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ADM2485:  High Speed, Isolated RS-485 Transceiver with Integrated Transformer Driver

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 ...More

ADM2485:  High Speed, Isolated RS-485 Transceiver with Integrated Transformer Driver

Product Description

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.

Applications

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

    • Data Sheet, Rev. A, 12/07

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    • 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
    • ESD-Protection: ---
    • Pwr Supply (Vnom): +3 to +5 & ISO +5
    • Data Rate: 16Mbps
    • Full-Half Duplex: Half
    • # of Nodes On Bus: 50
    • Drvr/Rcvr Enable: Yes
    • Fail Safe: Open
    • Isolation V (rms): 2.5 kV
    • Available Packages: SOIC

    Functional Block Diagram for ADM2485

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    Part# Min Pos Supply Pwr Supply (Vnom) Full-Half Duplex ESD-Protection Data Rate # of Nodes On Bus Drvr/Rcvr Enable Fail Safe Isolation V (rms) Available Packages Price* (1000-4999) Protocols
    ADM2482E +3 +3 to +5 & ISO +3 Full, Half 15 kV 16Mbps 256 Yes Open, Short 2.5 kV SOIC $4.66 RS-422, RS-485
    ADM2484E +3 +3 to +5 & ISO +3 Full, Half 15 kV 500kbps 256 Yes Open, Short 5 kV SOIC $3.04 RS-422, RS-485
    ADM2487E +3 +3 to +5 & ISO +3 Full, Half 15 kV 500kbps 256 Yes Open, Short 2.5 kV SOIC $3.64 RS-422, RS-485
    ADM2491E +3 +3 to +5 & ISO +5 Full, Half 8 kV 16Mbps 32 Yes Open 5 kV SOIC $4.76 RS-422, RS-485
    ADM2582E +3 3.3, 5 Full, Half 15 kV 16Mbps 256 Yes Open, Short 2.5 kV SOIC $6.50 RS-422, RS-485
    ADM2587E +3 3.3, 5 Full, Half 15 kV 500kbps 256 Yes Open, Short 2.5 kV SOIC $5.50 RS-422, RS-485
    ADN4668 +3 3.3 --- 15 kV 400Mbps - Yes - - SOIC, SOP $1.16 EIA-644, LVDS
    ADM2490E +2.7 +3 to +5 & ISO +5 Full 8 kV 16Mbps 32 No Open 5 kV SOIC $4.55 RS-422, RS-485
    ADM2483 +2.7 +3 to +5 & ISO +5 Half --- 500kbps 256 Yes Open, Short 2.5 kV SOIC $3.04 RS-485
    ADM2485 +2.7 +3 to +5 & ISO +5 Half --- 16Mbps 50 Yes Open 2.5 kV SOIC $5.57 RS-422, RS-485
    ADM2486 +2.7 +3 to +5 & ISO +5 Half --- 20Mbps 50 Yes Open 2.5 kV SOIC $5.04 RS-485
    ADM3070E +3 3.3 Full 15 kV 250kbps 256 Yes Open, Short --- SOIC $1.62 RS-422, RS-485
    ADM3071E +3 3.3 Full 15 kV 250kbps 256 No Open, Short --- SOIC $1.57 RS-422, RS-485
    ADM3488E +3 3.3 Full 15 kV 250kbps 32 No Open --- SOIC $1.32 RS-422, RS-485
    ADM3488 +3 3.3 Full --- 250kbps 32 No Open --- SOIC $0.91 RS-422, RS-485
    ADM3074E +3 3.3 Full 15 kV 500kbps 256 No Open, Short --- SOIC $1.52 RS-422, RS-485
    ADM3490 +3 3.3 Full --- 10Mbps 32 No Open --- SOIC $1.01 RS-422, RS-485
    ADM3491 +3 3.3 Full --- 10Mbps 32 Yes Open --- DIP, SOIC, SOP $1.37 RS-422, RS-485
