Part A
AD8221ARZ
Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 4567 PCS
- Package
- SOIC-8
- Series
- Linear - Amplificadores - Instrumentação, OP Amps, Buffer Amps
Replacement verdict
Compatible functional replacement candidate
The AD8221BR-REEL is a higher-grade variant of the AD8221ARZ instrumentation amplifier, sharing the same pinout, package, and core electrical architecture. The BR grade offers tighter gain error, lower offset voltage, and improved CMRR specifications, making it a functionally compatible and performance-enhanced substitute in most precision signal-conditioning designs, provided the tighter tolerances and cost delta are acceptable.
Package and Pinout
High match
Gain Range and Configuration
High match
Supply Voltage Range
High match
Gain Error and Offset Accuracy
Validation required
Parts at a glance
Part B
AD8221BR-REEL
Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 8526 PCS
- Package
- SOIC-8
- Series
- Linear - Amplificadores - Instrumentação, OP Amps, Buffer Amps
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-REEL | Why it matters |
|---|---|---|---|
| Gain Error (G=1) | 0.02% max | 0.01% max | Lower gain error improves DC accuracy of the instrumentation amplifier in precision measurement chains. |
| Gain Nonlinearity (G=1) | 10 ppm max | 5 ppm max | Better nonlinearity ensures linear signal transfer across the input range, critical for high-resolution data acquisition. |
| Input Offset Voltage | 60 µV max | 25 µV max | Lower offset voltage reduces DC error and drift, improving accuracy in low-level signal amplification. |
| Input Offset Voltage Drift | 0.8 µV/°C max | 0.3 µV/°C max | Lower drift maintains accuracy over temperature, important for industrial and instrumentation applications. |
| Input Bias Current | 1.5 nA max | 0.4 nA max | Lower bias current reduces errors when interfacing with high-impedance sensors. |
| CMRR (G=1, DC to 60 Hz) | 80 dB min | 90 dB min | Higher common-mode rejection suppresses interference and improves signal fidelity in noisy environments. |
| Noise (0.1 Hz to 10 Hz, G=1) | 0.25 µV p-p typ | 0.25 µV p-p typ | Low 1/f noise is essential for precision low-frequency measurements; both grades share the same typical value. |
| Operating Temperature Range | -40°C to +85°C | -40°C to +85°C | Identical temperature range means both parts suit the same environmental conditions. |
| Package / Mounting | 8-Lead SOIC (tube) | 8-Lead SOIC (tape and reel) | Same package and footprint allow drop-in substitution; only the packaging format differs for assembly handling. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | AD8221ARZ | AD8221BR-REEL |
|---|---|---|
| Supplier | - | Analog Devices Inc. |
| 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 primary differences between the AD8221ARZ and AD8221BR-REEL?
Both devices are instrumentation amplifiers from Analog Devices based on the same core design, but they differ in grade and packaging. The AD8221ARZ is supplied in a 8-lead SOIC tube package and is specified with the standard A-grade performance tolerances. The AD8221BR-REEL is the higher-grade B version supplied in a 7-inch reel for automated assembly, offering tighter gain error, offset voltage, and CMRR specifications than the A grade.
Are the AD8221ARZ and AD8221BR-REEL electrically interchangeable in an existing design?
Yes, both parts share the same pinout and function as pin-compatible instrumentation amplifiers in an 8-lead SOIC package. The B grade provides tighter guaranteed specifications, so substituting an AD8221BR-REEL for an AD8221ARZ is generally acceptable where the design meets the B-grade limits, but the reverse substitution requires verifying that the application tolerates the wider A-grade specifications.
What are the gain specifications for these two grades?
Both parts are programmable-gain instrumentation amplifiers set by a single external resistor, with a gain range of 1 to 1000. The AD8221BR-REEL offers tighter guaranteed gain error than the AD8221ARZ, making the B grade preferable for precision applications requiring accurate closed-loop gain.
How do the offset voltage specifications compare between the A and B grades?
The AD8221BR-REEL is specified with a lower maximum input offset voltage than the AD8221ARZ. Designers should consult the respective Analog Devices datasheet grade tables to confirm the exact offset limits, since the B grade is intended for applications where DC precision is critical.
What is the difference in CMRR between the AD8221ARZ and AD8221BR-REEL?
The AD8221BR-REEL guarantees a higher minimum common-mode rejection ratio than the AD8221ARZ. This makes the B grade better suited for precision measurement systems where rejection of common-mode noise and line interference is important.
Why is the AD8221BR-REEL supplied in a reel while the AD8221ARZ is supplied in tubes?
The AD8221BR-REEL is packaged in a 7-inch reel to support high-volume automated pick-and-place assembly lines. The AD8221ARZ is supplied in tubes, which are typically used for lower-volume production, prototyping, and manual assembly. The packaging difference does not affect the electrical function of the device.
Do both parts operate from the same supply voltage range?
Yes, both the AD8221ARZ and AD8221BR-REEL operate from a dual supply range of approximately ±2.3 V to ±18 V, or a single supply of 4.6 V to 36 V, consistent with the AD8221 family datasheet. The supply range is common to both grades.
Which part should be selected for a precision bridge sensor application?
For precision bridge sensor applications, the AD8221BR-REEL is generally the better choice because its tighter offset voltage, gain error, and CMRR specifications reduce measurement uncertainty. The AD8221ARZ remains suitable for less demanding applications where the wider A-grade tolerances are acceptable.