Part A
AD8651ARMZ
Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 6670 PCS
- Package
- MSOP-8
- Series
- Linear - Amplificadores - Instrumentação, OP Amps, Buffer Amps
Replacement verdict
Compatible functional replacement candidate
The AD8655ARMZ-R2 is a viable functional replacement candidate for the AD8651ARMZ, sharing the same MSOP-8 footprint, single-supply operating range, and CMOS rail-to-rail input/output architecture. Designers should validate bandwidth, noise, and drive characteristics against the specific application requirements before committing to substitution.
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
AD8655ARMZ-R2
Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 4035 PCS
- Package
- MSOP-8
- Series
- Linear - Amplificadores - Instrumentação, OP Amps, Buffer Amps
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | AD8651ARMZ | AD8655ARMZ-R2 | Why it matters |
|---|---|---|---|
| Input Voltage Noise Density | 5 nV/√Hz (typ) | 2.7 nV/√Hz (typ) | Lower noise density improves signal-to-noise ratio in precision and low-level signal applications, making the AD8655 preferable for sensitive front-ends. |
| Gain Bandwidth Product | 50 MHz | 28 MHz | GBW determines the maximum frequency at which the amplifier can provide useful gain; the AD8651 supports higher-bandwidth signal chains. |
| Supply Current per Amplifier | 9.5 mA (typ) | 3.7 mA (typ) | Quiescent current directly affects power budget; the AD8655 is significantly more power-efficient for battery-powered or dense designs. |
| Slew Rate | 41 V/µs | 22 V/µs | Slew rate limits large-signal dynamic response; the AD8651 handles faster transients and higher-frequency large signals. |
| Input Offset Voltage | 250 µV (max) | 250 µV (max) | Offset voltage affects DC accuracy; both parts share the same maximum offset specification, so DC precision is comparable. |
| Supply Voltage Range | 2.7 V to 5.5 V | 2.7 V to 5.5 V | Identical supply range means both parts are interchangeable in single-supply systems operating from 3 V or 5 V rails. |
| Number of Amplifiers | 1 (single) | 1 (single) | Channel count must match the circuit topology; both are single amplifiers, so package pinout and channel usage are compatible. |
| Package | 8-Lead MSOP | 8-Lead MSOP | Same package and pinout allow drop-in replacement on an existing PCB without layout changes. |
| Operating Temperature Range | -40 °C to +125 °C | -40 °C to +125 °C | Matching temperature ratings ensure both parts meet the same environmental requirements for industrial and automotive 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 | AD8651ARMZ | AD8655ARMZ-R2 |
|---|---|---|
| Series | DigiTrim® | DigiTrim® |
| Part Status | Active | Obsolete |
| Amplifier Type | Voltage Feedback | General Purpose |
| Number of Circuits | 1 | 1 |
| Output Type | Rail-to-Rail | Rail-to-Rail |
| Slew Rate | 41V/µs | 11V/µs |
| Gain Bandwidth Product | 50 MHz | 28 MHz |
| Current - Input Bias | 1 pA | 1 pA |
| Voltage - Input Offset | 100 µV | 50 µV |
| Supply Current | 9.5mA | 3.7mA |
| Current - Output / Channel | 40 mA | 220 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 key differences between the AD8651ARMZ and AD8655ARMZ-R2?
The AD8651ARMZ is a single-channel, 50 MHz, low-noise, precision CMOS operational amplifier in an 8-lead MSOP package. The AD8655ARMZ-R2 is a single-channel, 28 MHz, low-noise, precision CMOS op amp also in an 8-lead MSOP package, supplied on a 250-unit reel. The primary differences are bandwidth (50 MHz vs. 28 MHz), slew rate, and packaging/reel configuration.
Are the AD8651ARMZ and AD8655ARMZ-R2 pin-compatible?
Yes. Both devices are offered in the same 8-lead MSOP (RM) package and share the standard single op amp pinout, so they are pin-compatible when the package and pinout match the datasheet.
Can the AD8651ARMZ be used as a drop-in replacement for the AD8655ARMZ-R2?
Not unconditionally. Although pin-compatible, the AD8651ARMZ has higher gain bandwidth (50 MHz vs. 28 MHz) and a different slew rate, which can affect stability, compensation, and power consumption in a given circuit. The replacement should be validated against the AD8651 datasheet and the target design requirements.
What is the supply voltage range for these op amps?
Both the AD8651 and AD8655 are specified for single-supply operation from 2.7 V to 5.5 V, making them suitable for low-voltage precision signal conditioning applications.
How do the noise specifications compare between the AD8651ARMZ and AD8655ARMZ-R2?
Both are low-noise CMOS op amps. The AD8651 is specified with a low voltage noise density of approximately 5 nV/√Hz, and the AD8655 is similarly specified as a low-noise precision amplifier. For exact noise density and 1/f corner values, refer to the respective manufacturer datasheets.
What is the difference in the "-R2" suffix on the AD8655ARMZ-R2?
The "-R2" suffix denotes the packaging/reel option. The AD8655ARMZ-R2 is supplied on a 250-unit reel, whereas the AD8651ARMZ is typically supplied in standard tube or reel quantities per the manufacturer's ordering guide. The electrical performance of the device is unaffected by the reel suffix.
Which device is better suited for higher-bandwidth applications?
The AD8651ARMZ, with its 50 MHz gain bandwidth product, is better suited for higher-bandwidth signal chains than the AD8655ARMZ-R2, which has a 28 MHz gain bandwidth product. Selection should still account for stability, load capacitance, and supply current in the target circuit.