Part A
AD8420ARMZ
Công ty Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 1829 PCS
- Package
- MSOP-8
- Series
- Linear - Amplifiers - Instrumentation, OP Amps, Buffer Amps
Replacement verdict
Compatible functional replacement candidate
The AD8420ARMZ can serve as a functional replacement candidate for the AD8422BRMZ in many low-power instrumentation amplifier applications, but it is not a drop-in equivalent. Designers must validate gain-setting resistor values, bandwidth, and noise performance against the specific circuit requirements before substituting, since the two devices differ in supply current, bandwidth, and voltage noise characteristics.
Package Type
High match
Supply Current
Validation required
Bandwidth
Validation required
Voltage Noise
Validation required
Parts at a glance
Part B
AD8422BRMZ
Công ty Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 2679 PCS
- Package
- MSOP-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 | AD8422BRMZ | AD8420ARMZ | Why it matters |
|---|---|---|---|
| Number of Amplifiers | 1 | 1 | Both are single instrumentation amplifiers, so channel count is equivalent for substitution. |
| Supply Voltage Range | 4.5 V to 36 V (single), ±2.25 V to ±18 V (dual) | 2.7 V to 36 V (single), ±1.35 V to ±18 V (dual) | The AD8420 supports lower supply voltages, enabling operation in low-voltage systems where the AD8422 cannot run. |
| Gain Bandwidth Product | 2.2 MHz | 0.25 MHz | The AD8422 offers much wider bandwidth, which is critical for higher-frequency signal conditioning. |
| Input Offset Voltage (max) | 70 µV | 250 µV | Lower offset voltage improves DC accuracy; the AD8422 is preferable for precision measurement. |
| Input Voltage Noise Density | 8 nV/√Hz | 30 nV/√Hz | Lower noise density benefits low-level signal amplification; the AD8422 is significantly quieter. |
| CMRR (G=100) | 114 dB | 100 dB | Higher common-mode rejection improves performance in noisy environments with large common-mode signals. |
| Quiescent Supply Current | 300 µA | 85 µA | The AD8420 draws much less current, making it better suited for battery-powered and low-power designs. |
| Operating Temperature Range | -40 °C to +85 °C | -40 °C to +85 °C | Identical temperature ratings mean both are suitable for the same industrial environments. |
| Package | 8-Lead MSOP | 8-Lead MSOP | Same package and pinout simplify board-level substitution without layout changes. |
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 | AD8420ARMZ | AD8422BRMZ |
|---|---|---|
| Part Status | Active | Active |
| Amplifier Type | Instrumentation | Instrumentation |
| Number of Circuits | 1 | 1 |
| Output Type | Rail-to-Rail | Rail-to-Rail |
| Slew Rate | 1V/µs | 0.8V/µs |
| -3 dB Bandwidth | 250 kHz | 2.2 MHz |
| Current - Input Bias | 20 nA | 200 pA |
| Voltage - Input Offset | 250 µV | 50 µV |
| Supply Current | 85µA | 300µA |
| Current - Output / Channel | 10 mA | 20 mA |
| Voltage - Supply Span(Min) | 2.7 V | 4.6 V |
| Voltage - Supply Span(Max) | 36 V | 36 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 AD8422BRMZ and AD8420ARMZ instrumentation amplifiers?
The AD8422BRMZ is a high-precision, low-power instrumentation amplifier with a typical input offset voltage of 25 µV, a gain bandwidth product of 2.2 MHz, and a supply range of ±2.3 V to ±18 V. The AD8420ARMZ is a micropower instrumentation amplifier with a typical input offset voltage of 125 µV, a bandwidth of 200 kHz at G = 100, and a supply range of 2.7 V to 36 V. The AD8422BRMZ targets higher precision and wider bandwidth applications, while the AD8420ARMZ targets ultra-low power consumption.
Are the AD8422BRMZ and AD8420ARMZ pin-compatible?
Both devices are offered in 8-lead MSOP (RM) packages, but pin compatibility must be verified against the respective manufacturer datasheets. The AD8422BRMZ and AD8420ARMZ share the same package outline, but the internal pin functions and external component requirements may differ. Designers should confirm pin assignments and recommended external circuitry from the official Analog Devices datasheets before considering a direct replacement.
Which device offers lower power consumption, the AD8422BRMZ or the AD8420ARMZ?
The AD8420ARMZ is the lower-power option. It is specified as a micropower instrumentation amplifier with a typical supply current of 85 µA. The AD8422BRMZ has a typical supply current of 300 µA. For battery-powered or energy-harvesting applications where quiescent current is critical, the AD8420ARMZ is the more suitable choice.
How do the input offset voltage specifications compare between the AD8422BRMZ and AD8420ARMZ?
The AD8422BRMZ offers superior DC precision with a typical input offset voltage of 25 µV and a maximum of 75 µV. The AD8420ARMZ has a typical input offset voltage of 125 µV and a maximum of 250 µV. For applications requiring high DC accuracy, such as precision sensor interfaces, the AD8422BRMZ provides better offset performance.
What are the bandwidth differences between the AD8422BRMZ and AD8420ARMZ?
The AD8422BRMZ has a gain bandwidth product of 2.2 MHz, allowing wider signal bandwidth at a given gain. The AD8420ARMZ has a bandwidth of 200 kHz at a gain of 100. For high-frequency signal conditioning or fast-responding control loops, the AD8422BRMZ is the higher-bandwidth solution, while the AD8420ARMZ is adequate for low-frequency sensor applications.
Can the AD8422BRMZ and AD8420ARMZ operate from the same supply voltage range?
The AD8422BRMZ operates from a dual supply of ±2.3 V to ±18 V (or single supply of 4.6 V to 36 V). The AD8420ARMZ operates from a single supply of 2.7 V to 36 V. Both devices support a 36 V maximum total supply, but the AD8420ARMZ can operate at a lower minimum supply of 2.7 V, making it suitable for low-voltage systems. The AD8422BRMZ requires a minimum total supply of 4.6 V.
Which device is better suited for high-precision bridge sensor applications?
The AD8422BRMZ is generally better suited for high-precision bridge sensor applications due to its lower input offset voltage (25 µV typical), lower offset drift, and higher gain bandwidth product. The AD8420ARMZ, with its higher offset voltage (125 µV typical) and lower bandwidth, is more appropriate for low-power, lower-precision sensor interfaces where micropower operation is the primary requirement.