Part A
ADA4666-2ARMZ
Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 7397 Stückzahl
- Series
- Linear-Verstärker.Instrumentation, OP-Verstärker, Pufferverstärker
Replacement verdict
Compatible functional replacement candidate
The ADA4666-2ARMZ is a viable functional replacement candidate for the ADA4661-2ARMZ in many dual op-amp applications, sharing the same MSOP-8 package and dual-channel configuration. However, designers must validate supply voltage headroom, input bias current, and bandwidth requirements against the target circuit, since the two devices differ in these electrical characteristics.
Package Type
High match
Channel Count
High match
Supply Voltage Range
Validation required
Input Bias Current
Validation required
Parts at a glance
Part B
ADA4661-2ARMZ
Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 2207 Stückzahl
- Series
- Linear-Verstärker.Instrumentation, OP-Verstärker, Pufferverstärker
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 | ADA4666-2ARMZ | Why it matters |
|---|---|---|---|
| Supply Voltage Range | 4 V to 18 V | 2.7 V to 5.5 V | Determines compatibility with the system power rail; the ADA4661-2 supports high-voltage rails while the ADA4666-2 is limited to low-voltage rails, so they are not drop-in replacements in high-voltage designs. |
| Input Offset Voltage (max) | 0.15 mV | 0.5 mV | Lower offset improves DC accuracy in precision signal chains; the ADA4661-2 offers tighter offset, which matters for high-accuracy amplification. |
| Input Bias Current (typ) | 0.5 pA | 1 pA | Very low bias current minimizes errors in high-impedance sensor interfaces; both are excellent, but the ADA4661-2 is slightly better for ultra-high-impedance nodes. |
| Gain Bandwidth Product | 2 MHz | 1.8 MHz | GBW sets the achievable closed-loop bandwidth; the ADA4661-2 provides slightly more bandwidth for faster signal processing. |
| Supply Current per Amplifier (typ) | 0.58 mA | 0.35 mA | Quiescent current affects power budget; the ADA4666-2 draws less current, making it preferable for low-power portable designs. |
| Input Voltage Noise Density (1 kHz) | 22 nV/√Hz | 25 nV/√Hz | Lower noise density improves SNR in low-level signal amplification; the ADA4661-2 offers marginally better noise performance. |
| Number of Amplifiers | 2 | 2 | Both are dual op-amps, so channel count is identical and does not affect substitutability. |
| Package | 8-Lead MSOP (ARMZ) | 8-Lead MSOP (ARMZ) | Identical package and pinout allow direct PCB footprint compatibility between the two parts. |
| Rail-to-Rail Input/Output | Rail-to-Rail Input and Output | Rail-to-Rail Input and Output | Both support rail-to-rail swing, maximizing dynamic range; this is a shared strength relevant to low-voltage signal conditioning. |
| Operating Temperature Range | -40 °C to +125 °C | -40 °C to +125 °C | Identical industrial/extended temperature range ensures both parts suit harsh environments equally. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | ADA4666-2ARMZ | ADA4661-2ARMZ |
|---|---|---|
| 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 and ADA4666-2ARMZ operational amplifiers?
Both are dual, precision, low-power CMOS operational amplifiers from Analog Devices in an 8-lead MSOP (ARMZ) package. The ADA4661-2 is specified with a typical offset voltage of 50 µV (150 µV max) and a typical input bias current of 1 pA, while the ADA4666-2 is specified with a typical offset voltage of 100 µV (250 µV max) and a typical input bias current of 1 pA. The ADA4661-2 offers a typical unity-gain bandwidth of 4 MHz versus 2 MHz for the ADA4666-2, and a typical slew rate of 2 V/µs versus 1 V/µs. Both operate from a single supply of 2.7 V to 5.5 V (or dual ±1.35 V to ±2.75 V) and are specified over the −40 °C to +125 °C temperature range.
Are the ADA4661-2ARMZ and ADA4666-2ARMZ pin-compatible?
Yes. Both devices are offered in the same 8-lead MSOP (ARMZ) package with identical pin assignments: pin 1 = OUT A, pin 2 = −IN A, pin 3 = +IN A, pin 4 = V−, pin 5 = +IN B, pin 6 = −IN B, pin 7 = OUT B, and pin 8 = V+. This allows the two parts to share the same PCB footprint and land pattern.
Can the ADA4666-2ARMZ be used as a drop-in replacement for the ADA4661-2ARMZ?
Pin compatibility and shared supply range (2.7 V to 5.5 V) permit a physical drop-in, but the ADA4666-2 has lower bandwidth (2 MHz vs 4 MHz typical), lower slew rate (1 V/µs vs 2 V/µs typical), and higher offset voltage (100 µV vs 50 µV typical). Circuit performance in gain, settling, and DC accuracy must be revalidated against the ADA4666-2 datasheet before substitution.
What is the supply voltage range for the ADA4661-2ARMZ and ADA4666-2ARMZ?
Both amplifiers are specified for operation from a single supply of 2.7 V to 5.5 V, or from dual supplies of ±1.35 V to ±2.75 V. They are specified over the −40 °C to +125 °C industrial temperature range.
How do the quiescent supply currents of the ADA4661-2ARMZ and ADA4666-2ARMZ compare?
Both devices are low-power CMOS amplifiers with a typical quiescent supply current of approximately 500 µA per amplifier (1 mA total for the dual) at 5 V. The ADA4666-2 is positioned as a lower-bandwidth, lower-power alternative, and its datasheet should be consulted for the exact specified maximum supply current over temperature.
Which applications are better suited to the ADA4661-2ARMZ versus the ADA4666-2ARMZ?
The ADA4661-2ARMZ, with its higher 4 MHz typical unity-gain bandwidth, 2 V/µs typical slew rate, and lower 50 µV typical offset, is better suited to higher-speed signal conditioning, active filtering, and precision sensor interfaces. The ADA4666-2ARMZ, with 2 MHz typical bandwidth and 1 V/µs typical slew rate, is better suited to lower-power, lower-bandwidth precision applications such as portable instrumentation and battery-powered sensor front ends where reduced dynamic performance is acceptable.
Do the ADA4661-2ARMZ and ADA4666-2ARMZ support rail-to-rail input and output operation?
Yes. Both are rail-to-rail input and output (RRIO) CMOS operational amplifiers, allowing input common-mode voltage and output swing to extend to the supply rails, which maximizes dynamic range in low-voltage single-supply designs.