C | 1.61 | 1.44 | Y |
| ADM485JR Obsolete | 8 ld SOIC | OTH 98 | 0 | 0 | N | |
| ADM485JR-REEL Obsolete | 8 ld SOIC | REEL 2500 | 0 | 0 | N | |
| ADM485JR-REEL7 Obsolete | 8 ld SOIC | REEL 1000 | 0 | 0 | N | |
| ADM485JRZ Production | 8 ld SOIC | OTH 98 | 0 to 70C | 1.46 | 1.31 | Y |
| ADM485JRZ-REEL Production | 8 ld SOIC | REEL 2500 | 0 to 70C | 0 | 1.31 | Y |
| ADM485JRZ-REEL7 Production | 8 ld SOIC | REEL 1000 | 0 to 70C | 0 | 1.31 | Y |
| Part Number | Description | Price | RoHS |
|---|---|---|---|
| EVAL-RS485HDEBZ | Standard Half-Duplex RS-485 Evaluation Board | 30 | Y |
