ADM2587EBRWZ Datasheet, Pinout & Stock: Isolated RS-485/RS-422 Transceiver IC

The ADM2587EBRWZ is Analog Devices’ fully isolated RS-485/RS-422 transceiver that integrates the signal isolator, line driver, receiver, and – crucially – an isolated DC-DC converter in one 20-lead wide-body SOIC. That on-chip isoPower supply means you get a complete signal-and-power isolated RS-485 node without an external isolated DC-DC block. It carries +/-15 kV ESD protection on the bus pins and 2.5 kV rms isolation. This page covers the datasheet specs, the pinout, the ADM2582E vs ADM2587E speed difference, and how to source the part.

ADM2587EBRWZ Key Specs at a Glance

• Function: isolated RS-485/RS-422 transceiver, half- or full-duplex
• Integrated power: isoPower isolated DC-DC on-chip – no external isolated supply needed
• Isolation: 2.5 kV rms (UL 1577, 1 minute); VDE 0884 VIORM 560 V peak
• ESD: +/-15 kV on the RS-485 bus I/O pins
• Data rate: 500 kbps (the faster ADM2582E sibling runs 16 Mbps)
• Supply / bus: single 5 V or 3.3 V; up to 256 nodes; fail-safe receiver; >25 kV/us CMTI
• Package: 20-lead wide-body SOIC (the BRWZ suffix; RoHS)

What Is the ADM2587EBRWZ?

RS-485 networks run across long, electrically noisy plants where grounds drift and surges happen, so galvanic isolation protects the transceiver and the host behind it. The ADM2587E builds that isolation in. Using ADI’s iCoupler technology it combines a three-channel digital isolator, a three-state differential line driver, and a receiver, and then adds isoPower – a transformer-based isolated DC-DC – so the isolated bus side is powered from the logic-side supply with no separate isolated rail.

The result is a single-package, signal-and-power isolated RS-485 node that runs from one 5 V or 3.3 V supply. It is fail-safe on open, short, and idle bus conditions, tolerates more than 25 kV/us of common-mode transient, and includes current limiting and thermal shutdown for bus contention. There is one engineering catch worth stating up front: isoPower moves power by switching at high frequency, so the part is an EMI source and the PCB layout – not the schematic – is what makes it pass radiated-emissions limits.

On the order number: BRW is the 20-lead wide-body SOIC and Z is RoHS. The closest sibling is the ADM2582E, which is the same isolated architecture but rated for 16 Mbps instead of 500 kbps – the single most important choice between the two.

Why isolate RS-485 at all? On a long multidrop bus, the grounds at each node sit at slightly different potentials, and surges, motors, and switching loads inject large common-mode swings. Without isolation those differences flow through the transceiver and can destroy it or the host MCU behind it. Isolation breaks that ground loop so each node references its own clean ground, and integrating the isolated power means the protection does not cost you a separate isolated supply at every node.

ADM2587EBRWZ Specifications (Datasheet Summary)

Parameter	ADM2587EBRWZ
Type	Isolated RS-485/RS-422 transceiver (half/full duplex)
Integrated DC-DC	isoPower isolated supply (no external isolated rail)
Isolation rating	2.5 kV rms (UL 1577); VDE 0884 VIORM 560 V peak
ESD (bus pins)	+/-15 kV
Max data rate	500 kbps
Supply	Single 5 V or 3.3 V
Bus loading	Up to 256 nodes
Receiver	Fail-safe (open/short/idle); +/-200 mV thresholds
Common-mode transient immunity	>25 kV/us
Protection	Current limiting, thermal shutdown
Standards	ANSI/TIA/EIA-485-A-98, ISO 8482:1987(E)
Package	20-lead wide-body SOIC (BRWZ)

ADM2587EBRWZ Pinout and Pin Functions (20-Lead SOIC)

The device splits into a logic side and an isolated bus side across the isolation barrier. By function:

Pin / group	Function
VCC1 / GND1	Logic-side supply (5 V or 3.3 V) and ground; 0.01-0.1 uF decoupling to GND1
RxD (RO)	Receiver output to the host
TxD (DI)	Driver input from the host
DE	Driver enable (active high)
/RE	Receiver enable (active low; high-Z output when disabled)
VISOIN / VISOOUT	isoPower isolated-side power (the integrated DC-DC output)
GND2 (pins 11 & 14)	Isolated bus-side ground
A / B	Receiver differential inputs (bus)
Y / Z	Driver differential outputs (bus); tie A-Y, B-Z for half duplex

ADM2587EBRWZ Applications

The ADM2587E suits any isolated RS-485/RS-422 link on a noisy bus: industrial fieldbus and Modbus RTU networks, factory-automation and PLC I/O, motor-drive communications, building and HVAC automation, and instrumentation that must survive ground-potential differences. Because it carries its own isolated power, it shrinks an isolated RS-485 port to a single device – useful on space-constrained industrial PCB designs. Keeping the lifecycle status of every isolation part in your BOM current avoids surprises when an isolated transceiver goes on allocation.

One practical note for procurement: an isolated transceiver with integrated power like the ADM2587E costs more per unit than a bare RS-485 driver, but it removes an entire isolated DC-DC sub-circuit – transformer, regulator, and the board area and qualification that go with it. On a per-port basis the integrated part is often cheaper once the external isolated supply, its components, and the layout time are counted, which is why it is a common default for isolated industrial ports.

