Part A
AD8221ARMZ
テキサス・インスツルメンツ
- Lifecycle
- Active
- Stock
- 2550 個数
- Package
- MSOP-8
- Series
- リニアアンプ - 計装用、オペアンプ、バッファアンプ
Replacement verdict
Compatible functional replacement candidate
The AD8226ARMZ and AD8221ARMZ are both instrumentation amplifiers in the same 8-lead MSOP package with identical pinout, making them a viable functional replacement candidate. However, the AD8226ARMZ offers a wider supply range and rail-to-rail output, while the AD8221ARMZ provides higher gain accuracy and lower gain drift. Designers should validate gain-setting resistor requirements and bandwidth expectations before substituting.
Package Type
High match
Pin Configuration
High match
Supply Voltage Range
Validation required
Gain Bandwidth
Validation required
Parts at a glance
Part B
AD8226ARMZ
テキサス・インスツルメンツ
- Lifecycle
- Active
- Stock
- 5044 個数
- Package
- MSOP-8
- Series
- リニアアンプ - 計装用、オペアンプ、バッファアンプ
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | AD8226ARMZ | AD8221ARMZ | Why it matters |
|---|---|---|---|
| Number of Amplifiers | 1 | 1 | Both are single instrumentation amplifiers, so channel count is equivalent for substitution. |
| Input Offset Voltage (max) | 200 µV | 25 µV | Lower offset voltage improves DC accuracy; AD8221 offers significantly better precision. |
| Input Bias Current (max) | 27 nA | 1.5 nA | Lower bias current reduces errors in high-impedance sensor interfaces; AD8221 is superior here. |
| Gain Bandwidth Product | 1.5 MHz | 825 kHz | Higher bandwidth supports faster signal processing; AD8226 provides wider frequency response. |
| CMRR (min, G=100) | 80 dB | 100 dB | Higher common-mode rejection improves noise immunity in differential measurement; AD8221 is better. |
| Input Voltage Noise (1 kHz) | 22 nV/√Hz | 8 nV/√Hz | Lower voltage noise benefits low-level signal amplification; AD8221 has notably lower noise. |
| Supply Voltage Range | ±1.35 V to ±18 V | ±2.3 V to ±18 V | Wider low-voltage operation allows AD8226 to run on lower supplies, affecting compatibility in low-voltage systems. |
| Quiescent Supply Current (max) | 1.0 mA | 1.0 mA | Similar power consumption means neither part has a clear advantage for power-sensitive designs. |
| Operating Temperature Range | -40 °C to +125 °C | -40 °C to +85 °C | AD8226 supports higher ambient temperatures, which matters for industrial and automotive environments. |
| Package | 8-Lead MSOP | 8-Lead MSOP | Identical package and pinout enable drop-in substitution 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 | AD8221ARMZ | AD8226ARMZ |
|---|---|---|
| Part Status | Active | Active |
| Amplifier Type | Instrumentation | Instrumentation |
| Number of Circuits | 1 | 1 |
| Slew Rate | 2V/µs | 0.6V/µs |
| -3 dB Bandwidth | 825 kHz | 1.5 MHz |
| Current - Input Bias | 500 pA | 20 nA |
| Voltage - Input Offset | 60 µV | 100 µV |
| Supply Current | 900µA | 350µA |
| Current - Output / Channel | 18 mA | 13 mA |
| Voltage - Supply Span(Min) | 4.6 V | 2.2 V |
| Voltage - Supply Span(Max) | 36 V | 36 V |
| Operating Temperature | -40°C ~ 85°C | -40°C ~ 125°C |
| Mounting Type | Surface Mount | Surface Mount |
| Output Type | - | Rail-to-Rail |
Frequently asked questions
What are the key differences between the AD8226ARMZ and AD8221ARMZ instrumentation amplifiers?
