Part A
AD8655ARZ
Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 7253 Stückzahl
- Package
- SOIC-8
- Series
- Linear-Verstärker.Instrumentation, OP-Verstärker, Pufferverstärker
Replacement verdict
Compatible functional replacement candidate
The AD8655ARZ is a viable functional replacement candidate for the AD8651ARZ, sharing the same CMOS op-amp architecture, SOIC-8 package, and single-supply operating range. Designers should validate bandwidth, noise, and drive characteristics against the specific application requirements before substituting.
Package Type
High match
Supply Voltage Range
High match
Gain Bandwidth Product
Validation required
Input Voltage Noise
Validation required
Parts at a glance
Part B
AD8651ARZ
Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 4971 Stückzahl
- Package
- SOIC-8
- 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 | AD8651ARZ | AD8655ARZ | Why it matters |
|---|---|---|---|
| Number of Amplifiers | 1 | 1 | Both are single-channel op-amps, so channel count is compatible for direct substitution. |
| Supply Voltage Range | 2.7 V to 5.5 V | 2.7 V to 5.5 V | Identical supply range ensures the part can operate in the same power rail conditions. |
| Gain Bandwidth Product | 50 MHz | 28 MHz | Higher GBW in the AD8651 supports wider-bandwidth signal processing; a lower-GBW substitute may limit AC performance. |
| Input Voltage Noise Density | 5 nV/√Hz | 10 nV/√Hz | Lower noise density improves signal-to-noise ratio in precision and low-level signal applications. |
| Quiescent Current (per amplifier) | 9.5 mA | 3.7 mA | Lower quiescent current in the AD8655 reduces power consumption, important for battery-powered designs. |
| Slew Rate | 41 V/µs | 22 V/µs | Slew rate affects large-signal transient response; the AD8651 handles faster signal edges. |
| Input Offset Voltage (max) | 250 µV | 250 µV | Matching offset voltage ensures comparable DC accuracy in precision measurement circuits. |
| Rail-to-Rail Input/Output | Yes | Yes | Both support rail-to-rail I/O, allowing full dynamic range utilization on the same supply. |
| Package | 8-Lead SOIC | 8-Lead SOIC | Identical package and pinout enable drop-in board replacement without layout changes. |
| Operating Temperature Range | -40 °C to +125 °C | -40 °C to +125 °C | Same temperature range ensures equivalent environmental robustness for industrial applications. |
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 | AD8655ARZ | AD8651ARZ |
|---|---|---|
| Series | DigiTrim® | DigiTrim® |
| Part Status | Active | Active |
| Amplifier Type | General Purpose | Voltage Feedback |
| Number of Circuits | 1 | 1 |
| Output Type | Rail-to-Rail | Rail-to-Rail |
| Slew Rate | 11V/µs | 41V/µs |
| Gain Bandwidth Product | 28 MHz | 50 MHz |
| Current - Input Bias | 1 pA | 1 pA |
| Voltage - Input Offset | 50 µV | 100 µV |
| Supply Current | 3.7mA | 9.5mA |
| Current - Output / Channel | 220 mA | 40 mA |
| Voltage - Supply Span(Min) | 2.7 V | 2.7 V |
| Voltage - Supply Span(Max) | 5.5 V | 5.5 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 AD8651ARZ and AD8655ARZ operational amplifiers?
The AD8651ARZ is a single-channel, 50 MHz rail-to-rail input/output CMOS op amp optimized for low voltage (2.7 V to 5.5 V) operation with a typical quiescent current of 4.5 mA. The AD8655ARZ is a single-channel, 28 MHz rail-to-rail input/output CMOS op amp with lower typical quiescent current of 3.5 mA and lower typical voltage noise of 5 nV/√Hz. Both are offered in an 8-lead SOIC package.
Are the AD8651ARZ and AD8655ARZ pin-compatible?
Yes. Both devices are single operational amplifiers supplied in an 8-lead SOIC (R-8) package with the same pinout: pin 1 and 5 are null, pin 2 is -IN, pin 3 is +IN, pin 4 is V-, pin 6 is OUT, pin 7 is V+, and pin 8 is NC. This allows the two parts to share the same PCB footprint, though electrical differences must still be validated for the target design.
How do the gain-bandwidth and slew rate of the AD8651ARZ and AD8655ARZ compare?
The AD8651ARZ has a typical gain-bandwidth product of 50 MHz and a typical slew rate of 41 V/µs. The AD8655ARZ has a typical gain-bandwidth product of 28 MHz and a typical slew rate of 22 V/µs. The AD8651ARZ therefore offers higher speed, while the AD8655ARZ trades bandwidth for lower noise and lower supply current.
Which device has lower voltage noise, the AD8651ARZ or the AD8655ARZ?
The AD8655ARZ has lower voltage noise, with a typical value of 5 nV/√Hz at 1 kHz. The AD8651ARZ has a typical voltage noise of 6.5 nV/√Hz at 1 kHz. For low-noise signal conditioning, the AD8655ARZ is generally the better choice when bandwidth requirements permit.
What are the supply voltage and quiescent current specifications for these two amplifiers?
Both the AD8651ARZ and AD8655ARZ operate from a single supply of 2.7 V to 5.5 V. The AD8651ARZ has a typical quiescent current of 4.5 mA per amplifier, while the AD8655ARZ has a typical quiescent current of 3.5 mA per amplifier. The AD8655ARZ is therefore more power-efficient in always-on or battery-powered applications.
Can the AD8651ARZ and AD8655ARZ be used in the same circuit without redesign?
Because both parts share the same 8-lead SOIC pinout and the same 2.7 V to 5.5 V supply range, they can often be evaluated in the same socket. However, the differences in gain-bandwidth product (50 MHz vs. 28 MHz), slew rate (41 V/µs vs. 22 V/µs), voltage noise (6.5 nV/√Hz vs. 5 nV/√Hz), and quiescent current (4.5 mA vs. 3.5 mA) mean that loop stability, compensation, and AC performance must be re-verified before substituting one for the other in a production design.
What input bias current and offset voltage performance do the AD8651ARZ and AD8655ARZ provide?
Both devices are CMOS rail-to-rail input/output amplifiers with very low input bias current, typically in the low picoampere range, making them suitable for high-impedance sensor interfaces. The AD8651ARZ specifies a typical input offset voltage of 100 µV, while the AD8655ARZ specifies a typical input offset voltage of 50 µV. Exact limits should be confirmed against the respective manufacturer datasheets for the required grade and temperature range.
Which applications are best suited to the AD8651ARZ versus the AD8655ARZ?
The AD8651ARZ, with its 50 MHz gain-bandwidth and 41 V/µs slew rate, is better suited to higher-speed signal chains such as active filters, ADC drivers, and fast transimpedance stages. The AD8655ARZ, with its lower 5 nV/√Hz noise and lower 3.5 mA quiescent current, is better suited to precision low-noise sensor amplification, portable instrumentation, and power-sensitive analog front ends where 28 MHz bandwidth is sufficient.