Part A
ADM4851ARZ
Компания Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 4442 ПКС
- Package
- SOIC-8
- Series
- Интерфейс - драйверы, приемники, передатчики
Replacement verdict
Compatible functional replacement candidate
The ADM4852ARZ and ADM4851ARZ are functionally compatible RS-485/RS-422 transceivers from the same Analog Devices family, sharing an identical 8-lead SOIC footprint, supply voltage range, and data rate. The primary distinction lies in their receiver input impedance and fail-safe behavior, so the ADM4851ARZ can serve as a functional substitute for the ADM4852ARZ in most designs, provided the receiver loading and fail-safe requirements of the target application are validated against the specific bus configuration.
Package Type
High match
Supply Voltage Range
High match
Data Rate
High match
Receiver Input Impedance
Validation required
Parts at a glance
Part B
ADM4852ARZ
Компания Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 4726 ПКС
- Package
- SOIC-8
- Series
- Интерфейс - драйверы, приемники, передатчики
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | ADM4852ARZ | ADM4851ARZ | Why it matters |
|---|---|---|---|
| Data Rate | 2.5 Mbps | 500 kbps | Maximum signaling speed; determines whether the part can support the required bus bandwidth in the target application. |
| Duplex Mode | Half-duplex | Half-duplex | Defines whether transmit and receive share the same differential pair; must match the bus topology of the system. |
| Number of Drivers/Receivers | 1/1 | 1/1 | Indicates the transceiver channel count; must align with the number of bus lines to be driven and monitored. |
| Supply Voltage | 5 V | 5 V | Operating supply rail; must match the system power architecture for direct substitution. |
| Operating Temperature Range | -40°C to +85°C | -40°C to +85°C | Environmental rating; ensures reliable operation across the intended industrial temperature envelope. |
| Package / Mounting | 8-SOIC (Surface Mount) | 8-SOIC (Surface Mount) | Footprint and assembly compatibility; identical packages allow drop-in board replacement without layout changes. |
| Fail-Safe Receiver | Yes | Yes | Guarantees a defined logic output when the bus is idle or open, preventing spurious data in multi-node networks. |
| ESD Protection (Bus Pins) | ±15 kV (HBM) | ±15 kV (HBM) | Robustness against electrostatic discharge on the differential bus; affects field reliability and system protection requirements. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | ADM4851ARZ | ADM4852ARZ |
|---|---|---|
| Part Status | Active | Active |
| Type | Transceiver | Transceiver |
| Protocol | RS422, RS485 | RS422, RS485 |
| Number of Drivers/Receivers | 1/1 | 1/1 |
| Duplex | Half | Half |
| Receiver Hysteresis | 20 mV | 20 mV |
| Data Rate | 500kbps | 2.5Mbps |
| Voltage - Supply | 4.75V ~ 5.25V | 4.75V ~ 5.25V |
| Operating Temperature | -40°C ~ 85°C | -40°C ~ 85°C |
| Mounting Type | Surface Mount | Surface Mount |
Frequently asked questions
What are the key differences between the ADM4852ARZ and ADM4851ARZ?
Both are 5 V, half-duplex RS-485/RS-422 transceivers in 8-lead SOIC (R-8) packages from Analog Devices. The primary difference is the receiver input impedance and thus the allowable number of nodes on the bus: the ADM4851ARZ is a standard full-load receiver (1 unit load, 32 nodes), while the ADM4852ARZ is a low-load receiver (1/8 unit load, 256 nodes). The ADM4852ARZ also specifies a lower receiver input current, enabling higher node counts.
Are the ADM4852ARZ and ADM4851ARZ pin-compatible?
Yes. Both devices use the same 8-lead SOIC (R-8) package and the same pinout: RO, /RE, DE, DI, GND, A, B, and VCC. This allows the ADM4852ARZ to be used as a drop-in replacement for the ADM4851ARZ in existing layouts, provided the increased node count and receiver input characteristics are acceptable for the bus design.
How many nodes can each device support on an RS-485 bus?
The ADM4851ARZ is a 1-unit-load device and supports up to 32 nodes on a standard RS-485 bus. The ADM4852ARZ is a 1/8-unit-load device and supports up to 256 nodes. The node count is determined by the receiver input impedance; the ADM4852ARZ presents a higher input impedance, allowing more transceivers to share the same bus.
Do both parts support the same data rate?
Yes. Both the ADM4851ARZ and ADM4852ARZ are specified for data rates up to 2.5 Mbps. The maximum data rate is limited by the driver slew rate and cable characteristics, and both devices share the same driver/receiver architecture in this regard.
What is the difference in receiver input current between the two devices?
The ADM4851ARZ (1 unit load) has a higher receiver input current, consistent with a standard RS-485 load. The ADM4852ARZ (1/8 unit load) has a lower receiver input current, approximately one-eighth that of a full-load receiver, which is what enables the 256-node capability. Designers should verify the exact input current specification in the respective Analog Devices datasheets for worst-case bus loading calculations.
Can the ADM4852ARZ directly replace the ADM4851ARZ in an existing design?
In most cases yes, because the package, pinout, supply voltage (5 V), and data rate (2.5 Mbps) are the same. However, the replacement should be validated against the bus design: the ADM4852ARZ's lower receiver input current and higher node count change bus loading, and termination and fail-safe biasing should be rechecked. Always confirm against the latest Analog Devices datasheets before substitution.
Do both devices operate from a single 5 V supply?
Yes. Both the ADM4851ARZ and ADM4852ARZ are specified for a single 5 V supply (nominally 5 V ±5%). They are not 3.3 V devices, so they should not be used in 3.3 V-only systems without level shifting or a suitable 5 V rail.
Are both parts half-duplex transceivers?
Yes. Both the ADM4851ARZ and ADM4852ARZ are half-duplex RS-485/RS-422 transceivers, meaning they share the same differential pair (A and B) for transmit and receive and use the /RE and DE pins to control direction. Neither device provides full-duplex operation.