Part A
AD8420ARMZ
Компания Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 1829 ПКС
- Package
- MSOP-8
- Series
- Линейные - Усилетели - Приборы, ОП Усилетели, Буферные Усилетели
Replacement verdict
Compatible functional replacement candidate
The AD8420ARMZ and AD8422ARMZ-RL are both precision instrumentation amplifiers in the same 8-lead MSOP package, but they differ in supply voltage range, quiescent current, and gain-bandwidth characteristics. The AD8422ARMZ-RL offers a wider supply range and lower noise, while the AD8420ARMZ provides a lower minimum supply voltage. Designers should validate supply headroom, power budget, and AC performance before substituting one for the other in a given application.
Supply Voltage Range
Validation required
Quiescent Current
Validation required
Package Type
High match
Gain Bandwidth Product
Validation required
Parts at a glance
Part B
AD8422ARMZ-RL
Компания Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 9502 ПКС
- Package
- TSSOP-8
- Series
- Линейные - Усилетели - Приборы, ОП Усилетели, Буферные Усилетели
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | AD8420ARMZ | AD8422ARMZ-RL | Why it matters |
|---|---|---|---|
| Amplifier Type | Instrumentation Amplifier (indirect current-mode) | Instrumentation Amplifier (3-op-amp) | The internal architecture determines noise, bandwidth, and input behavior, affecting whether the part can be dropped into an existing design. |
| Number of Channels | 1 | 1 | Both are single-channel in-amps, so channel count is compatible for direct substitution. |
| Supply Voltage Range | 2.7 V to 36 V (single) / ±1.35 V to ±18 V (dual) | 4.6 V to 36 V (single) / ±2.3 V to ±18 V (dual) | The AD8420 supports lower supply voltages, so it can operate in low-voltage systems where the AD8422 cannot. |
| Input Offset Voltage (max) | 250 µV | 70 µV | Lower offset improves DC accuracy; the AD8422 offers tighter offset for precision measurement applications. |
| Gain Range | 1 to 1000 (set by single resistor) | 1 to 1000 (set by single resistor) | Both allow resistor-programmable gain over the same range, supporting similar signal-conditioning flexibility. |
| Input Voltage Noise Density | 27 nV/√Hz (at 1 kHz) | 8 nV/√Hz (at 1 kHz) | Lower noise density benefits low-level signal amplification; the AD8422 is significantly quieter. |
| Bandwidth (−3 dB, G = 1) | 250 kHz | 2.2 MHz | Higher bandwidth supports faster signals; the AD8422 handles wider frequency content than the AD8420. |
| CMRR (G = 100) | 100 dB | 120 dB | Higher common-mode rejection improves accuracy in noisy environments; the AD8422 offers superior CMRR. |
| Quiescent Supply Current | 1.1 mA (typ) | 300 µA (typ) | Lower quiescent current extends battery life; the AD8422 is more power-efficient for portable designs. |
| Package | 8-Lead MSOP (ARMZ) | 8-Lead MSOP (ARMZ) | Identical package and pinout enable direct PCB footprint compatibility between the two parts. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | AD8420ARMZ | AD8422ARMZ-RL |
|---|---|---|
| Supplier | - | Analog Devices Inc. |
| 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 | 500 pA |
| Voltage - Input Offset | 250 µV | 70 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 AD8420ARMZ and AD8422ARMZ-RL?
The AD8420ARMZ is a micropower instrumentation amplifier with a supply current of approximately 85 µA and a gain bandwidth of 250 kHz, optimized for low-power portable applications. The AD8422ARMZ-RL is a high-performance instrumentation amplifier with 10 MHz gain bandwidth, 0.15 µV/°C offset drift, and 8 nV/√Hz input voltage noise, supplied in a 500-unit reel. The AD8420 prioritizes low supply current, while the AD8422 prioritizes AC performance and DC precision.
Are the AD8420ARMZ and AD8422ARMZ-RL pin-compatible?
Both devices are offered in an 8-lead MSOP (RMZ) package, but pin compatibility must be confirmed against the respective manufacturer datasheets. The AD8420 uses a standard instrumentation amplifier pinout with gain-setting via external resistors, while the AD8422 also uses external gain resistors. Designers should verify pin functions and any differences in the reference and gain-setting pins before considering a direct layout substitution.
Which device is better suited for low-power battery-operated designs?
The AD8420ARMZ is better suited for low-power designs. Its typical supply current is approximately 85 µA, making it appropriate for portable and battery-powered instrumentation. The AD8422ARMZ-RL draws significantly higher supply current (on the order of 1 mA typical) to support its 10 MHz bandwidth and low-noise performance, so it is less suitable for micropower applications.
How do the noise and bandwidth specifications compare?
The AD8422ARMZ-RL offers 10 MHz gain bandwidth and an input voltage noise density of approximately 8 nV/√Hz, making it suitable for precision, wide-bandwidth signal conditioning. The AD8420ARMZ has a gain bandwidth of approximately 250 kHz and higher input noise, reflecting its micropower design. For high-frequency or low-noise applications, the AD8422 is the stronger choice; for low-power applications, the AD8420 is preferred.
What is the significance of the "-RL" suffix on the AD8422ARMZ-RL?
The "-RL" suffix indicates a tape-and-reel packaging option. The AD8422ARMZ-RL is supplied in a 500-unit reel for automated assembly, whereas the AD8420ARMZ is typically supplied in tube or standard packaging. The electrical specifications of the AD8422ARMZ-RL are the same as the base AD8422ARMZ part; only the packaging quantity and form differ.
Can the AD8420ARMZ be used as a drop-in replacement for the AD8422ARMZ-RL?
No, they should not be treated as drop-in replacements. Although both are 8-lead MSOP instrumentation amplifiers, they differ in supply current, bandwidth, noise, and offset drift. A substitution requires revalidation of gain accuracy, bandwidth, noise budget, and power consumption against the target design requirements using the respective manufacturer datasheets.
What are the typical applications for each device?
The AD8420ARMZ is typically used in portable and battery-powered instrumentation, medical monitors, and low-power sensor interfaces where supply current is critical. The AD8422ARMZ-RL is used in precision data acquisition, industrial process control, and applications requiring low noise, low offset drift, and wider bandwidth. Selection should be based on the power, noise, and bandwidth requirements of the specific design.