Part A
ADA4666-2ARMZ
Analog Equipment GmbH.
- Lifecycle
- Active
- Stock
- 7397 PCS
- Series
- Amplificateurs linéaires - instruments, amplificateurs opérationnels, amplificateurs tampons
Replacement verdict
Compatible functional replacement candidate
The ADA4666-2ARMZ is a viable functional replacement candidate for the ADA4661-2ARMZ-RL in many dual op-amp applications, sharing the same MSOP-8 package and similar supply voltage range, though the designer must validate bandwidth, supply current, and offset voltage against the target circuit requirements before committing to the substitution.
Package Type
High match
Supply Voltage Range
High match
Gain Bandwidth Product
Validation required
Supply Current per Amplifier
Validation required
Parts at a glance
Part B
ADA4661-2ARMZ-RL
Analog Equipment GmbH.
- Lifecycle
- Active
- Stock
- 3689 PCS
- Package
- MSOP-8
- Series
- Amplificateurs linéaires - instruments, amplificateurs opérationnels, amplificateurs tampons
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | ADA4661-2ARMZ-RL | ADA4666-2ARMZ | Why it matters |
|---|---|---|---|
| Number of Amplifiers | 2 | 2 | Both are dual op-amps, so channel count is compatible for dual-channel signal chains. |
| Supply Voltage Range | 4 V to 18 V | 2.7 V to 5.5 V | The ADA4661-2 supports higher supply rails, while the ADA4666-2 is limited to low-voltage systems; this affects direct substitutability in a given rail design. |
| Input Offset Voltage (Max) | 0.15 mV | 0.5 mV | Lower offset voltage improves DC precision; the ADA4661-2 offers tighter offset for precision applications. |
| Input Bias Current (Typ) | 1 pA | 1 pA | Very low input bias current is critical for high-impedance sensor interfaces; both parts are comparable here. |
| Gain Bandwidth Product | 2 MHz | 1 MHz | GBW determines the achievable closed-loop bandwidth; the ADA4661-2 provides roughly twice the bandwidth. |
| Slew Rate | 1 V/µs | 0.5 V/µs | Slew rate limits large-signal response speed; the ADA4661-2 responds faster to fast transients. |
| Supply Current per Amplifier (Typ) | 0.58 mA | 0.14 mA | Quiescent current affects power budget; the ADA4666-2 is significantly lower power, important for battery-operated designs. |
| Input Voltage Noise Density (1 kHz) | 22 nV/√Hz | 30 nV/√Hz | Lower noise density improves signal-to-noise ratio in low-level signal amplification; the ADA4661-2 is quieter. |
| Operating Temperature Range | -40 °C to +125 °C | -40 °C to +125 °C | Both support industrial temperature ranges, so environmental compatibility is equivalent. |
| Package | 8-Lead MSOP (RM) | 8-Lead MSOP (RM) | Identical package and pinout allow drop-in PCB compatibility between the two parts. |
Need help validating a replacement?
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | ADA4666-2ARMZ | ADA4661-2ARMZ-RL |
|---|---|---|
| Part Status | Active | Active |
| Amplifier Type | CMOS | CMOS |
| Number of Circuits | 2 | 2 |
| Output Type | Rail-to-Rail | Rail-to-Rail |
| Slew Rate | 2V/µs | 2V/µs |
| Gain Bandwidth Product | 4 MHz | 4 MHz |
| -3 dB Bandwidth | 2.1 MHz | 2.1 MHz |
| Current - Input Bias | 0.5 pA | 0.5 pA |
| Voltage - Input Offset | 500 µV | 30 µV |
| Supply Current | 630µA (x2 Channels) | 630µA (x2 Channels) |
| Current - Output / Channel | 220 mA | 220 mA |
| Voltage - Supply Span(Min) | 3 V | 3 V |
| Voltage - Supply Span(Max) | 18 V | 18 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 ADA4661-2ARMZ-RL and the ADA4666-2ARMZ?
Both are dual, low-power operational amplifiers from Analog Devices in an 8-lead MSOP (ARMZ) package. The ADA4661-2 is a precision, low-noise, rail-to-rail input/output CMOS amplifier optimized for low offset voltage and drift, while the ADA4666-2 is a lower-power, lower-cost CMOS amplifier with wider bandwidth but less stringent DC precision. The ADA4661-2ARMZ-RL is supplied in tape-and-reel packaging, whereas the ADA4666-2ARMZ is typically supplied in tube or standard reel packaging depending on the ordering variant.
Are the ADA4661-2ARMZ-RL and ADA4666-2ARMZ pin-compatible?
Yes. Both devices use the standard dual op-amp pinout in an 8-lead MSOP package, with the same pin functions (OUT A, -IN A, +IN A, V-, +IN B, -IN B, OUT B, V+). This allows them to share the same PCB footprint, but electrical differences must still be validated before substitution.
How do the supply voltage ranges of the ADA4661-2 and ADA4666-2 compare?
Both amplifiers operate from a single supply of 2.7 V to 5.5 V (or dual supplies of ±1.35 V to ±2.75 V), making them suitable for low-voltage portable and battery-powered systems. Designers should confirm the exact supply range against the respective manufacturer datasheet for the specific grade ordered.
Which device offers lower input offset voltage for precision applications?
The ADA4661-2 is specified with a lower input offset voltage and lower offset voltage drift than the ADA4666-2, making it the preferred choice for precision signal conditioning, sensor interfaces, and low-error DC amplification. The ADA4666-2 is better suited to applications where bandwidth and power consumption are prioritized over tight DC accuracy.
How do the quiescent currents of the ADA4661-2 and ADA4666-2 differ?
The ADA4666-2 is designed for lower quiescent current per amplifier than the ADA4661-2, making it advantageous in power-sensitive, always-on, or battery-operated designs. The ADA4661-2 trades some supply current for improved precision and lower noise. Exact quiescent current values should be verified from the manufacturer datasheets for the specific operating conditions.
Can the ADA4666-2ARMZ be used as a drop-in replacement for the ADA4661-2ARMZ-RL?
Pin compatibility allows a physical drop-in, but a functional drop-in requires validating offset voltage, offset drift, noise, bandwidth, slew rate, and quiescent current against the target design requirements. If the application depends on the ADA4661-2's tighter DC precision or lower noise, the ADA4666-2 may not meet specifications and should not be substituted without verification.
What are the packaging and ordering differences between the ADA4661-2ARMZ-RL and ADA4666-2ARMZ?
Both are offered in the 8-lead MSOP (ARMZ) package. The ADA4661-2ARMZ-RL suffix indicates tape-and-reel packaging intended for automated assembly. The ADA4666-2ARMZ designation refers to the MSOP package variant; reel or tube options are determined by the specific orderable part number. Buyers should confirm the packaging quantity and orientation from the distributor or manufacturer ordering guide.
Which amplifier is better suited for low-noise audio or sensor front-end designs?
The ADA4661-2 is specified with lower voltage noise and lower offset voltage than the ADA4666-2, making it more suitable for low-noise sensor front-ends and precision signal chains. The ADA4666-2 is generally chosen where lower power consumption and adequate bandwidth are the dominant requirements rather than lowest noise.