Part A
AD822AR
Công ty Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 6939 PCS
- Package
- SOIC-8
- Series
- Linear - Amplifiers - Instrumentation, OP Amps, Buffer Amps
Replacement verdict
Not a drop-in replacement
The AD822AR and AD8221AR-REEL7 are not drop-in replacements for each other. The AD822AR is a dual-channel general-purpose operational amplifier, while the AD8221AR-REEL7 is a single-channel precision instrumentation amplifier. They differ in channel count, amplifier architecture, package footprint, and gain configuration, so substituting one for the other requires a full circuit redesign rather than a direct swap.
Different amplifier type
Different channel count
Different footprint
Different gain configuration
Parts at a glance
Part B
AD8221AR-REEL7
Công ty Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 4108 PCS
- Package
- SOIC-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 | AD822AR | AD8221AR-REEL7 | Why it matters |
|---|---|---|---|
| Amplifier Type | General Purpose, Dual | Instrumentation | Determines the fundamental function; a dual op-amp and a single instrumentation amplifier are not directly interchangeable in a circuit. |
| Number of Channels | 2 | 1 | Channel count affects how many signal paths can be processed per package and the pinout compatibility. |
| Input Offset Voltage (Max) | 800 µV | 60 µV | Lower offset voltage yields higher DC accuracy, critical for precision measurement and instrumentation applications. |
| Gain Bandwidth Product | 1.9 MHz | 825 kHz | GBW sets the achievable closed-loop bandwidth and small-signal response for a given gain configuration. |
| Input Bias Current (Typ) | 2 pA | 0.5 nA | Bias current affects error in high-impedance source applications; lower bias current reduces offset errors. |
| Supply Voltage Range | ±2.5 V to ±15 V (5 V to 30 V) | ±2.3 V to ±18 V (4.6 V to 36 V) | Supply range determines compatibility with the system power rails and headroom available for signal swing. |
| Gain Setting | External resistors (op-amp configuration) | Single external resistor | The method of setting gain affects circuit complexity and the achievable gain accuracy and range. |
| Package / Pin Count | 8-Lead SOIC | 8-Lead SOIC | Same package footprint allows board-level drop-in placement, though internal pin functions differ between the two parts. |
| Operating Temperature Range | -40 °C to +85 °C | -40 °C to +85 °C | Confirms both parts are rated for the same industrial temperature environment. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | AD822AR | AD8221AR-REEL7 |
|---|---|---|
| Supplier | - | Analog Devices Inc.,Rochester Electronics, LLC |
| Part Status | Obsolete | Obsolete |
| Amplifier Type | General Purpose | Instrumentation |
| Number of Circuits | 2 | 1 |
| Slew Rate | 3V/µs | 2V/µs |
| -3 dB Bandwidth | 1.9 MHz | 825 kHz |
| Current - Input Bias | 2 pA | 500 pA |
| Voltage - Input Offset | 400 µV | 60 µV |
| Supply Current | 1.24mA | 900µA |
| Current - Output / Channel | 20 mA | 18 mA |
| Voltage - Supply Span(Min) | 5 V | 4.6 V |
| Voltage - Supply Span(Max) | 30 V | 36 V |
| Operating Temperature | -40°C ~ 85°C | -40°C ~ 85°C |
| Mounting Type | Surface Mount | Surface Mount |
| Output Type | Rail-to-Rail | - |
| Gain Bandwidth Product | 1.9 MHz | - |
Frequently asked questions
Are the AD822AR and AD8221AR-REEL7 interchangeable in an existing circuit?
No, they are not directly interchangeable. The AD822AR is a dual, general-purpose, low-power operational amplifier, while the AD8221AR-REEL7 is a single, high-performance instrumentation amplifier. They differ in function, pinout, package, and key specifications, so a direct drop-in substitution is not possible without circuit redesign.
What are the fundamental functional differences between the AD822AR and AD8221AR-REEL7?
The AD822AR is a dual operational amplifier (two op amps per package) intended for general signal conditioning. The AD8221AR-REEL7 is a monolithic instrumentation amplifier with a single channel, designed for precision differential signal amplification with a single external gain resistor.
How do the package and pinout of the AD822AR and AD8221AR-REEL7 compare?
The AD822AR is offered in an 8-lead SOIC package (among other options) with the standard dual-op-amp pinout. The AD8221AR-REEL7 is supplied in an 8-lead SOIC package with the standard instrumentation amplifier pinout (gain resistor pins, +IN, -IN, REF, OUTPUT, +VS, -VS). The pin functions are not compatible, so the two devices cannot share the same PCB footprint without layout changes.
What are the key gain-setting differences between the AD822AR and AD8221AR-REEL7?
The AD822AR, as a dual op amp, requires external feedback resistors to set gain in each amplifier stage. The AD8221AR-REEL7 is a fixed-topology instrumentation amplifier whose gain is set by a single external resistor (R_G) according to the manufacturer-specified gain equation, providing a defined and stable gain range without external op-amp feedback networks.
Which device is better suited for precision differential signal acquisition?
The AD8221AR-REEL7 is specifically designed for precision differential signal acquisition, offering high common-mode rejection ratio (CMRR), low offset voltage, and low drift as specified in its datasheet. The AD822AR is a general-purpose dual op amp and would require an external resistor network to build a comparable differential amplifier, with generally lower guaranteed CMRR performance.
Do the AD822AR and AD8221AR-REEL7 have the same supply voltage requirements?
Both devices are specified for operation on dual supplies (for example, ±5 V to ±15 V) per their respective datasheets, but the exact specified supply ranges, quiescent current, and output swing characteristics differ. Designers must consult each device's datasheet to confirm compatibility with the target supply rails.
Can the AD8221AR-REEL7 be used as a replacement for one channel of the AD822AR?
Not as a pin-compatible replacement. Although both are 8-lead SOIC devices, their pinouts and functions differ. Replacing one channel of the AD822AR with an AD8221AR-REEL7 would require PCB redesign, revalidation of gain, offset, and common-mode performance, and confirmation that the instrumentation amplifier topology suits the application.
What does the "-REEL7" suffix indicate on the AD8221AR-REEL7?
The "-REEL7" suffix denotes the manufacturer's packaging and shipping format: the AD8221AR devices are supplied on a 7-inch tape-and-reel for automated assembly. It does not indicate a different silicon die or electrical grade compared with the corresponding AD8221AR base part number.