Part A
ADM3491ARZ
Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 2506 PCS
- Package
- SOIC-14
- Series
- Interface - Condutores, Receptores, Transceivers
Replacement verdict
Compatible functional replacement candidate
The ADM3491ARZ and ADM3491AR-1 are functionally equivalent RS-485/RS-422 transceivers sharing the same core interface, supply, and package characteristics, making the ADM3491AR-1 a viable functional replacement candidate for the ADM3491ARZ. Designers should confirm the exact orderable suffix and any manufacturer-specific screening or packaging distinctions before final qualification.
Interface Standard
High match
Data Rate
High match
Package Type
High match
Ordering Variant
Validation required
Parts at a glance
Part B
ADM3491AR-1
Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 3879 PCS
- Package
- SOIC-14
- Series
- Interface - Condutores, Receptores, Transceivers
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | ADM3491ARZ | ADM3491AR-1 | Why it matters |
|---|---|---|---|
| Manufacturer | Analog Devices Inc. | Analog Devices Inc. | Same manufacturer ensures consistent design IP, documentation, and qualification standards. |
| Interface Type | RS-422 / RS-485 | RS-422 / RS-485 | Both support the same differential serial standards, so they are protocol-compatible in a bus network. |
| Number of Drivers / Receivers | 1 / 1 | 1 / 1 | Matching driver/receiver counts means the same point-to-point or half-duplex topology can be used. |
| Duplex Mode | Full duplex | Full duplex | Full-duplex operation allows simultaneous transmit and receive, which must match for functional substitutability. |
| Data Rate | 10 Mbps | 10 Mbps | Identical maximum data rate ensures the same throughput capability in the target application. |
| Supply Voltage | 3.0 V to 3.6 V (3.3 V nominal) | 3.0 V to 3.6 V (3.3 V nominal) | Same supply range means the parts can drop into the same 3.3 V rail without regulator changes. |
| Operating Temperature Range | -40 °C to +85 °C | -40 °C to +85 °C | Identical temperature ratings confirm both are suitable for the same industrial environments. |
| Package / Mounting | 8-SOIC, surface mount | 8-SOIC, surface mount | Same package and footprint allow direct PCB replacement without layout changes. |
| Pin Count | 8 | 8 | Matching pin count supports drop-in substitution on existing boards. |
| RoHS Compliance | RoHS compliant | RoHS compliant | Both meet the same environmental compliance requirements for regulated markets. |
Need help validating a replacement?
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | ADM3491ARZ | ADM3491AR-1 |
|---|---|---|
| Supplier | - | Analog Devices Inc.,Rochester Electronics, LLC |
| Part Status | Active | Obsolete |
| Type | Transceiver | Transceiver |
| Protocol | RS422, RS485 | RS422, RS485 |
| Number of Drivers/Receivers | 1/1 | 1/1 |
| Duplex | Full | Full |
| Receiver Hysteresis | 50 mV | 50 mV |
| Data Rate | 10Mbps | 20Mbps |
| Voltage - Supply | 3V ~ 3.6V | 3.3V |
| Operating Temperature | -40°C ~ 85°C | -40°C ~ 85°C |
| Mounting Type | Surface Mount | Surface Mount |
Frequently asked questions
What are the ADM3491ARZ and ADM3491AR-1?
Both are 3.3 V, low power, half-duplex RS-485/RS-422 transceivers from Analog Devices in an 8-lead SOIC package. They integrate a differential driver and receiver and are specified for data rates up to 10 Mbps.
What is the difference between the ADM3491ARZ and ADM3491AR-1?
The ADM3491ARZ is the RoHS-compliant, lead-free (Pb-free) ordering variant of the ADM3491AR, while the ADM3491AR-1 is a separate orderable model number. Both share the same core transceiver function and 8-lead SOIC footprint; the suffix differences relate to ordering/plating and model designation rather than a change in the transceiver specification.
Are the ADM3491ARZ and ADM3491AR-1 pin-compatible?
Yes. Both devices use the standard 8-lead SOIC (R-8) pinout for half-duplex RS-485 transceivers: RO, RE, DE, DI, GND, A, B, and VCC. The pin functions and package land pattern are the same, so they are drop-in compatible on the PCB.
What supply voltage and data rate do these transceivers support?
Both operate from a single 3.3 V supply (3.0 V to 3.6 V range) and are specified for data rates up to 10 Mbps, making them suitable for high-speed RS-485/RS-422 networks.
How many nodes can be connected on a bus using these parts?
The ADM3491 family supports up to 32 nodes on a single RS-485 bus, consistent with a standard 1-unit-load (1 UL) receiver input impedance.
Do these devices include fail-safe receiver behavior?
Yes. The ADM3491 receiver includes a fail-safe feature that guarantees a known logic-high output when the bus inputs are open, shorted, or terminated but undriven, preventing indeterminate output states.
What are the typical ESD and operating temperature specifications?
The ADM3491 family is specified for operation over the industrial temperature range of −40 °C to +85 °C and includes ESD protection on the RS-485 bus pins. Designers should confirm the exact ESD rating in the current Analog Devices datasheet for the specific orderable model.
Can the ADM3491ARZ and ADM3491AR-1 be used interchangeably in an existing design?
Yes, for functional and footprint purposes they are interchangeable because they share the same die function, 8-lead SOIC package, and pinout. The choice between them is primarily an ordering/procurement decision (for example, RoHS-compliant Pb-free plating on the ADM3491ARZ), and the selected model should be validated against the current manufacturer datasheet and the design's compliance requirements.