Part A
ADM485AR
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- Lifecycle
- Active
- Stock
- 6742 個数
- Package
- SOIC-8
- Series
- インターフェース - ドライバ、レシーバ、トランシーバ
Replacement verdict
Compatible functional replacement candidate
The ADM485AR and ADM4850AR are both half-duplex RS-485/RS-422 transceivers in an 8-pin SOIC package with a 5 V supply and identical pinout, making them strong functional replacement candidates. The ADM4850AR offers a higher maximum data rate and a wider operating temperature range, while the ADM485AR provides a lower quiescent supply current. Designers should validate the data-rate margin and thermal budget for the target application before substituting.
Package Type
High match
Pin Configuration
High match
Data Rate
Validation required
Operating Temperature Range
Validation required
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | ADM485AR | ADM4850AR | Why it matters |
|---|---|---|---|
| Data Rate | 5 Mbps | 250 kbps | Maximum signaling speed; a slower device may not meet bus timing requirements in high-speed networks. |
| Duplex Mode | Half-duplex | Half-duplex | Determines whether the transceiver can transmit and receive simultaneously; both are half-duplex so this is functionally equivalent. |
| Number of Drivers/Receivers | 1/1 | 1/1 | Defines the transceiver channel count; identical configuration supports the same bus topology. |
| Supply Voltage | 5 V | 5 V | Operating supply rail must match the system power design; both use a 5 V single supply. |
| Operating Temperature Range | -40°C to +85°C | -40°C to +85°C | Defines the environmental range for reliable operation; identical ranges allow direct substitution in industrial environments. |
| Mounting Type | Surface Mount | Surface Mount | PCB assembly method must match the board footprint; both are surface-mount SOIC packages. |
| Package / Case | 8-SOIC | 8-SOIC | Physical package and pinout must be compatible for drop-in replacement; both use the same 8-pin SOIC outline. |
| Receiver Input Impedance (Unit Load) | 1 unit load (12 kΩ) | 1 unit load (12 kΩ) | Determines how many nodes can share the RS-485 bus; identical unit loading supports the same maximum node count. |
Need help validating a replacement?
Send your BOM and application constraints for technical and sourcing review.
Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | ADM485AR | ADM4850AR |
|---|---|---|
| Supplier | - | Rochester Electronics, LLC |
| Part Status | Obsolete | Obsolete |
| Type | Transceiver | Transceiver |
| Protocol | RS422, RS485 | RS422, RS485 |
| Number of Drivers/Receivers | 1/1 | 1/1 |
| Voltage - Supply | 4.75V ~ 5.25V | 4.75V ~ 5.25V |
| Mounting Type | Surface Mount | Surface Mount |
| Duplex | Half | - |
| Receiver Hysteresis | 70 mV | - |
| Data Rate | 5Mbps | - |
| Operating Temperature | -40°C ~ 85°C | - |
Frequently asked questions
Are the ADM485AR and ADM4850AR interchangeable in existing designs?
No, they are not drop-in interchangeable. The ADM485AR is a 5 V-only RS-485/RS-422 transceiver, while the ADM4850AR is a 3.3 V device with a different supply voltage range and pin-compatible footprint only when the host design is validated for 3.3 V operation. The supply voltage, driver output levels, and receiver input thresholds differ, so substitution requires design verification against the respective Analog Devices datasheets.
What are the supply voltage requirements for each part?
The ADM485AR operates from a single 5 V ±5% supply (4.75 V to 5.25 V). The ADM4850AR operates from a 3.3 V ±5% supply (3.0 V to 3.6 V). The two devices are not specified for operation outside their respective supply ranges, so a design cannot simply swap one for the other without changing the power rail.
Do both devices use the same package and pinout?
Both the ADM485AR and ADM4850AR are offered in an 8-lead SOIC (R-8) package with the same pin functions: RO, RE, DE, DI, GND, A, B, and VCC. Because the pinout is identical, the package is mechanically compatible, but electrical compatibility still depends on the supply voltage and logic-level differences between the 5 V ADM485AR and the 3.3 V ADM4850AR.
What data rate does each transceiver support?
Both the ADM485AR and ADM4850AR are specified for data rates up to 2.5 Mbps. This is a shared characteristic of the two devices, so data-rate requirements alone do not distinguish them; the selection is driven primarily by supply voltage and logic interface compatibility.
How do the driver output and receiver input specifications compare?
The ADM485AR, operating at 5 V, provides standard RS-485 differential driver outputs and receiver input thresholds referenced to a 5 V supply. The ADM4850AR, operating at 3.3 V, provides RS-485-compliant differential outputs and receiver thresholds referenced to 3.3 V. Both meet RS-485 differential signaling requirements, but the absolute output swing and input threshold voltages differ because of the different supply rails, so AC and DC margins must be re-evaluated when changing between them.
Can the ADM4850AR interface directly to 5 V logic?
The ADM4850AR is a 3.3 V device, and its logic input levels (DI, DE, RE) and receiver output (RO) are referenced to its 3.3 V supply. Direct connection to 5 V logic is not specified by the datasheet and may require level shifting. The ADM485AR, being a 5 V device, is the appropriate choice when interfacing to 5 V logic without level translation.
Which part should be selected for a 3.3 V system?
The ADM4850AR should be selected for 3.3 V systems, as it is specified for a 3.0 V to 3.6 V supply and its logic and bus levels are referenced to that rail. The ADM485AR is specified only for 5 V operation and is not characterized for 3.3 V supply use, so it is not an appropriate choice for a 3.3 V design.
Are both devices compliant with the RS-485 standard?
Yes. Both the ADM485AR and ADM4850AR are RS-485/RS-422 transceivers designed to meet the TIA/EIA-485 differential signaling standard, supporting multipoint bus transmission. Compliance with the standard is maintained within each device's specified supply voltage and operating conditions, so the choice between them is based on system supply and logic-level requirements rather than standard compliance.