Part A
AD8021ARMZ
Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 2172 PCS
- Package
- MSOP-8
- Series
- Linear - Amplifiers - Instrumentation, OP Amps, Buffer Amps
Replacement verdict
Not a drop-in replacement
The AD8021ARMZ and AD8022ARM are not drop-in replacements for one another. Although both are high-speed voltage-feedback operational amplifiers in 8-lead MSOP packages, they differ in channel count, supply voltage range, quiescent current, and input bias current, so the AD8022ARM cannot be substituted directly for the AD8021ARMZ without circuit redesign and validation.
Different channel count
Different supply voltage range
Different quiescent current
Different input bias current
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | AD8021ARMZ | AD8022ARM | Why it matters |
|---|---|---|---|
| Number of Amplifiers | 1 | 2 | Channel count determines whether a single dual device can replace two singles, affecting board space and cost. |
| Gain Bandwidth Product | 490 MHz | 100 MHz | GBW sets the maximum signal frequency the amplifier can handle at a given gain, directly limiting high-speed applications. |
| -3 dB Bandwidth (G=1) | 200 MHz | 110 MHz | Closed-loop bandwidth indicates usable frequency range in unity-gain configurations for buffering and driving. |
| Slew Rate | 460 V/µs | 50 V/µs | Slew rate limits how fast large-signal outputs can change, critical for pulse and high-frequency large-signal fidelity. |
| Input Voltage Noise Density | 2.1 nV/√Hz | 4.5 nV/√Hz | Lower input noise improves signal-to-noise ratio in low-level signal amplification and precision front ends. |
| Supply Voltage Range | ±2.25 V to ±12 V | ±2.5 V to ±12 V | Supply range determines compatibility with the system power rails and headroom available for signal swing. |
| Quiescent Supply Current per Amplifier | 7.7 mA | 4 mA | Quiescent current affects power budget and thermal load, important in dense or power-sensitive designs. |
| Input Offset Voltage (max) | 1 mV | 1.5 mV | Offset voltage contributes DC error; tighter offset improves accuracy in precision and DC-coupled stages. |
| Package | 8-Lead MSOP | 8-Lead MSOP | Package footprint and pinout must match for drop-in board compatibility and thermal layout. |
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 | AD8021ARMZ | AD8022ARM |
|---|---|---|
| Supplier | - | Rochester Electronics, LLC |
| Part Status | Active | Obsolete |
| Amplifier Type | Voltage Feedback | Voltage Feedback |
| Number of Circuits | 1 | 2 |
| Slew Rate | 460V/µs | 50V/µs |
| Gain Bandwidth Product | - | 100 MHz |
| -3 dB Bandwidth | 560 MHz | 130 MHz |
| Current - Input Bias | 7.5 µA | 2.5 µA |
| Voltage - Input Offset | 400 µV | 1.5 mV |
| Supply Current | 7.8mA | 4mA |
| Current - Output / Channel | 70 mA | 55 mA |
| Voltage - Supply Span(Min) | 4.5 V | 4.5 V |
| Voltage - Supply Span(Max) | 24 V | 26 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 AD8021ARMZ and the AD8022ARM?
The AD8021ARMZ is a single, high-speed, low-noise operational amplifier, while the AD8022ARM is a dual, high-speed operational amplifier. The AD8021ARMZ is specified for a 3 dB bandwidth of 490 MHz (G = +1) and a slew rate of 460 V/µs, whereas the AD8022ARM is specified for a 3 dB bandwidth of 130 MHz (G = +1) and a slew rate of 100 V/µs. The AD8021ARMZ is optimized for lower voltage noise (2.1 nV/√Hz typical) compared to the AD8022ARM (4.5 nV/√Hz typical).
Are the AD8021ARMZ and AD8022ARM pin-compatible?
No. The AD8021ARMZ is a single op amp in an 8-lead MSOP package, while the AD8022ARM is a dual op amp in an 8-lead MSOP package. Although both use the same package footprint, the pin functions differ: the AD8021ARMZ uses pins for offset null and disable, whereas the AD8022ARM uses those pins for the second amplifier's inputs and output. They are not direct drop-in replacements.
Can the AD8022ARM be used as a replacement for two AD8021ARMZ amplifiers?
Not directly. While the AD8022ARM integrates two amplifiers in one package, its AC and DC specifications differ significantly from the AD8021ARMZ. The AD8021ARMZ offers higher bandwidth (490 MHz vs. 130 MHz), faster slew rate (460 V/µs vs. 100 V/µs), and lower input voltage noise (2.1 nV/√Hz vs. 4.5 nV/√Hz). Circuit performance must be revalidated if substituting the AD8022ARM for two AD8021ARMZ devices.
What are the supply voltage ranges for the AD8021ARMZ and AD8022ARM?
Both devices operate from dual supplies. The AD8021ARMZ is specified for a supply voltage range of ±2.5 V to ±12 V (5 V to 24 V total). The AD8022ARM is specified for a supply voltage range of ±2.5 V to ±6 V (5 V to 12 V total). The AD8021ARMZ therefore supports a wider maximum supply voltage.
Which device is better suited for low-noise applications?
The AD8021ARMZ is better suited for low-noise applications. Its input voltage noise density is 2.1 nV/√Hz typical at 1 kHz, compared to 4.5 nV/√Hz typical for the AD8022ARM. The AD8021ARMZ also specifies a lower input current noise density of 2.1 pA/√Hz typical versus 2.5 pA/√Hz typical for the AD8022ARM.
Do both amplifiers support disable or power-down functionality?
No. The AD8021ARMZ includes a disable pin (Pin 8) that allows the amplifier to be powered down, reducing quiescent current. The AD8022ARM does not provide a disable or power-down function; all eight pins are dedicated to the two amplifiers and their supplies.
What are the typical quiescent supply currents for the AD8021ARMZ and AD8022ARM?
The AD8021ARMZ has a typical quiescent supply current of 7.7 mA per amplifier. The AD8022ARM has a typical quiescent supply current of 4.0 mA per amplifier (8.0 mA total for the dual). The AD8021ARMZ consumes more current per amplifier but delivers higher bandwidth and lower noise.
Are the AD8021ARMZ and AD8022ARM specified for the same operating temperature range?
Yes. Both the AD8021ARMZ and the AD8022ARM are specified for the industrial temperature range of −40°C to +85°C. Both are offered in 8-lead MSOP packages and are RoHS-compliant.