    ADM3490E +3 3.3 Full 15 kV 12Mbps 32 No Open --- SOIC $1.37 RS-422, RS-485
    ADM3491E +3 3.3 Full 15 kV 12Mbps 32 Yes Open --- SOIC $1.42 RS-422, RS-485
    ADM3076E +3 3.3 Full 15 kV 16Mbps 256 Yes Open, Short --- SOIC $1.62 RS-422, RS-485
    ADM3077E +3 3.3 Full 15 kV 16Mbps 256 No Open, Short --- SOIC $1.57 RS-422, RS-485
    ADM3072E +3 3.3 Half 15 kV 250kbps 256 Yes Open, Short --- SOIC $1.52 RS-422, RS-485
    ADM3483E +3 3.3 Half 15 kV 250kbps 32 Yes Open --- SOIC $1.32 RS-422, RS-485
    ADM3493 +3 3.3 Half --- 250kbps 256 Yes Open --- SOIC $0.96 RS-422, RS-485
    ADM3483 +3 3.3 Half --- 250kbps 32 Yes Open --- SOIC $0.91 RS-422, RS-485
    ADM3073E +3 3.3 Half 15 kV 500kbps 256 Yes Open, Short --- SOIC $1.62 RS-422, RS-485
    ADM3075E +3 3.3 Half 15 kV 500kbps 256 Yes Open, Short --- SOIC $1.52 RS-422, RS-485
    ADM3486E +3 3.3 Half 15 kV 2.5Mbps 32 Yes Open --- SOIC $1.32 RS-422, RS-485
    ADM3485 +3 3.3 Half --- 10Mbps 32 Yes Open --- SOIC $1.01 RS-422, RS-485
    ADM3485E +3 3.3 Half 15 kV 12Mbps 50 Yes Open --- DIP, SOIC $1.32 RS-422, RS-485
    ADM3078E +3 3.3 Half 15 kV 16Mbps 256 Yes Open, Short --- SOIC $1.55 RS-422, RS-485
    ADM488 +4.5 5 Full --- 250kbps 32 No Open --- DIP, SOIC $1.11 RS-422, RS-485
    ADM489 +4.5 5 Full --- 250kbps 32 Yes Open --- DIP, SOIC, SOP $1.62 RS-422, RS-485
    ADM483E +4.5 5 Half 15 kV 250kbps 32 Yes Open --- DIP, SOIC $1.27 RS-422, RS-485
    ADM4854 +4.75 5 Full --- 115kbps 256 No Open, Short --- SOIC $0.71 RS-422, RS-485
    ADM4855 +4.75 5 Full --- 500kbps 256 No Open, Short --- SOIC $0.71 RS-422, RS-485
    ADM4856 +4.75 5 Full --- 2.5Mbps 256 No Open, Short --- SOIC $0.71 RS-422, RS-485
    ADM4857 +4.75 5 Full --- 10Mbps 256 No Open, Short --- SOIC $0.71 RS-422, RS-485
    ADM4850 +4.75 5 Half --- 115kbps 256 Yes Open, Short --- CSP, MSOP, SOIC $0.71 RS-422, RS-485
    ADM487E +4.75 5 Half 15 kV 250kbps 128 Yes Open --- SOIC $1.32 RS-422, RS-485
    ADM483 +4.75 5 Half --- 250kbps 32 Yes Open --- SOIC $0.67 RS-422, RS-485
    ADM4851 +4.75 5 Half --- 500kbps 256 Yes Open, Short --- CSP, SOIC $0.71 RS-422, RS-485
    ADM1487E +4.75 5 Half 15 kV 2.5Mbps 128 Yes Open --- SOIC $1.32 RS-422, RS-485
    ADM485E +4.75 5 Half 15 kV 2.5Mbps 32 Yes Open --- SOIC $1.32 RS-422, RS-485
    ADM4852 +4.75 5 Half --- 2.5Mbps 256 Yes Open, Short --- CSP, SOIC $0.71 RS-422, RS-485
    ADM485 +4.75 5 Half --- 5Mbps 32 Yes Open --- DIP, SOIC, SOP $1.31 RS-422, RS-485
    ADM4853 +4.75 5 Half --- 10Mbps 256 Yes Open, Short --- CSP, SOIC $0.71 RS-422, RS-485
    ADM1486 +4.75 5 Half --- 30Mbps 50 Yes Open --- SOIC $2.07 RS-422, RS-485
    ADM1485 +4.75 5 Half --- 30Mbps 32 Yes Open --- DIP, SOIC, SOP $1.63 RS-422, RS-485
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    Table Default Sort is Power Supply (Ascending) then Full/Half Duplex Ascending