Part A
AD8646ARZ
ADI公司
- Lifecycle
- Active
- Stock
- 5091 件
- Package
- SOIC-8
- Series
- 線性放大器-儀器、運算放大器、緩衝放大器
Replacement verdict
Compatible functional replacement candidate
The AD8641ARZ and AD8646ARZ share the same SOIC-8 package, single-supply operating range, and rail-to-rail output architecture, making the AD8646ARZ a viable functional substitute for the AD8641ARZ in many low-power signal-conditioning designs. However, the AD8646ARZ is a dual-channel device with higher quiescent current and wider gain-bandwidth product, so the replacement must be validated against the original circuit's power budget, channel count, and dynamic requirements before adoption.
Package Type
High match
Channel Count
Validation required
Supply Current
Validation required
Gain Bandwidth Product
High match
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | AD8641ARZ | AD8646ARZ | Why it matters |
|---|---|---|---|
| Number of Amplifiers | 1 | 2 | Determines how many independent signal channels can be processed in one package; a single vs dual configuration directly affects circuit architecture and board space. |
| Input Offset Voltage (max) | 250 µV | 600 µV | Lower offset voltage improves DC precision; a significant difference affects accuracy in precision signal-conditioning applications. |
| Input Bias Current (typ) | 0.25 pA | 0.3 pA | Ultra-low bias current is critical for high-impedance sensor interfaces; small differences can matter in femtoampere-sensitive designs. |
| Gain Bandwidth Product | 3.5 MHz | 24 MHz | GBW sets the achievable closed-loop bandwidth; the much higher GBW of the dual part enables faster signal processing and higher-frequency applications. |
| Slew Rate | 3 V/µs | 11 V/µs | Slew rate limits large-signal response speed; a higher slew rate supports faster transient response and wider large-signal bandwidth. |
| Supply Current per Amplifier (typ) | 200 µA | 1.5 mA | Quiescent current drives power budget; the lower-current single amplifier suits battery-powered or low-power designs, while the dual part trades power for speed. |
| Supply Voltage Range | 5 V to 26 V | 5 V to 26 V | Identical operating supply range means both parts are interchangeable from a power-rail perspective in the same system. |
| Input Voltage Noise Density (1 kHz) | 28 nV/√Hz | 28 nV/√Hz | Matching noise performance means similar signal-to-noise behavior in low-level signal applications, supporting functional substitutability. |
| Package | 8-Lead SOIC | 8-Lead SOIC | Same package footprint allows drop-in board compatibility, though pinout differs between single and dual amplifier configurations. |
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 | AD8646ARZ | AD8641ARZ |
|---|---|---|
| Part Status | Active | Active |
| Amplifier Type | General Purpose | J-FET |
| Number of Circuits | 2 | 1 |
| Output Type | Rail-to-Rail | Rail-to-Rail |
| Slew Rate | 11V/µs | 3V/µs |
| Gain Bandwidth Product | 24 MHz | 3.5 MHz |
| Current - Input Bias | 0.3 pA | 0.25 pA |
| Voltage - Input Offset | 600 µV | 70 µV |
| Supply Current | 1.5mA (x2 Channels) | 200µA |
| Current - Output / Channel | 120 mA | 12 mA |
| Voltage - Supply Span(Min) | 2.7 V | 5 V |
| Voltage - Supply Span(Max) | 5.5 V | 26 V |
| Operating Temperature | -40°C ~ 125°C | -40°C ~ 125°C |
| Mounting Type | Surface Mount | Surface Mount |
Frequently asked questions
What are the primary differences between the AD8641ARZ and AD8646ARZ?
The AD8641ARZ is a single, low-power, precision JFET-input operational amplifier, while the AD8646ARZ is a dual, low-power, precision JFET-input operational amplifier. Both are offered in an 8-lead SOIC package, but the AD8646ARZ integrates two amplifiers in the same footprint, whereas the AD8641ARZ contains one amplifier with dedicated nulling or compensation pins depending on the exact grade.
Are the AD8641ARZ and AD8646ARZ pin-compatible in an 8-lead SOIC package?
No. Although both devices use an 8-lead SOIC (R-8) package, their pinouts differ. The AD8641ARZ single amplifier uses the standard single-op-amp pinout with offset null or compensation pins, while the AD8646ARZ dual amplifier uses the standard dual-op-amp pinout with two independent amplifier sections. A direct drop-in replacement is not possible without verifying the pin functions against the respective datasheets.
Do the AD8641ARZ and AD8646ARZ share the same supply voltage range?
Yes. Both the AD8641ARZ and AD8646ARZ are specified for operation from a single supply of 5 V to 26 V, or a dual supply of ±2.5 V to ±13 V, per the Analog Devices datasheets. Designers should still confirm the exact grade and test conditions in the manufacturer documentation before finalizing the supply rail.
How do the input bias current and input offset voltage compare between the two parts?
Both devices are JFET-input amplifiers with very low input bias current, typically in the picoampere range, and low input offset voltage. The AD8641ARZ is specified with a maximum input offset voltage of 250 µV (B grade) and the AD8646ARZ with a maximum of 600 µV (B grade), depending on the exact grade. The AD8641ARZ offers tighter offset voltage specifications, making it preferable for higher-precision single-channel designs.
Can the AD8646ARZ replace the AD8641ARZ in an existing single-amplifier circuit?
Not directly. The AD8646ARZ is a dual amplifier with a different pinout, so replacing a single AD8641ARZ requires re-routing the PCB to use one of the two amplifier sections and leaving the other section properly terminated. Electrical performance is similar, but the pin configuration and channel count differ, so the substitution must be validated against the manufacturer datasheet and the target design.
What are the typical quiescent supply currents of the AD8641ARZ and AD8646ARZ?
The AD8641ARZ typically draws about 200 µA per amplifier, and the AD8646ARZ typically draws about 200 µA per amplifier as well, for a total of approximately 400 µA for the dual device. These low quiescent currents make both parts suitable for battery-powered and portable precision signal-conditioning applications.
Which applications are best suited to the AD8641ARZ versus the AD8646ARZ?
The AD8641ARZ is well suited to single-channel precision applications such as high-impedance sensor interfaces, photodiode transimpedance amplifiers, and precision filters where tight offset voltage is critical. The AD8646ARZ is better suited to dual-channel designs such as two-stage signal chains, differential or instrumentation front ends, and multi-channel sensor conditioning where board space and channel count matter.
Are the AD8641ARZ and AD8646ARZ specified over the same temperature range?
Yes. Both the AD8641ARZ and AD8646ARZ are specified for the industrial temperature range of −40 °C to +125 °C, per the Analog Devices datasheets. Designers should verify the exact grade and package suffix in the manufacturer documentation to confirm the operating temperature range for the specific orderable part number.