Part A
AD8422BRZ
아날로그 디바이스(주)
- Lifecycle
- Active
- Stock
- 3871 PCS
- Package
- SOIC-8
- Series
- 선형 증폭기 - 계측기, 연산 증폭기, 완충 증폭기
Replacement verdict
Compatible functional replacement candidate
The AD8422BRZ and AD8421ARZ-RL are both precision instrumentation amplifiers from Analog Devices sharing a functionally equivalent pinout and gain architecture, making the AD8422BRZ a viable functional replacement candidate for the AD8421ARZ-RL in many designs. However, the two parts differ in supply voltage range, bandwidth, and noise performance, so the substitution should be validated against the specific application's signal chain requirements before adoption.
Supply Voltage Range
Validation required
Bandwidth
Validation required
Input Voltage Noise
Validation required
Package Type
High match
Parts at a glance
Part B
AD8421ARZ-RL
아날로그 디바이스(주)
- Lifecycle
- Active
- Stock
- 4538 PCS
- Package
- SOIC-8
- Series
- 선형 증폭기 - 계측기, 연산 증폭기, 완충 증폭기
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | AD8422BRZ | AD8421ARZ-RL | Why it matters |
|---|---|---|---|
| Gain Bandwidth Product (GBP) | 2.2 MHz | 10 MHz | Higher bandwidth allows the amplifier to handle faster signals and wider frequency content, which is critical for high-speed signal conditioning applications. |
| Input Voltage Noise (1 kHz) | 8 nV/√Hz | 3 nV/√Hz | Lower input voltage noise improves the signal-to-noise ratio, which is essential when amplifying small signals in precision measurement systems. |
| Input Offset Voltage (max) | 70 µV | 60 µV | Lower offset voltage reduces DC error at the output, improving accuracy in precision instrumentation and sensor interface circuits. |
| Supply Current per Amplifier | 300 µA | 2.3 mA | Lower supply current is important for battery-powered and low-power portable designs where power budget is a key constraint. |
| CMRR (DC to 60 Hz, G=1000) | 120 dB | 134 dB | Higher common-mode rejection ratio suppresses unwanted common-mode signals, which is critical for extracting small differential signals in noisy environments. |
| Gain Range | 1 to 1000 | 1 to 10000 | A wider gain range provides greater flexibility for amplifying very small signals, which matters in high-gain sensor applications. |
| Input Bias Current (max) | 1 nA | 2 nA | Lower input bias current reduces errors in high-impedance source applications, improving measurement accuracy. |
| Operating Temperature Range | -40°C to +85°C | -40°C to +125°C | A wider operating temperature range enables use in harsh industrial and automotive environments with higher ambient temperatures. |
| Package | 8-Lead SOIC | 8-Lead SOIC | Package compatibility affects PCB footprint and assembly; identical packages allow drop-in replacement 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 | AD8422BRZ | AD8421ARZ-RL |
|---|---|---|
| Supplier | - | Analog Devices Inc. |
| Part Status | Active | Active |
| Amplifier Type | Instrumentation | Instrumentation |
| Number of Circuits | 1 | 1 |
| Slew Rate | 0.8V/µs | 35V/µs |
| -3 dB Bandwidth | 2.2 MHz | 10 MHz |
| Current - Input Bias | 200 pA | 1 nA |
| Voltage - Input Offset | 25 µV | 60 µV |
| Supply Current | 300µA | 2mA |
| Current - Output / Channel | 20 mA | 65 mA |
| Voltage - Supply Span(Min) | 4.6 V | 5 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 |
| Output Type | Rail-to-Rail | - |
Frequently asked questions
What are the key differences between the AD8422BRZ and AD8421ARZ-RL?
The AD8422BRZ is a high-precision, low-power instrumentation amplifier with a typical input offset voltage of 25 µV and a gain bandwidth product of 2.2 MHz, supplied in an 8-lead SOIC package. The AD8421ARZ-RL is a lower-noise instrumentation amplifier with a typical input voltage noise of 3 nV/√Hz and a gain bandwidth product of 10 MHz, also in an 8-lead SOIC package but supplied in tape-and-reel form. The AD8422BRZ is optimized for low power and DC precision, while the AD8421ARZ-RL is optimized for low noise and higher bandwidth.
Can the AD8422BRZ and AD8421ARZ-RL be used interchangeably in the same PCB footprint?
Both devices are offered in an 8-lead SOIC package, so the physical footprint and pinout are compatible. However, electrical differences such as supply current, noise, bandwidth, and gain-setting resistor requirements mean they are not electrically interchangeable without verifying the circuit design against the respective datasheets.
How do the supply current requirements of the AD8422BRZ and AD8421ARZ-RL compare?
The AD8422BRZ typically draws about 300 µA of supply current, making it suitable for low-power applications. The AD8421ARZ-RL typically draws about 2.3 mA. Designs powered from limited current budgets should account for this difference.
Which device offers lower input voltage noise, the AD8422BRZ or the AD8421ARZ-RL?
The AD8421ARZ-RL offers lower input voltage noise, with a typical value of 3 nV/√Hz at 1 kHz. The AD8422BRZ has a typical input voltage noise of 8 nV/√Hz at 1 kHz. For low-noise signal acquisition, the AD8421ARZ-RL is the better choice.
What is the gain bandwidth product of each device?
The AD8422BRZ has a gain bandwidth product of 2.2 MHz, while the AD8421ARZ-RL has a gain bandwidth product of 10 MHz. The AD8421ARZ-RL supports higher bandwidth at a given gain.
Do both devices use an external gain-setting resistor?
Yes. Both the AD8422BRZ and AD8421ARZ-RL use a single external resistor to set the gain, following the standard instrumentation amplifier gain equation G = 1 + (49.4 kΩ / RG). The resistor value must be selected according to the desired gain for each device.
What are the input offset voltage specifications for the AD8422BRZ and AD8421ARZ-RL?
The AD8422BRZ has a typical input offset voltage of 25 µV with a maximum of 70 µV over the specified temperature range. The AD8421ARZ-RL has a typical input offset voltage of 60 µV with a maximum of 150 µV. The AD8422BRZ provides better DC precision.
Are both devices specified for the same supply voltage range?
Both the AD8422BRZ and AD8421ARZ-RL operate from dual supplies of ±2.3 V to ±18 V (or single supplies of 4.6 V to 36 V). Designers should confirm the exact limits and derating requirements in the respective manufacturer datasheets for the target operating conditions.