Part A
AD8221ARM
Công ty Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 2853 PCS
- Package
- TSSOP-8
- Series
- Linear - Amplifiers - Instrumentation, OP Amps, Buffer Amps
Replacement verdict
Compatible functional replacement candidate
The AD8221ARM and AD822ARM-REEL share the same instrumentation amplifier function, SOIC-8 package, and dual-supply architecture, making the AD8221ARM a viable functional replacement candidate for the AD822ARM-REEL in most designs. However, the AD8221ARM offers substantially higher gain bandwidth and a wider specified supply range, so gain-setting resistor values and AC performance should be re-validated against the target circuit before substitution.
Amplifier Function
High match
Package Type
High match
Gain Bandwidth Product
Validation required
Supply Voltage Range
Validation required
Parts at a glance
Part B
AD822ARM-REEL
Công ty Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 2632 PCS
- Package
- TSSOP-8
- Series
- Linear - Amplifiers - Instrumentation, 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 | AD8221ARM | AD822ARM-REEL | Why it matters |
|---|---|---|---|
| Amplifier Type | Instrumentation Amplifier | General Purpose Operational Amplifier (Dual) | These are fundamentally different amplifier classes; an instrumentation amp is optimized for differential signal acquisition, while a dual op-amp is a general-purpose building block, so they are not functionally interchangeable. |
| Number of Channels | 1 | 2 | Channel count determines how many independent signal paths can be processed per package, affecting board layout and circuit architecture. |
| Input Offset Voltage (max) | 60 µV | 800 µV | Lower offset voltage yields better DC accuracy; the instrumentation amp offers significantly tighter offset, which matters for precision measurement. |
| Gain Configuration | Set by single external resistor (G = 1 to 1000) | Fixed internal gain (unity-gain stable op-amp) | The instrumentation amp allows programmable gain via one resistor, while the op-amp requires external feedback networks, changing design complexity and flexibility. |
| Input Bias Current (typ) | 0.5 nA | 2 pA | Bias current affects error in high-impedance sources; the op-amp's JFET input offers much lower bias current, relevant for high-impedance sensing. |
| Gain Bandwidth Product | 825 kHz (at G = 1) | 1.8 MHz | Bandwidth limits the frequency range of signals that can be accurately amplified; the op-amp provides wider small-signal bandwidth. |
| Supply Voltage Range | ±2.3 V to ±18 V (dual supply) | ±4.5 V to ±18 V (dual supply) | The usable supply range determines compatibility with low-voltage systems; the instrumentation amp operates at lower minimum supplies. |
| Package | 8-Lead MSOP | 8-Lead MSOP | Package footprint affects PCB layout and assembly; identical packages ease drop-in substitution mechanically, though electrical differences remain. |
| Operating Temperature Range | −40 °C to +85 °C | −40 °C to +85 °C | Temperature range confirms suitability for industrial environments; both parts share the same rated range. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | AD8221ARM | AD822ARM-REEL |
|---|---|---|
| Supplier | - | Analog Devices Inc.,Rochester Electronics, LLC |
| Part Status | Obsolete | Obsolete |
| Amplifier Type | Instrumentation | General Purpose |
| Number of Circuits | 1 | 2 |
| Output Type | - | Rail-to-Rail |
| Slew Rate | 2V/µs | 3V/µs |
| Gain Bandwidth Product | - | 1.9 MHz |
| -3 dB Bandwidth | 825 kHz | 1.9 MHz |
| Current - Input Bias | 500 pA | 2 pA |
| Voltage - Input Offset | 60 µV | 400 µV |
| Supply Current | 900µA | 1.24mA |
| Current - Output / Channel | 18 mA | 20 mA |
| Voltage - Supply Span(Min) | 4.6 V | 5 V |
| Voltage - Supply Span(Max) | 36 V | 30 V |
| Operating Temperature | -40°C ~ 85°C | -40°C ~ 85°C |
| Mounting Type | Surface Mount | Surface Mount |
Frequently asked questions
What are the key differences between the AD8221ARM and the AD822ARM-REEL?
The AD8221ARM is a precision instrumentation amplifier from Analog Devices supplied in an 8-lead MSOP (RM) package, while the AD822ARM-REEL refers to the AD822 (dual, single-supply op amp) in an 8-lead MSOP package supplied on a reel for automated assembly. They are fundamentally different device families: the AD8221 is a single instrumentation amplifier, whereas the AD822 is a dual operational amplifier. They are not interchangeable.
Are the AD8221ARM and AD822ARM-REEL pin-compatible?
No. Although both are offered in an 8-lead MSOP package, their pin functions differ because they are different device types. The AD8221 instrumentation amplifier uses its 8 pins for gain-setting and input/output functions, while the AD822 dual op amp uses a standard dual-op-amp pinout. Pin assignments must be verified against each device's respective datasheet before any layout consideration.
What is the functional role of the AD8221ARM?
The AD8221ARM is a high-performance instrumentation amplifier designed for precision signal conditioning, offering high common-mode rejection and a gain set by a single external resistor. It is typically used for transducer interfacing, bridge amplification, and precision data acquisition.
What is the functional role of the AD822ARM-REEL?
The AD822ARM-REEL is a dual, single-supply operational amplifier supplied in reel packaging for high-volume automated placement. It is used for general-purpose signal conditioning, buffering, and amplification where a dual op amp in a small package is required.
Can the AD822ARM-REEL be used as a direct replacement for the AD8221ARM?
No. The AD8221ARM is a single instrumentation amplifier, while the AD822ARM-REEL is a dual operational amplifier. Their functions, internal topology, and pinouts differ, so a direct substitution is not valid. Any replacement requires full validation against the manufacturer datasheets and the target circuit requirements.
Why does the "REEL" suffix matter for the AD822ARM-REEL?
The "REEL" suffix indicates the device is supplied in tape-and-reel packaging intended for automated pick-and-place assembly lines. It does not change the electrical characteristics of the AD822 device itself; it only defines the shipping and handling format for high-volume production.
Do both parts share the same package outline?
Both the AD8221ARM and the AD822ARM-REEL are offered in an 8-lead MSOP package, so the package outline and land pattern family are similar. However, identical package outline does not imply identical pin functions or electrical behavior, and each device's datasheet must be consulted for exact pin assignments and dimensions.