Part A
AD8226ARZ-R7
Analog Equipment GmbH.
- Lifecycle
- Active
- Stock
- 5908 PCS
- Package
- SOIC-8
- Series
- Amplificateurs linéaires - instruments, amplificateurs opérationnels, amplificateurs tampons
Replacement verdict
Compatible functional replacement candidate
The AD8226ARZ-R7 and AD8221BR are both precision instrumentation amplifiers from Analog Devices in the same SOIC-8 package, sharing a common pinout and comparable supply and gain specifications. However, they differ in input architecture and bandwidth, so the AD8221BR can serve as a functional replacement candidate for the AD8226ARZ-R7 only after validating application-specific requirements such as input bias current, noise, and bandwidth.
Package Type
High match
Supply Voltage Range
High match
Input Architecture
Validation required
Bandwidth and Noise
Validation required
Parts at a glance
Part B
AD8221BR
Analog Equipment GmbH.
- Lifecycle
- Active
- Stock
- 4387 PCS
- Package
- SOIC-8
- Series
- Amplificateurs linéaires - instruments, amplificateurs opérationnels, amplificateurs tampons
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | AD8226ARZ-R7 | AD8221BR | Why it matters |
|---|---|---|---|
| Number of Amplifiers | 1 | 1 | Both are single-channel instrumentation amplifiers, so channel count is functionally equivalent. |
| Input Offset Voltage (max) | 150 µV | 25 µV | Lower offset voltage improves DC accuracy; the AD8221BR is significantly more precise for high-gain precision measurements. |
| Input Offset Voltage Drift (max) | 2 µV/°C | 0.3 µV/°C | Lower drift maintains accuracy over temperature; the AD8221BR is far more stable across temperature extremes. |
| Gain Range | 1 to 1000 | 1 to 1000 | Both support the same programmable gain range via a single resistor, enabling equivalent gain configurations. |
| Gain Error (max, G=1000) | 0.1% | 0.02% | Lower gain error yields better signal fidelity at high gains; the AD8221BR offers superior gain accuracy. |
| Input Bias Current (max) | 27 nA | 1.5 nA | Lower bias current reduces errors with high source impedances; the AD8221BR is better suited for high-impedance sensors. |
| Common-Mode Rejection Ratio (min, G=1000) | 100 dB | 120 dB | Higher CMRR rejects common-mode noise more effectively; the AD8221BR provides superior noise immunity in noisy environments. |
| Input Voltage Noise (1 kHz) | 22 nV/√Hz | 8 nV/√Hz | Lower voltage noise improves SNR for small signals; the AD8221BR is preferable for low-noise precision applications. |
| Supply Voltage Range | ±2.25 V to ±18 V (4.5 V to 36 V) | ±2.3 V to ±18 V (4.6 V to 36 V) | Nearly identical supply ranges allow similar power-supply design; minor differences are negligible for most applications. |
| Operating Temperature Range | -40 °C to +125 °C | -40 °C to +85 °C | The AD8226ARZ-R7 supports a wider temperature range, making it suitable for higher-temperature environments where the AD8221BR may not be rated. |
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 | AD8226ARZ-R7 | AD8221BR |
|---|---|---|
| Supplier | - | Analog Devices Inc.,Rochester Electronics, LLC |
| Part Status | Active | Obsolete |
| Amplifier Type | Instrumentation | Instrumentation |
| Number of Circuits | 1 | 1 |
| Slew Rate | 0.6V/µs | 2V/µs |
| -3 dB Bandwidth | 1.5 MHz | 825 kHz |
| Current - Input Bias | 20 nA | 200 pA |
| Voltage - Input Offset | 100 µV | 25 µV |
| Supply Current | 350µA | 900µA |
| Current - Output / Channel | 13 mA | 18 mA |
| Voltage - Supply Span(Min) | 2.2 V | 4.6 V |
| Voltage - Supply Span(Max) | 36 V | 36 V |
| Operating Temperature | -40°C ~ 125°C | -40°C ~ 85°C |
| Mounting Type | Surface Mount | Surface Mount |
| Output Type | Rail-to-Rail | - |
Frequently asked questions
What are the primary functional differences between the AD8226ARZ-R7 and the AD8221BR?