The AD8226ARMZ is a wide-supply-range, rail-to-rail output in-amp with a gain range of 1 to 1000, specified over a supply range of ±2.25 V to ±18 V (4.5 V to 36 V), and is characterized for operation up to 125°C. The AD8221ARMZ is a high-performance in-amp with superior CMRR (typically 90 dB at G=1, up to 130 dB at G=1000), lower offset voltage (25 µV max at G=1), and lower noise (8 nV/√Hz at 1 kHz), specified over a supply range of ±2.3 V to ±18 V. The AD8221ARMZ is optimized for precision, low-noise applications, while the AD8226ARMZ targets wider supply and temperature range with rail-to-rail output swing.
Are the AD8226ARMZ and AD8221ARMZ pin-compatible in the same MSOP-8 package?
Both devices are offered in an 8-lead MSOP (RMZ suffix) package and share the standard instrumentation amplifier pinout: pin 1 = -IN, pin 2 = RG, pin 3 = RG, pin 4 = -VS, pin 5 = REF, pin 6 = VOUT, pin 7 = +VS, pin 8 = +IN. This common pinout allows board-level interchangeability, but electrical differences must be validated before substitution.
How do the gain-setting resistor requirements compare between the AD8226ARMZ and AD8221ARMZ?
Both devices use a single external resistor RG to set gain. For the AD8226ARMZ, gain is set by G = 1 + 49.4 kΩ/RG. For the AD8221ARMZ, gain is set by G = 1 + 49.4 kΩ/RG. The gain equations are identical, so the same RG value produces the same nominal gain in both parts, though gain error and nonlinearity specifications differ between the two devices.
Which device offers better common-mode rejection ratio (CMRR)?
The AD8221ARMZ provides higher CMRR. At G=1, the AD8221ARMZ specifies CMRR of 80 dB minimum (90 dB typical), while the AD8226ARMZ specifies 80 dB minimum (86 dB typical) at G=1. At higher gains the AD8221ARMZ reaches up to 130 dB typical at G=1000, reflecting its precision-grade architecture.
How do the input offset voltage specifications differ between the AD8226ARMZ and AD8221ARMZ?
The AD8221ARMZ has a lower maximum input offset voltage of 25 µV at G=1 (60 µV max at G=1000), with typical drift of 0.3 µV/°C. The AD8226ARMZ specifies a maximum input offset voltage of 200 µV at G=1, with typical drift of 2 µV/°C. For precision DC applications, the AD8221ARMZ is the lower-offset option.
What are the supply voltage and temperature range differences between the two parts?
The AD8226ARMZ operates on a supply range of ±2.25 V to ±18 V (4.5 V to 36 V single supply) and is specified over the −40°C to +125°C temperature range. The AD8221ARMZ operates on ±2.3 V to ±18 V (4.6 V to 36 V single supply) and is specified over the −40°C to +85°C temperature range. The AD8226ARMZ therefore offers a slightly wider supply headroom and an extended temperature rating.
How does output swing differ between the AD8226ARMZ and AD8221ARMZ?
The AD8226ARMZ features rail-to-rail output swing, allowing the output to approach both supply rails, which is advantageous in low-voltage single-supply designs. The AD8221ARMZ has a more limited output swing that does not extend fully to the rails. Designs requiring maximum dynamic range near the supply rails should account for this difference.
Which device has lower input voltage noise?
The AD8221ARMZ has lower input voltage noise, specified at 8 nV/√Hz at 1 kHz (G=1). The AD8226ARMZ specifies 22 nV/√Hz at 1 kHz. For low-level signal amplification where noise performance is critical, the AD8221ARMZ is the preferred choice.
Can the AD8226ARMZ and AD8221ARMZ be used interchangeably in an existing design?
Because both share the same MSOP-8 pinout and identical gain equation, they are pin-compatible, but they are not electrically identical. Differences in offset voltage, CMRR, noise, output swing, and specified temperature range mean a substitution must be validated against the application's accuracy, noise, supply, and thermal requirements using the respective manufacturer datasheets before interchange.