Part A
AD7891ASZ-1
Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 5058 PCS
- Package
- SOIC-8
- Series
- Acquisição de dados - ADCs-DACs - Objetivo Especial
Replacement verdict
Not a drop-in replacement
The AD7891ASZ-1 and AD7893AR-2 are not drop-in replacements for one another. The AD7891ASZ-1 is an 8-channel, 12-bit simultaneous-sampling data acquisition system in a 44-pin MQFP package, while the AD7893AR-2 is a single-channel, 12-bit successive-approximation ADC in an 8-pin SOIC package. They differ in channel count, package footprint, digital interface, and input configuration, so a direct board-level substitution is not possible without redesign.
Different channel count
Different package footprint
Different digital interface
Different input configuration
Parts at a glance
Part B
AD7893AR-2
Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 4273 PCS
- Package
- SOIC-8
- Series
- Acquisição de dados - Analogo para Convertedores Digitais (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 | AD7893AR-2 | Why it matters |
|---|---|---|---|
| Resolution | 12 bit | 12 bit | Both are 12-bit ADCs, so nominal resolution is equivalent for substitutability. |
| Number of ADC Inputs / Channels | 8 single-ended (multiplexed) | 1 single-ended | The AD7891 provides an 8-channel multiplexer while the AD7893 is single-channel, which fundamentally changes system architecture and channel count. |
| Sampling Rate | 500 kSPS | 117 kSPS | Higher throughput in the AD7891 supports faster acquisition; the AD7893 is slower, affecting timing budgets. |
| Input Type | Single-ended | Single-ended | Both accept single-ended inputs, so signal conditioning topology is compatible. |
| Interface | Parallel | Serial (SPI/QSPI/MICROWIRE compatible) | Parallel vs serial interface requires different host connections and pin count, directly impacting board layout and microcontroller compatibility. |
| Supply Voltage | 5 V | 5 V | Both operate from a 5 V supply, so power rail requirements are compatible. |
| Package / Mounting | 44-Lead MQFP (surface mount) | 8-Lead SOIC (surface mount) | Different package footprints and pin counts prevent direct drop-in replacement without PCB redesign. |
| Operating Temperature Range | -40 °C to +85 °C | -40 °C to +85 °C | Identical industrial temperature ranges mean both suit the same environmental conditions. |
| Reference | Internal reference | External reference | The AD7891 includes an on-chip reference while the AD7893 requires an external reference, affecting BOM count and accuracy design. |
Need help validating a replacement?
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | AD7891ASZ-1 | AD7893AR-2 |
|---|---|---|
| Supplier | - | Analog Devices Inc.,Rochester Electronics, LLC |
| Part Status | Active | Obsolete |
| Number of Bits | - | 12 |
| Sampling Rate(Per Second) | 500k | 117k |
| Number of Inputs | - | 1 |
| Input Type | - | Single Ended |
| Data Interface | Serial, Parallel | SPI |
| 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 |
| 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 AD7893AR-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 AD7893AR-2 is a single-channel, 12-bit successive-approximation ADC with a 6 µs conversion time and a serial interface, housed in an 8-lead SOIC. The AD7891ASZ-1 integrates an input multiplexer and track-and-hold, while the AD7893AR-2 is a standalone ADC requiring an external reference.
Are the AD7891ASZ-1 and AD7893AR-2 pin-compatible or package-compatible?
No. The AD7891ASZ-1 uses a 44-lead MQFP package, while the AD7893AR-2 uses an 8-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 AD7893AR-2 use the same digital interface?
No. The AD7891ASZ-1 provides a parallel digital interface for direct connection to a microprocessor bus. The AD7893AR-2 provides a serial interface for connection to serial ports or microcontrollers. System designers must account for this difference in host interface architecture.
How do the conversion times of the AD7891ASZ-1 and AD7893AR-2 compare?
The AD7891ASZ-1 has a specified conversion time of 1.6 µs typical. The AD7893AR-2 has a specified conversion time of 6 µs. The AD7891ASZ-1 is therefore faster per conversion, though it also includes multiplexer settling considerations when switching channels.
How many analog input channels does each device support?
The AD7891ASZ-1 provides 8 analog input channels through an integrated multiplexer. The AD7893AR-2 provides a single analog input channel. The AD7891ASZ-1 is suited to multi-channel data acquisition, while the AD7893AR-2 is suited to single-channel measurement applications.
Do the AD7891ASZ-1 and AD7893AR-2 have the same resolution and accuracy specifications?
Both devices are 12-bit ADCs. However, their accuracy specifications differ because they are different product families with different architectures and input configurations. Designers should consult the respective manufacturer datasheets for INL, DNL, offset, gain, and total unadjusted error limits before comparing accuracy in a specific application.
Can the AD7893AR-2 directly replace the AD7891ASZ-1 in an existing design?
No. The devices differ in package, pin count, interface type (serial versus parallel), channel count, and conversion time. A direct replacement is not possible without redesigning the PCB, host interface, and channel architecture. Any substitution must be validated against the manufacturer datasheets for the target design.