Part A
AD7894ARZ-3
Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 3263 PCS
- Package
- SOIC-8
- Series
- Acquisição de dados - Analogo para Convertedores Digitais (ADC)
Replacement verdict
Compatible functional replacement candidate
The AD7894ARZ-3 and AD7892BR-3 are both 14-bit successive-approximation ADCs from Analog Devices, but they differ in input configuration, throughput, and package. The AD7894ARZ-3 offers a single-ended input with a 5 µs conversion time in an 8-lead SOIC, while the AD7892BR-3 provides a faster 1.47 µs conversion in a 24-lead SOIC with additional features. Designers should validate the input topology, sampling rate, and board layout before substituting one for the other.
Resolution
High match
Input Configuration
Not compatible
Package Type
Not compatible
Throughput Rate
Validation required
Parts at a glance
Part B
AD7892BR-3
Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 669 PCS
- Package
- SOIC-24
- 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 | AD7894ARZ-3 | AD7892BR-3 | Why it matters |
|---|---|---|---|
| Resolution | 14 bit | 12 bit | Resolution determines the smallest analog change the ADC can distinguish; a 14-bit part offers finer quantization than a 12-bit part, affecting measurement precision and substitutability. |
| Number of Input Channels | 1 (single-ended) | 2 (single-ended) | Channel count defines how many analog signals can be digitized; a two-channel device can replace a single-channel one only if the extra channel is unused or multiplexing is acceptable. |
| Sampling Rate | 200 kSPS | 500 kSPS | Maximum throughput limits the bandwidth of signals that can be captured; a slower part may not meet timing requirements of a faster system. |
| Input Voltage Range | ±10 V | ±10 V (bipolar) | The analog input span must match the sensor or signal source; mismatched ranges require external conditioning and affect direct substitutability. |
| Interface Type | Serial (SPI/QSPI compatible) | Parallel | The digital interface must match the host controller; serial versus parallel output requires different board routing and firmware, preventing drop-in replacement. |
| Supply Voltage | 5 V | 5 V | Supply voltage compatibility ensures the part operates within the existing power rail; identical values simplify substitution. |
| Package / Mounting | 20-Lead SOIC (surface mount) | 24-Lead SOIC (surface mount) | Package footprint and pin count must match the PCB layout; differing lead counts prevent direct board-level replacement. |
| Operating Temperature Range | -40 °C to +85 °C | -40 °C to +85 °C | Temperature range must cover the application environment; matching ranges indicate equivalent environmental robustness. |
| Power Consumption | Typically 60 mW | Typically 90 mW | Power dissipation affects thermal design and supply sizing; a higher-consumption part may exceed the thermal budget of the original design. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | AD7894ARZ-3 | AD7892BR-3 |
|---|---|---|
| Supplier | - | Analog Devices Inc.,Rochester Electronics, LLC |
| Part Status | Active | Obsolete |
| Number of Bits | 14 | 12 |
| Sampling Rate(Per Second) | 200k | 600k |
| Number of Inputs | 1 | 2 |
| Input Type | Single Ended | Single Ended |
| Data Interface | SPI | SPI, Parallel |
| Configuration | S/H-ADC | S/H-ADC |
| Ratio - S / H: ADC | 1:1 | 1:1 |
| Number of A/D Converters | 1 | 1 |
| Architecture | SAR | SAR |
| Reference Type | External | External, Internal |
| Voltage - Supply, Analog | 5V | 5V |
| Voltage - Supply, Digital | 5V | 5V |
| Operating Temperature | -40°C ~ 85°C | -40°C ~ 85°C |
Frequently asked questions
What are the key differences between the AD7894ARZ-3 and AD7892BR-3?
The AD7894ARZ-3 is a 14-bit successive-approximation ADC with a 5 V single-supply operation and a serial interface, housed in a 24-lead SOIC package. The AD7892BR-3 is a 12-bit ADC with a 3 V supply option and a parallel interface, also in a 24-lead SOIC package. The AD7894ARZ-3 offers higher resolution (14-bit vs 12-bit), while the AD7892BR-3 provides a parallel data bus for faster system integration in some designs.
Are the AD7894ARZ-3 and AD7892BR-3 pin-compatible?
No. Although both are offered in a 24-lead SOIC package, their pin functions differ due to different interface architectures (serial for the AD7894ARZ-3 vs parallel for the AD7892BR-3) and supply configurations. They are not direct drop-in replacements and require separate PCB layouts.
What is the resolution and sampling rate of each device?
The AD7894ARZ-3 provides 14-bit resolution with a maximum throughput rate of 200 kSPS. The AD7892BR-3 provides 12-bit resolution with a maximum throughput rate of 500 kSPS. The AD7892BR-3 therefore offers higher speed at lower resolution, while the AD7894ARZ-3 prioritizes accuracy.
What supply voltages do these ADCs require?
The AD7894ARZ-3 operates from a single 5 V supply. The AD7892BR-3 is specified for 3 V operation (the "-3" suffix denotes the 3 V version). Designs migrating between the two must account for the different supply rails and associated analog input ranges.
What digital interface does each converter use?
The AD7894ARZ-3 uses a serial interface for data output, which reduces pin count and simplifies isolation. The AD7892BR-3 uses a parallel interface, providing simultaneous access to all data bits for high-speed microprocessor or DSP connection. The interface choice is a primary factor in selecting between the two.
Can the AD7894ARZ-3 directly replace the AD7892BR-3 in an existing design?
No. Differences in resolution, supply voltage, interface type, and pinout prevent a direct substitution. A redesign of the digital interface, power supply, and PCB layout would be required, and the system's timing and accuracy requirements must be revalidated against the datasheets.
What are the analog input ranges for these devices?
The AD7894ARZ-3 accepts a bipolar analog input range of ±10 V (with the appropriate reference and configuration per its datasheet). The AD7892BR-3 offers a unipolar 0 V to 2.5 V input range in its 3 V configuration. Engineers must verify the exact input span and reference requirements in the respective manufacturer datasheets before design.