Part A
AD7894ARZ-3
ADI公司
- Lifecycle
- Active
- Stock
- 3263 件
- Package
- SOIC-8
- Series
- 資料獲取-模數轉換器（ADC）
Replacement verdict
Not a drop-in replacement
The AD7894ARZ-3 and AD7890AR-4 are not drop-in replacements for one another. The AD7894ARZ-3 is a single-channel 14-bit successive-approximation ADC in a 24-lead SOIC package, while the AD7890AR-4 is an 8-channel 12-bit data-acquisition system in a 24-lead SOIC package with an on-chip multiplexer and reference. Although both share a similar SOIC-24 footprint and 5 V supply, they differ fundamentally in channel count, resolution, and internal architecture, so a direct board-level substitution is not feasible without redesign.
Different channel count
Different resolution
Different internal architecture
Different input configuration
Parts at a glance
Part B
AD7890AR-4
ADI公司
- Lifecycle
- Active
- Stock
- 6793 件
- Package
- SOIC-24
- Series
- 資料獲取-ADC DAC-專用
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | AD7894ARZ-3 | AD7890AR-4 | Why it matters |
|---|---|---|---|
| Resolution | 14 bit | 12 bit | Higher resolution provides finer quantization steps, which directly affects measurement accuracy and dynamic range in the application. |
| Number of ADC Inputs / Channels | 1 (single-ended) | 8 (single-ended, multiplexed) | The channel count determines how many analog signals can be digitized; a multiplexed 8-channel part supports multi-signal systems while a single-channel part suits one-signal designs. |
| Sampling Rate | 200 kSPS | 117 kSPS | Maximum throughput limits the bandwidth of signals that can be captured and constrains system update rates. |
| Input Voltage Range | ±2.5 V (bipolar) | 0 V to +4.096 V (unipolar) | The input span must match the sensor or signal source; bipolar vs unipolar ranges affect signal conditioning and offset requirements. |
| Supply Voltage | 5 V (single supply) | 5 V (single supply) | Supply compatibility determines whether the part can drop into an existing power rail without additional regulation. |
| Interface Type | Serial (SPI/QSPI compatible) | Serial (SPI/QSPI compatible) | The digital interface must match the host controller; serial interfaces reduce pin count and simplify isolation. |
| Package / Mounting | 20-lead SOIC (surface mount) | 24-lead SOIC (surface mount) | Package footprint and pin count affect PCB layout, board space, and whether a direct drop-in replacement is possible. |
| Operating Temperature Range | -40 °C to +85 °C | -40 °C to +85 °C | The temperature range must cover the application environment to guarantee specified performance and reliability. |
| Reference Type | External reference | External reference | Reference configuration affects accuracy, drift, and whether an additional reference IC is required in the design. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | AD7894ARZ-3 | AD7890AR-4 |
|---|---|---|
| Supplier | - | Analog Devices Inc.,Rochester Electronics, LLC |
| Part Status | Active | Obsolete |
| Type | - | Data Acquisition System (DAS) |
| Number of Channels | - | 8 |
| Resolution(Bits) | - | 12 b |
| Sampling Rate(Per Second) | 200k | 117k |
| Data Interface | SPI | SPI |
| Voltage Supply Source | - | Single Supply |
| Voltage - Supply | - | 5V |
| Operating Temperature | -40°C ~ 85°C | -40°C ~ 85°C |
| Mounting Type | - | Surface Mount |
| Number of Bits | 14 | - |
| Number of Inputs | 1 | - |
| Input Type | Single Ended | - |
| Configuration | S/H-ADC | - |
| Ratio - S / H: ADC | 1:1 | - |
| Number of A/D Converters | 1 | - |
| Architecture | SAR | - |
| Reference Type | External | - |
| Voltage - Supply, Analog | 5V | - |
| Voltage - Supply, Digital | 5V | - |
Frequently asked questions
What are the key architectural differences between the AD7894ARZ-3 and AD7890AR-4?
The AD7894ARZ-3 is a single-channel, 14-bit successive-approximation ADC with a serial interface, housed in a 24-lead SOIC package. The AD7890AR-4 is an 8-channel, 12-bit data acquisition system that includes an input multiplexer, track/hold amplifier, and a serial interface, housed in a 24-lead SOIC package. The AD7894 provides higher resolution on a single channel, while the AD7890 integrates an 8-channel multiplexer for multi-channel acquisition at 12-bit resolution.
Do the AD7894ARZ-3 and AD7890AR-4 have compatible package footprints?
Both devices are offered in a 24-lead SOIC package, but the pin functions and internal signal assignments differ because the AD7890AR-4 integrates an 8-channel multiplexer and the AD7894ARZ-3 is a single-channel converter. The packages are not pin-for-pin interchangeable, and the PCB land pattern and pinout must be verified against the respective manufacturer datasheets before any layout substitution.
How do the resolution and throughput of the AD7894ARZ-3 and AD7890AR-4 compare?
The AD7894ARZ-3 provides 14-bit resolution on a single input channel. The AD7890AR-4 provides 12-bit resolution across eight input channels via its integrated multiplexer. The AD7894 offers higher resolution for single-channel applications, while the AD7890 provides multi-channel capability at 12-bit resolution. Throughput and conversion timing should be confirmed from the respective Analog Devices datasheets for the specific grade and operating conditions.
Can the AD7894ARZ-3 and AD7890AR-4 operate from the same analog supply voltage?
The AD7894ARZ-3 is specified for 5 V operation. The AD7890AR-4 is also specified for 5 V operation. Both devices are 5 V single-supply ADCs, but the exact supply tolerance, reference requirements, and input voltage ranges should be verified from the respective Analog Devices datasheets before sharing a common supply rail in a design.
What input signal range does each device support?
The AD7894ARZ-3 accepts a bipolar analog input range of ±10 V. The AD7890AR-4 accepts a unipolar analog input range of 0 V to +2.5 V (with a 2.5 V reference). The input ranges are not equivalent, so signal conditioning and reference configuration must be designed separately for each device. Confirm the exact input range and reference configuration from the Analog Devices datasheets for the specific grade.
Are the AD7894ARZ-3 and AD7890AR-4 drop-in replacements for each other?
No. The AD7894ARZ-3 is a single-channel 14-bit ADC, while the AD7890AR-4 is an 8-channel 12-bit data acquisition system. They differ in resolution, channel count, input range, and pinout, so neither device can be used as a drop-in replacement for the other without redesigning the signal chain, reference, and digital interface. Any substitution must be validated against the manufacturer datasheets.
What serial interface do the AD7894ARZ-3 and AD7890AR-4 use?
Both devices provide a serial digital interface for connection to microcontrollers and DSPs. The AD7894ARZ-3 uses a serial interface for outputting conversion results. The AD7890AR-4 also uses a serial interface and additionally requires control signals for channel selection through its multiplexer. The exact interface timing, clock requirements, and control signal definitions should be verified from the respective Analog Devices datasheets.
Which device is better suited for multi-channel data acquisition?
The AD7890AR-4 is better suited for multi-channel data acquisition because it integrates an 8-channel input multiplexer, track/hold amplifier, and 12-bit ADC in a single package. The AD7894ARZ-3 is a single-channel 14-bit ADC and would require external multiplexing to handle multiple channels. The choice depends on whether higher resolution on one channel or integrated multi-channel capability is required.