Part A
AD7891ASZ-1
テキサス・インスツルメンツ
- Lifecycle
- Active
- Stock
- 5058 個数
- Package
- SOIC-8
- Series
- データ取得 - ADC/DAC - 特殊用途向け
Replacement verdict
Not a drop-in replacement
The AD7891ASZ-1 and AD7892AR-2 are not drop-in replacements for one another. The AD7891ASZ-1 is an 8-channel multiplexed 12-bit ADC, while the AD7892AR-2 is a single-channel 12-bit ADC with a different analog input architecture and package footprint. Designers must account for differences in channel count, input configuration, package type, and interface timing before considering any substitution.
Different channel count
Different input configuration
Different package type
Different interface timing
Parts at a glance
Part B
AD7892AR-2
テキサス・インスツルメンツ
- Lifecycle
- Active
- Stock
- 9769 個数
- Package
- SOIC-24
- Series
- データ取得 - アナログ/デジタルコンバータ (ADC)
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | AD7891ASZ-1 | AD7892AR-2 | Why it matters |
|---|---|---|---|
| Resolution | 12 bit | 12 bit | Both are 12-bit ADCs, so nominal quantization resolution is equivalent for substitutability. |
| Number of Input Channels | 8 (single-ended, multiplexed) | 2 (single-ended) | The AD7891 provides an 8-channel multiplexer, while the AD7892 offers only 2 channels, affecting system channel count and front-end design. |
| Sampling Rate | 500 kSPS | 500 kSPS | Maximum throughput is the same, so timing budgets for acquisition are comparable. |
| Input Voltage Range | ±10 V (bipolar) | ±10 V (bipolar) | Matching bipolar input range allows similar analog front-end scaling and signal conditioning. |
| Interface Type | Parallel | Parallel | Both use a parallel interface, simplifying digital bus compatibility in existing designs. |
| Supply Voltage | 5 V | 5 V | Identical single 5 V supply simplifies power rail reuse and decoupling requirements. |
| Package | 44-Lead MQFP | 24-Lead SOIC | Different package footprints and pin counts require PCB layout changes and cannot be drop-in substituted. |
| Operating Temperature Range | -40 °C to +85 °C | -40 °C to +85 °C | Equivalent industrial temperature range supports similar environmental deployment. |
| Reference Type | Internal | Internal | Both include an internal reference, reducing external component count and simplifying design. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | AD7891ASZ-1 | AD7892AR-2 |
|---|---|---|
| Supplier | - | Analog Devices Inc.,Rochester Electronics, LLC |
| Part Status | Active | Obsolete |
| Number of Bits | - | 12 |
| Sampling Rate(Per Second) | 500k | 500k |
| Number of Inputs | - | 2 |
| Input Type | - | Single Ended |
| Data Interface | Serial, Parallel | SPI, Parallel |
| Configuration | - | S/H-ADC |
| Ratio - S / H: ADC | - | 1:1 |
| Number of A/D Converters | - | 1 |
| Architecture | - | SAR |
| Reference Type | - | External, Internal |
| Voltage - Supply, Analog | - | 5V |
| Voltage - Supply, Digital | - | 5V |
| Operating Temperature | -40°C ~ 85°C | -40°C ~ 85°C |
| Type | Data Acquisition System (DAS) | - |
| Number of Channels | 8 | - |
| Resolution(Bits) | 12 b | - |
| Voltage Supply Source | Single Supply | - |
| Voltage - Supply | 5V | - |
| Mounting Type | Surface Mount | - |
Frequently asked questions
What are the primary differences between the AD7891ASZ-1 and the AD7892AR-2?
The AD7891ASZ-1 is an 8-channel, 12-bit data acquisition system with a 1.6 µs conversion time and a parallel interface, housed in a 44-lead MQFP. The AD7892AR-2 is a single-channel, 12-bit ADC with a 1.47 µs conversion time and a serial interface, housed in a 24-lead SOIC. The AD7891ASZ-1 integrates an input multiplexer and track-and-hold for multi-channel systems, while the AD7892AR-2 is optimized for single-channel, high-speed serial applications.
Are the AD7891ASZ-1 and AD7892AR-2 pin-compatible or package-compatible?
No. The AD7891ASZ-1 uses a 44-lead MQFP package, while the AD7892AR-2 uses a 24-lead SOIC package. The pin counts, pin functions, and PCB land patterns differ, so they are not drop-in replacements for each other.
Do the AD7891ASZ-1 and AD7892AR-2 have the same digital interface?
No. The AD7891ASZ-1 provides a parallel digital interface for direct connection to a microprocessor bus. The AD7892AR-2 provides a serial digital interface. System designers must account for this difference in the host controller and PCB routing.
How do the input channel configurations of the AD7891ASZ-1 and AD7892AR-2 compare?
The AD7891ASZ-1 is an 8-channel device with an on-chip input multiplexer, allowing multiple analog signals to be digitized by a single ADC. The AD7892AR-2 is a single-channel ADC, so it digitizes one analog input per device. Multi-channel systems using the AD7892AR-2 require external multiplexing.
What are the resolution and conversion time specifications for these two ADCs?
Both devices are 12-bit ADCs. The AD7891ASZ-1 has a conversion time of 1.6 µs, and the AD7892AR-2 has a conversion time of 1.47 µs. These values should be confirmed against the latest Analog Devices datasheets for the specific grade and temperature range.
Can the AD7891ASZ-1 and AD7892AR-2 operate from the same supply voltage?
Both devices are specified for a 5 V supply. Designers should verify the exact supply voltage range, reference requirements, and analog input ranges in the respective Analog Devices datasheets before sharing a supply rail in a mixed design.
Which device is more suitable for a multi-channel data acquisition system?
The AD7891ASZ-1 is more suitable for multi-channel data acquisition because it integrates an 8-channel multiplexer, track-and-hold, and 12-bit ADC in a single package. The AD7892AR-2 is better suited to single-channel applications where a serial interface and smaller package are preferred.
Are the AD7891ASZ-1 and AD7892AR-2 interchangeable in an existing design?
No. Differences in package, pin count, digital interface (parallel versus serial), and channel count (8 versus 1) prevent direct interchangeability. Any substitution requires a full review of the schematic, PCB layout, and host firmware against the Analog Devices datasheets for both parts.