Part A
AD8221ARZ
Công ty Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 4567 PCS
- Package
- SOIC-8
- Series
- Linear - Amplifiers - Instrumentation, OP Amps, Buffer Amps
Replacement verdict
Compatible functional replacement candidate
The AD8221BR is a higher-grade variant of the AD8221ARZ instrumentation amplifier, sharing the same pinout, package, and core architecture while offering tighter gain and offset specifications. It is a viable functional replacement candidate where improved DC precision is beneficial, though designers should validate gain error and offset drift against their application requirements before substituting.
Package Type
High match
Pin Configuration
High match
Gain Range
High match
Gain Error and Offset Drift
Validation required
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | AD8221ARZ | AD8221BR | Why it matters |
|---|---|---|---|
| Gain Error (G=1, max) | 0.1% | 0.02% | Lower gain error improves absolute accuracy of the amplified signal, which is critical for precision measurement and bridge transducer applications. |
| Input Offset Voltage (max) | 60 µV | 25 µV | Offset voltage directly adds DC error to the measured signal; a lower offset enables more accurate low-level signal amplification. |
| Input Offset Voltage Drift (max) | 0.8 µV/°C | 0.3 µV/°C | Drift determines offset stability over temperature, affecting accuracy in environments with varying thermal conditions. |
| Input Bias Current (max) | 1.5 nA | 1.0 nA | Bias current interacts with source impedance to create offset errors; lower bias current supports higher-impedance sensor interfaces. |
| CMRR (G=1, min) | 80 dB | 90 dB | Common-mode rejection ratio determines how well the amplifier rejects unwanted common-mode noise, essential in noisy industrial environments. |
| Noise (RTI, 1 kHz, typ) | 8 nV/√Hz | 8 nV/√Hz | Input-referred noise sets the minimum detectable signal; both grades share similar noise performance, so noise is not a differentiator. |
| Gain Bandwidth Product | 825 kHz | 825 kHz | Bandwidth limits the maximum signal frequency that can be amplified with acceptable gain; identical values mean equivalent AC response. |
| Operating Temperature Range | -40 to +85 °C | -40 to +85 °C | The temperature range defines the environments in which the part can be reliably operated; identical ranges mean equivalent environmental suitability. |
| Supply Voltage Range | ±2.3 V to ±18 V | ±2.3 V to ±18 V | Supply range determines compatibility with the system power rails; identical ranges mean the parts are interchangeable in the same supply design. |
| Package | 8-Lead SOIC | 8-Lead SOIC | Package compatibility ensures the parts are drop-in replacements on the same PCB footprint. |
Need help validating a replacement?
Send your BOM and application constraints for technical and sourcing review.
Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | AD8221ARZ | AD8221BR |
|---|---|---|
| Supplier | - | Analog Devices Inc.,Rochester Electronics, LLC |
| Part Status | Active | Obsolete |
| Amplifier Type | Instrumentation | Instrumentation |
| Number of Circuits | 1 | 1 |
| Slew Rate | 2V/µs | 2V/µs |
| -3 dB Bandwidth | 825 kHz | 825 kHz |
| Current - Input Bias | 500 pA | 200 pA |
| Voltage - Input Offset | 60 µV | 25 µV |
| Supply Current | 900µA | 900µA |
| Current - Output / Channel | 18 mA | 18 mA |
| Voltage - Supply Span(Min) | 4.6 V | 4.6 V |
| Voltage - Supply Span(Max) | 36 V | 36 V |
| Operating Temperature | -40°C ~ 85°C | -40°C ~ 85°C |
| Mounting Type | Surface Mount | Surface Mount |
Frequently asked questions
What are the main differences between the AD8221ARZ and AD8221BR?
Both are AD8221 instrumentation amplifiers in the same 8-lead SOIC package, but they differ in grade and specified performance. The AD8221BR is the higher-grade version with tighter guaranteed specifications, notably lower gain error, tighter gain nonlinearity, and lower offset voltage and offset drift compared with the AD8221ARZ. The AD8221ARZ is the standard grade. Both share the same pinout and function, so the choice depends on the accuracy required by the application.
Are the AD8221ARZ and AD8221BR pin-compatible and package-compatible?
Yes. Both devices are offered in the same 8-lead SOIC (R-8) package with identical pin assignments, so they are pin-to-pin and footprint compatible. This allows a board designed for one grade to be populated with the other without layout changes, provided the electrical specifications of the selected grade meet the design requirements.
Can the AD8221ARZ be replaced directly by the AD8221BR on an existing PCB?
Physically, yes, because both use the same 8-lead SOIC package and pinout. Electrically, the AD8221BR is a higher-grade part with tighter specifications, so substituting it for the AD8221ARZ is generally acceptable from a performance standpoint. The reverse substitution (BR to ARZ) requires verifying that the ARZ grade's looser specifications still satisfy the design margins.
How do the gain specifications differ between the AD8221ARZ and AD8221BR?
The AD8221 gain is set by a single external resistor, and both grades use the same gain equation. The AD8221BR is specified with tighter gain error and gain nonlinearity limits than the AD8221ARZ, making the BR grade preferable for precision applications requiring accurate closed-loop gain. Designers should consult the respective datasheet grade tables for the exact guaranteed limits at the gain of interest.
Do the AD8221ARZ and AD8221BR have the same supply voltage and operating temperature range?
Both grades are specified for the same supply voltage range and the same operating temperature range as defined in the AD8221 datasheet. The difference between the grades is in guaranteed accuracy parameters rather than in supply or temperature ratings. Always confirm the specific grade's datasheet table for the exact limits over the full temperature range.
Which grade should be selected for a precision low-drift instrumentation amplifier design?
For precision, low-drift designs, the AD8221BR is the appropriate choice because it offers tighter guaranteed offset voltage, offset voltage drift, gain error, and gain nonlinearity than the AD8221ARZ. The AD8221ARZ remains suitable for applications where the standard-grade limits provide adequate margin. Selection should be based on the error budget of the specific signal chain.
Are the AD8221ARZ and AD8221BR functionally identical apart from grade specifications?
Yes. Both are the same AD8221 instrumentation amplifier core with identical functionality, pinout, package, and gain-setting method using an external resistor. The distinction is the guaranteed specification grade: the BR grade is tested and guaranteed to tighter limits than the ARZ grade. No functional or architectural difference exists between the two grades.