Features and Benefits
- Half-duplex, isolated RS-485 transceiver
- Integrated oscillator driver for external transformer
- PROFIBUS® compliant
- Complies with ANSI/TIA/EIA RS-485-A-98 and ISO 8482:1987(E)
- Data rate: 16 Mbps
- 5 V or 3.3 V operation (VDD1)
- High common-mode transient immunity: >25 kV/μs
- Wide-body, 16-lead SOIC package
- 50 nodes on bus
- Isolated DE OUT status output
- Thermal shutdown protection
- Safety and regulatory approvals
- UL recognition: 2500 V rms for 1 minute per UL 1577
- VDE Certificate of Conformity
- DIN V VDE V 0884-10 (VDE V 0884-10):2006-12
- Reinforced insulation, VIORM = 560 V peak
- Operating temperature range: –40°C to +85°C
- Wide-body, 16-lead SOIC package
The ADM2485 differential bus transceiver is an integrated, galvanically isolated component designed for bidirectional data communication on multipoint bus transmission lines. It is designed for balanced transmission lines and complies with ANSI/TIA/EIA RS-485-A-98 and ISO 8482:1987(E).
The device employs Analog Devices, Inc., iCoupler® technology to combine a 3-channel isolator, a three-state differential line driver, and a differential input receiver into a single package. An on-chip oscillator outputs a pair of square waveforms that drive an external transformer to provide isolated power with an external transformer. The logic side of the device can be powered with either a 5 V or a 3.3 V supply, and the bus side is powered with an isolated 5 V supply.
The ADM2485 driver has an active high enable. The driver differential outputs and the receiver differential inputs are connected internally to form a differential input/output port that imposes minimal loading on the bus when the driver is disabled or when VDD1 or VDD2 = 0 V. Also provided is an active high receiver disable that causes the receive output to enter a high impedance state.
The device has current-limiting and thermal shutdown features to protect against output short circuits and situations where bus contention might cause excessive power dissipation. The part is fully specified over the industrial temperature range and is available in a 16-lead, wide-body SOIC package.
- Isolated RS-485/RS-422 interfaces
- PROFIBUS networks
- Industrial field networks
- Multipoint data transmission systems
Product Lifecycle Production
At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.
Evaluation Kits (1)
The ADM2485 evaluation board allows the ADM2485 isolated RS-485 transceiver to be quickly and easily evaluated. The evaluation board allows all of the input and output functions to be exercised without the need for external components. When the ADM2485 is powered by 3.3 V on the logic side, a transformer, TI, is required with a turns ratio of 1:2.2 (DA2304_AL) to step up the 3.3 V to 6 V. This ensures that there is enough headroom for the ADP667 LDO to output a regulated 5 V output (EVAL-ADM2485EB3Z).
If the ADM2485 is powered by 5 V on the logic side, a trans-former, TI, is required with a turns ratio of 1:1.5 (DA2303_AL) so that there is enough headroom for the ADP667 LDO to output a regulated 5 V output (EVAL-ADM2485EB5Z).
Documentation & Resources
AN-1493: Half-Duplex, Isolated RS-485 Interface (Rev. B)11/10/2017
AN-1179: Junction Temperature Calculation for Analog Devices RS-485/RS-422, CAN, and LVDS/M-LVDS Transceivers3/1/2015
AN-0971: Recommendations for Control of Radiated Emissions with isoPower Devices (Rev. C)2/14/2015
AN-960: RS-485/RS-422 Circuit Implementation Guide (Rev. 0)7/28/2008
AN-727: iCoupler® Isolation in RS-485 Applications (Rev. 0)11/1/2006
AN-740: iCoupler® Isolation in RS-232 Applications (Rev. A)11/1/2006
AN-793: ESD/Latch-Up Considerations with iCoupler® Isolation Products (Rev. A)11/1/2006
AN-825: Power Supply Considerations in iCoupler® Isolation Products (Rev. 0)11/1/2006
Options and Solutions for Partitioning Isolated Power in Isolated RS-485 Nodes12/1/2021
Digital Isolators Offer Performance Advantages in Industrial Motor Drive Applications4/1/2012
Inside iCoupler® Technology:ADuM347x PWM Controller and Transformer Driver with Quad-Channel Isolators Design Summary12/10/2010
NAppkin Note: Lowering the Power of the ADuM524x12/10/2010
Reference Designs (1)
ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well. "Zero defects" for shipped products is always our goal.View our quality and reliability program and certifications for more information.
|Part Number||Material Declaration||Reliability Data||Pin/Package Drawing||CAD Symbols, Footprints & 3D Models|
|ADM2485BRWZ||Material Declaration||Reliability Data||16-Lead SOIC Wide|
|ADM2485BRWZ-REEL7||Material Declaration||Reliability Data||16-Lead SOIC Wide|
|Wafer Fabrication Data|
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Pricing displayed is based on 1-piece. The USA list pricing shown is for budgetary use only, shown in United States dollars (FOB USA per unit), and is subject to change. International prices may vary due to local duties, taxes, fees and exchange rates.