Part A
AD7894ARZ-3
Analog Equipment GmbH.
- Lifecycle
- Active
- Stock
- 3263 PCS
- Package
- SOIC-8
- Series
- Acquisition de données - Convertisseur analogique - numérique (ADC)
Replacement verdict
Not a drop-in replacement
The AD7894ARZ-3 and AD7890AR-2 are not drop-in replacements for one another. The AD7894ARZ-3 is a single-channel 14-bit successive-approximation ADC offered in a 24-lead SOIC package, while the AD7890AR-2 is an 8-channel 12-bit data acquisition system in a 24-lead PDIP package with an on-chip multiplexer and sample-and-hold. Their differences in resolution, channel count, package footprint, and internal architecture make direct substitution impractical without a full redesign of the surrounding circuitry and board layout.
Different channel count
Different resolution
Different package type
Different internal architecture
Parts at a glance
Part B
AD7890AR-2
Analog Equipment GmbH.
- Lifecycle
- Active
- Stock
- 7872 PCS
- Package
- SOIC-24
- Series
- Acquisition de données - ADC DAC - dédié
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-2 | Why it matters |
|---|---|---|---|
| Resolution (bits) | 14 | 12 | Higher resolution provides finer quantization of the analog input, directly affecting measurement precision and dynamic range. |
| Number of ADC Input Channels | 1 (single-ended) | 8 (multiplexed) | Channel count determines how many analog signals can be digitized; a single-channel part cannot replace a multiplexed multi-channel part without external circuitry. |
| Sampling Rate (max) | 200 kSPS | 117 kSPS | Maximum throughput limits the highest signal frequency that can be captured and constrains system timing budgets. |
| Input Type | Single-ended | Single-ended (multiplexed) | Input configuration affects signal conditioning requirements and whether differential or ground-referenced sources can be directly connected. |
| Supply Voltage | 5 V (single supply) | 5 V (single supply) | Supply voltage compatibility determines whether the part can drop into an existing power rail without level shifting or regulation changes. |
| Digital Interface | Serial (SPI/QSPI compatible) | Serial (SPI/QSPI compatible) | Interface protocol must match the host controller to allow direct communication without glue logic or firmware changes. |
| Package | 8-lead SOIC | 24-lead SOIC | Package footprint and pin count affect PCB layout, board space, and whether a direct drop-in replacement is physically possible. |
| Operating Temperature Range | -40 °C to +85 °C | -40 °C to +85 °C | Temperature range must cover the application environment to ensure specified accuracy and reliability over the operating conditions. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | AD7894ARZ-3 | AD7890AR-2 |
|---|---|---|
| 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-2?
The AD7894ARZ-3 is a 14-bit, single-channel successive-approximation ADC with a serial interface, housed in a 24-lead SOIC package. The AD7890AR-2 is a 12-bit, 8-channel data acquisition system that includes an input multiplexer, track/hold amplifier, and a serial interface, housed in a 24-lead SOIC package. The AD7894 offers higher resolution on a single channel, while the AD7890 provides multi-channel acquisition at lower resolution.
Do the AD7894ARZ-3 and AD7890AR-2 have the same analog input range?
No. The AD7894ARZ-3 is specified for a 0 V to +2.5 V analog input range (the "-3" suffix denotes the 3 V nominal supply version with a 2.5 V reference). The AD7890AR-2 is specified for a 0 V to +2.5 V input range as well, but its input configuration is multiplexed across eight channels. Designers should confirm the exact input span and reference configuration from the respective datasheets before comparing.
Can the AD7894ARZ-3 and AD7890AR-2 operate from the same supply voltage?
The AD7894ARZ-3 is designed for a +5 V supply (the "-3" designation refers to the 3 V reference option, not a 3 V supply). The AD7890AR-2 operates from a +5 V supply. Both are 5 V parts, but the AD7894ARZ-3 uses an on-chip 2.5 V reference, while the AD7890AR-2 requires an external reference. Supply decoupling and reference configuration must be verified per datasheet.
Are the AD7894ARZ-3 and AD7890AR-2 pin-compatible?
No. Although both are 24-lead SOIC devices, their pin functions differ because the AD7890AR-2 integrates an 8-channel multiplexer and additional control pins, while the AD7894ARZ-3 is a single-channel converter. They are not drop-in replacements, and PCB layouts must be designed for each specific part.
Which part is better suited for multi-channel data acquisition?
The AD7890AR-2 is better suited for multi-channel acquisition because it integrates an 8-channel input multiplexer with a track/hold amplifier and a 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.
What serial interface do the AD7894ARZ-3 and AD7890AR-2 use?
Both devices provide a serial digital interface. The AD7894ARZ-3 offers a high-speed serial interface compatible with SPI/QSPI/MICROWIRE and DSP interfaces. The AD7890AR-2 also provides a serial interface for reading conversion results and configuring the multiplexer. Exact timing, word length, and protocol details must be taken from the respective manufacturer datasheets.
How do the resolution and throughput of the AD7894ARZ-3 and AD7890AR-2 compare?
The AD7894ARZ-3 provides 14-bit resolution on a single channel, while the AD7890AR-2 provides 12-bit resolution across eight multiplexed channels. Throughput depends on the serial clock rate and conversion timing specified in each datasheet; the AD7894 generally targets higher resolution per channel, whereas the AD7890 targets multi-channel system integration.
What package and temperature grade do the AD7894ARZ-3 and AD7890AR-2 share?
Both are offered in a 24-lead SOIC package with an industrial temperature range of -40°C to +85°C, as indicated by the "AR" grade suffix. Package outline, lead finish, and moisture sensitivity level should be confirmed against the official Analog Devices datasheets and product pages.