ADM2485 2.5 kV Signal Isolated, High Speed (16 Mbps), Half Duplex RS-485 Transceiver w/ Transformer Driver

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. Applications Isolated RS-485/RS-422 interfaces PROFIBUS networks Industrial field networks Multipoint data transmission systems

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.

Applications

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

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

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

Interface & Isolation

Isolated RS-485

Data Sheets

Document	note
ADM2485: High Speed, Isolated RS-485 Transceiver with Integrated Transformer Driver Data Sheet (Rev. A)	PDF 580 kB

Application Notes

Document	note
AN-1179: Junction Temperature Calculation for Analog Devices RS-485/RS-422, CAN, and LVDS/M-LVDS Transceivers (Rev. A)	PDF 156.87 K
AN-0971: Recommendations for Control of Radiated Emissions with isoPower Devices (Rev. C)	PDF 406 kB
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
AN-727: iCoupler® Isolation in RS-485 Applications (Rev. 0)	PDF 282 kB
AN-740: iCoupler® Isolation in RS-232 Applications (Rev. 0)	PDF 716 kB
AN-793: ESD/Latch-Up Considerations with iCoupler® Isolation Products (Rev. A)	PDF 246 kB
AN-825: Power Supply Considerations in iCoupler® Isolation Products (Rev. 0)	PDF 181 kB