Half-Duplex vs Full-Duplex RS-485 Wiring

The ADM2587E supports both bus topologies, and the wiring differs. In full-duplex RS-485/RS-422 the driver pair (Y, Z) and receiver pair (A, B) run on separate twisted pairs, so a node can transmit and receive at once – useful for point-to-point or master/slave links with continuous traffic. In half-duplex the driver and receiver share one pair (tie Y to A and Z to B), and the bus turns around between transmit and receive using the DE and /RE enable lines.

Two rules keep a half-duplex bus healthy. Terminate both ends of the line in its characteristic impedance, typically 120 ohm, to suppress reflections, and bias the idle bus so the fail-safe receiver reports a defined state when no driver is active. The ADM2587E’s fail-safe inputs cover open, short, and idle conditions, but proper termination and bias are still the designer’s job, not the chip’s.

ADM2587E vs ADM2582E (and Non-Isolated Alternatives)

The most common ADM2587E question is how it differs from the ADM2582E. They are the same isolated, isoPower-equipped family; the difference is bus speed. If you need megabit data rates, the choice is the ADM2582E.

Device	Isolation + power	Max data rate	Notes
ADM2587E	Isolated + isoPower	500 kbps	This part; complete isolated node
ADM2582E	Isolated + isoPower	16 Mbps	Pin-compatible faster sibling
Non-isolated (e.g. ADM485)	None	Varies	Cheaper; needs external isolation if required

A point that catches first-time users: integrating the DC-DC is a real convenience, but it shifts the difficulty to the board. The isoPower transformer switches at high frequency, so passing EN55022 radiated emissions depends on disciplined layout – a ground-plane keep-out under the transformer and surface-mount ferrite beads on the GND2 and VISOOUT nets. ADI publishes specific layout guidance (application notes AN-1349 and AN-0971) precisely because this is where designs succeed or fail EMI testing.

How to Buy the ADM2587EBRWZ (Packaging and Sourcing)

Order the ADM2587EBRWZ for the 20-lead wide-body SOIC in tube or reel to match your line. Isolated transceivers are widely used and well worth verifying when bought on the open market, since relabeled stock appears whenever a popular isolation part tightens. Our components sourcing team supplies the ADM2587E with full traceability, and the wide SOIC assembles cleanly in standard SMT assembly – though the isoPower layout deserves the attention described above.

ADM2587E Design and Assembly Mistakes to Avoid

• Sloppy isoPower layout. Without a ground keep-out under the transformer and ferrite beads on GND2/VISOOUT, the board fails radiated emissions – follow AN-1349 and AN-0971.
• Missing bus termination and fail-safe biasing. Terminate the line in its characteristic impedance (typically 120 ohm) and keep stubs short.
• Confusing the DE and /RE controls, or mis-wiring A/B versus Y/Z for half- versus full-duplex operation.
• Skipping VCC1 decoupling. The datasheet calls for a 0.01-0.1 uF capacitor to GND1.
• Choosing the ADM2587E (500 kbps) for a bus that needs megabit speeds – use the ADM2582E instead.
• Ignoring moisture sensitivity on the wide SOIC; bake per J-STD-033 if reels have been open or stored a long time.

Frequently Asked Questions About the ADM2587EBRWZ

What is the difference between the ADM2587E and ADM2582E?

Bus speed. The ADM2587E is rated for 500 kbps and the ADM2582E for 16 Mbps. Both are signal-and-power isolated with integrated isoPower and +/-15 kV bus ESD; choose by the data rate your network needs.

Does the ADM2587E need an external isolated DC-DC converter?

No. The integrated isoPower converter supplies the isolated bus side from the logic-side rail, which is the main reason to choose this part over a plain isolated transceiver.

What is the isolation rating of the ADM2587E?

2.5 kV rms per UL 1577 (one minute), with VDE 0884 certification at a 560 V peak working voltage. It provides galvanic isolation between the logic and bus sides.

What package is the ADM2587EBRWZ?

A 20-lead wide-body SOIC (ADI package code RW), RoHS-compliant. It is a standard surface-mount part, though the isoPower layout rules still apply.

How many nodes can the ADM2587E bus support?

Up to 256 transceivers on one RS-485 bus, terminated at both ends for half-duplex. The receiver is fail-safe for open, short, and idle line conditions.

Why does my ADM2587E board fail EMI testing?

Almost always the isoPower switching. Add a ground-plane keep-out beneath the transformer and ferrite beads on the GND2 and VISOOUT nets, and follow the ADI layout application notes – the fix is in the PCB, not the part.

Can the ADM2587E run half-duplex and full-duplex?

Both. For full-duplex, use the separate driver (Y, Z) and receiver (A, B) pairs; for half-duplex, tie Y to A and Z to B and turn the bus around with the DE and /RE enables. Terminate both ends at about 120 ohm either way.

Sourcing the ADM2587EBRWZ for Your Isolated Bus

The ADM2587EBRWZ collapses an isolated RS-485 port – isolator, driver, receiver, and isolated power – into one package, as long as the part is genuine and the isoPower layout is right. Send us your part list or BOM and we’ll confirm ADM2587EBRWZ stock, verify authenticity, and quote the assembled board.