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 AD7899AR-3 are not drop-in replacements for one another. Although both are Analog Devices 12-bit successive-approximation ADCs, they differ in channel architecture, analog input configuration, package footprint, and external component requirements, so a direct board-level substitution is not possible without redesign.
Different channel architecture
Different analog input configuration
Different package footprint
Different external component requirements
Parts at a glance
Part B
AD7899AR-3
Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 691 PCS
- Package
- SOIC-28
- 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 | AD7899AR-3 | Why it matters |
|---|---|---|---|
| Resolution | 12 bit | 14 bit | Higher resolution provides finer quantization steps, improving measurement accuracy and dynamic range for precision applications. |
| Number of ADC Inputs / Channels | 8 single-ended (multiplexed) | 1 single-ended | A multiplexed 8-channel input allows monitoring multiple signals with one device, while a single-channel part suits dedicated high-speed conversion of one signal. |
| Sampling Rate | 500 kSPS | 400 kSPS | Maximum throughput determines the highest signal bandwidth that can be digitized without aliasing and affects system timing budgets. |
| Input Type | Single-ended | Single-ended | Input configuration affects how the sensor or signal source must be connected and whether common-mode rejection is available. |
| Interface | Parallel | Parallel | The digital interface must match the host processor or FPGA bus to allow direct connection without glue logic. |
| Supply Voltage | 5 V | 5 V | Supply voltage compatibility ensures the device operates correctly within the system power rails and interfaces with surrounding logic. |
| Package / Mounting | 44-Lead MQFP | 28-Lead SSOP | Package footprint and pin count affect PCB layout, board space, and whether a drop-in replacement is physically 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 | External | Reference configuration determines whether an external voltage reference is required and influences accuracy and drift performance. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | AD7891ASZ-1 | AD7899AR-3 |
|---|---|---|
| Supplier | - | Analog Devices Inc.,Rochester Electronics, LLC |
| Part Status | Active | Obsolete |
| Number of Bits | - | 14 |
| Sampling Rate(Per Second) | 500k | 400k |
| Number of Inputs | - | 1 |
| Input Type | - | Single Ended |
| Data Interface | Serial, Parallel | 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 AD7899AR-3?
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 AD7899AR-3 is a single-channel, 14-bit ADC with a 2.2 µs conversion time and a parallel interface, housed in a 28-lead SOIC. The AD7891ASZ-1 integrates an 8-channel multiplexer, while the AD7899AR-3 is a single-input device with higher resolution.
Do the AD7891ASZ-1 and AD7899AR-3 have the same resolution and accuracy?
No. The AD7891ASZ-1 provides 12-bit resolution, while the AD7899AR-3 provides 14-bit resolution. The AD7899AR-3 therefore offers finer quantization and typically better signal-to-noise performance for a single-channel input, whereas the AD7891ASZ-1 trades resolution for multi-channel capability.
Can the AD7891ASZ-1 and AD7899AR-3 operate from the same analog supply voltage?
Both devices operate from a single +5 V analog supply. The AD7891ASZ-1 also requires a +5 V digital supply, while the AD7899AR-3 uses a +5 V supply for both analog and digital sections. Designers should verify the exact supply and reference configuration against the respective manufacturer datasheets before layout.
Are the AD7891ASZ-1 and AD7899AR-3 pin-compatible or package-compatible?
No. The AD7891ASZ-1 is supplied in a 44-lead MQFP package, while the AD7899AR-3 is supplied in a 28-lead SOIC package. The pin counts, pin functions, and PCB land patterns differ, so these parts are not drop-in replacements for one another.
Which device is better suited for multi-channel data acquisition?
The AD7891ASZ-1 is better suited for multi-channel data acquisition because it integrates an 8-channel input multiplexer with a 12-bit ADC in a single package. The AD7899AR-3 is a single-channel 14-bit ADC and would require external multiplexing to handle multiple inputs.
How do the conversion times of the AD7891ASZ-1 and AD7899AR-3 compare?
The AD7891ASZ-1 has a conversion time of 1.6 µs, while the AD7899AR-3 has a conversion time of 2.2 µs. The AD7891ASZ-1 therefore provides faster per-conversion throughput, though the AD7899AR-3 offers higher resolution per conversion.
Do both the AD7891ASZ-1 and AD7899AR-3 provide a parallel digital interface?
Yes. Both devices provide a parallel digital interface for connection to a microprocessor or DSP. The AD7891ASZ-1 offers a 12-bit parallel output, while the AD7899AR-3 offers a 14-bit parallel output. The interface timing and control signals should be reviewed in the respective datasheets before integration.