The AD8226ARZ-R7 is an instrumentation amplifier with a rail-to-rail output and a wide supply range of ±2.25 V to ±18 V (or 4.5 V to 36 V single-supply), featuring a gain set by a single external resistor over a range of 1 to 1000. The AD8221BR is a high-performance instrumentation amplifier with superior DC precision (lower offset voltage, offset drift, and gain error) and higher CMRR, but its output is not rail-to-rail and it is optimized for ±2.3 V to ±18 V dual-supply operation. The AD8221BR is generally selected where highest accuracy and common-mode rejection are critical, while the AD8226ARZ-R7 is chosen for rail-to-rail output swing and single-supply flexibility.
Are the AD8226ARZ-R7 and AD8221BR pin-compatible and package-compatible?
Both devices are offered in an 8-lead SOIC package (the AD8226ARZ-R7 is specified as an 8-lead SOIC, and the AD8221BR is available in an 8-lead SOIC). However, pin compatibility must be verified against the specific datasheet pinout for each grade, because the gain-setting resistor connections and reference pin arrangements must match the target PCB layout. Designers should confirm the exact pin functions from the respective manufacturer datasheets before considering a drop-in replacement.
Which device offers better DC accuracy for precision sensor signal conditioning?
The AD8221BR provides superior DC precision, with lower input offset voltage, lower offset voltage drift, and tighter gain error specifications than the AD8226ARZ-R7. For applications such as precision bridge transducer amplification or low-level sensor conditioning where offset and drift dominate the error budget, the AD8221BR is the more accurate choice. The AD8226ARZ-R7 remains suitable for general-purpose instrumentation where rail-to-rail output and single-supply operation are more important than ultimate DC precision.
Can the AD8226ARZ-R7 operate from a single supply while the AD8221BR cannot?
The AD8226ARZ-R7 is specified for single-supply operation from 4.5 V to 36 V as well as dual supplies of ±2.25 V to ±18 V, and its rail-to-rail output allows it to swing close to the supply rails. The AD8221BR is specified for dual-supply operation of ±2.3 V to ±18 V and does not feature a rail-to-rail output. Therefore, for single-supply systems requiring output swing near ground, the AD8226ARZ-R7 is the appropriate selection, while the AD8221BR is intended for bipolar-supply precision applications.
How does common-mode rejection ratio (CMRR) compare between the two parts?
The AD8221BR is specified with higher CMRR than the AD8226ARZ-R7, making it preferable in environments with large common-mode voltages, such as industrial current-loop receivers or bridge sensors with high common-mode offsets. The AD8226ARZ-R7 still provides good CMRR for general-purpose instrumentation but does not match the AD8221BR's precision-grade rejection performance. Designers should consult the respective datasheet CMRR vs. frequency curves for the exact operating conditions of their application.
What gain-setting method do these instrumentation amplifiers use?
Both the AD8226ARZ-R7 and the AD8221BR use a single external resistor to set the gain, following the standard three-op-amp instrumentation amplifier topology. The gain equation and recommended resistor values are provided in each manufacturer datasheet. Because the internal resistor ratios and gain error specifications differ between the two devices, the same external resistor value will not necessarily produce identical gain accuracy, so the gain resistor should be recalculated for the selected part.
Which part is better suited for battery-powered portable instrumentation?
The AD8226ARZ-R7 is generally better suited for battery-powered portable designs because it supports single-supply operation down to 4.5 V and has a rail-to-rail output, allowing direct interface to low-voltage ADCs without additional level shifting. The AD8221BR requires a bipolar supply (minimum ±2.3 V) and its output does not swing rail-to-rail, which complicates low-voltage single-supply designs. Supply current and bandwidth specifications should be checked in the datasheets for the specific operating point.
Are these devices interchangeable in an existing precision measurement design?
They should not be treated as direct drop-in replacements without validation. The AD8221BR offers higher DC accuracy and CMRR but lacks rail-to-rail output and single-supply capability, while the AD8226ARZ-R7 offers rail-to-rail output and wider supply flexibility with lower precision-grade specifications. A substitution requires re-verification of gain error, offset drift, output swing headroom, supply configuration, and PCB pinout against the manufacturer datasheets for the target design.