Part A
AD8656ARMZ
아날로그 디바이스(주)
- Lifecycle
- Active
- Stock
- 7742 PCS
- Package
- MSOP-8
- Series
- 선형 증폭기 - 계측기, 연산 증폭기, 완충 증폭기
Replacement verdict
Compatible functional replacement candidate
The AD8656ARMZ and AD8655ARMZ-R2 are both dual-channel, low-noise, precision CMOS operational amplifiers from Analog Devices in the same 8-lead MSOP (RM) package, sharing identical pinout, supply range, and unity-gain stability. The AD8656ARMZ offers a higher gain-bandwidth product and faster slew rate, making it a viable functional upgrade in most AD8655ARMZ-R2 sockets, though the tighter input bias current and offset specifications of the AD8655ARMZ-R2 should be validated against application requirements before substitution.
Package and Pinout
High match
Channel Count and Function
High match
Supply Voltage Range
High match
Dynamic and DC Specifications
Validation required
Parts at a glance
Part B
AD8655ARMZ-R2
아날로그 디바이스(주)
- Lifecycle
- Active
- Stock
- 4035 PCS
- Package
- MSOP-8
- Series
- 선형 증폭기 - 계측기, 연산 증폭기, 완충 증폭기
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | AD8656ARMZ | AD8655ARMZ-R2 | Why it matters |
|---|---|---|---|
| Number of Amplifiers | 2 (Dual) | 1 (Single) | Channel count determines whether the part can serve multi-channel signal chains; a dual cannot directly replace a single in a one-channel layout without layout changes. |
| Input Voltage Noise Density | 2.8 nV/√Hz (typ) | 2.8 nV/√Hz (typ) | Low noise is critical for precision sensor and audio front-ends; matching noise performance preserves signal integrity in low-level applications. |
| Gain Bandwidth Product | 28 MHz (typ) | 28 MHz (typ) | GBW sets the achievable closed-loop bandwidth; identical values mean similar AC response and stability for a given gain configuration. |
| Supply Voltage Range | 2.7 V to 5.5 V | 2.7 V to 5.5 V | Compatible supply range ensures the part operates in the same rail-to-rail low-voltage systems without regulator changes. |
| Input Offset Voltage | 250 µV (max) | 250 µV (max) | Offset voltage directly affects DC accuracy; matching limits preserve precision in instrumentation and transducer interfaces. |
| Quiescent Current per Amplifier | 3.7 mA (typ) | 3.7 mA (typ) | Supply current impacts power budget and thermal design; equal per-amplifier current keeps power consumption predictable. |
| Package | 8-Lead MSOP | 8-Lead MSOP | Package footprint and pinout must match for drop-in board compatibility; identical packages simplify substitution. |
| Operating Temperature Range | -40 °C to +125 °C | -40 °C to +125 °C | Industrial temperature range ensures reliable operation across harsh environments; matching ranges preserve qualification status. |
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 | AD8656ARMZ | AD8655ARMZ-R2 |
|---|---|---|
| Series | DigiTrim® | DigiTrim® |
| Part Status | Active | Obsolete |
| Amplifier Type | CMOS | General Purpose |
| Number of Circuits | 2 | 1 |
| Output Type | Rail-to-Rail | Rail-to-Rail |
| Slew Rate | 11V/µs | 11V/µs |
| Gain Bandwidth Product | 28 MHz | 28 MHz |
| Current - Input Bias | 1 pA | 1 pA |
| Voltage - Input Offset | 50 µV | 50 µV |
| Supply Current | 3.7mA (x2 Channels) | 3.7mA |
| Current - Output / Channel | 220 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 AD8656ARMZ and AD8655ARMZ-R2?
Both are dual, low-noise, precision CMOS operational amplifiers from Analog Devices in an 8-lead MSOP (RM) package. The AD8656 is specified for a supply voltage range of 2.7 V to 5.5 V, while the AD8655 is specified for 2.7 V to 5.5 V as well but is characterized with tighter offset voltage and lower input bias current grades. The AD8655ARMZ-R2 is supplied in tape-and-reel packaging (R2 suffix), whereas the AD8656ARMZ is supplied in standard tube/rail packaging. Electrical parameters such as gain bandwidth (28 MHz typical) and voltage noise density (2.7 nV/√Hz typical) are shared across the family, but the AD8655 offers a lower maximum offset voltage than the AD8656.
Are the AD8656ARMZ and AD8655ARMZ-R2 pin-compatible?
Yes. Both devices are offered in the same 8-lead MSOP package with identical pin assignments (OUT A, -IN A, +IN A, V-, +IN B, -IN B, OUT B, V+). This allows them to share the same PCB footprint and land pattern.
Can the AD8656ARMZ be used as a direct drop-in replacement for the AD8655ARMZ-R2?
Pin compatibility and package compatibility are satisfied, but a direct drop-in replacement requires verifying that the AD8656's offset voltage, input bias current, and drift specifications meet the target design's error budget. The AD8655 provides tighter offset voltage limits than the AD8656, so substituting the AD8656 in a circuit designed around the AD8655's tighter DC precision may degrade accuracy. Always validate against the respective datasheets.
What is the difference between the ARMZ and ARMZ-R2 suffixes?
The "ARMZ" suffix denotes the 8-lead MSOP package in standard packaging (typically tube or rail). The "ARMZ-R2" suffix denotes the same 8-lead MSOP package but supplied in tape-and-reel format (R2 indicates the reel quantity option). The silicon die and electrical specifications are unchanged by the packaging suffix.
What supply voltage range do the AD8656ARMZ and AD8655ARMZ-R2 support?
Both devices operate from a single supply of 2.7 V to 5.5 V, and they are also specified for dual-supply operation within the same total range (for example, ±1.35 V to ±2.75 V). They are rail-to-rail input and output CMOS amplifiers suitable for low-voltage precision signal conditioning.
What are the typical gain bandwidth and voltage noise specifications for these amplifiers?
Both the AD8656 and AD8655 are specified with a typical gain bandwidth product of 28 MHz and a typical input voltage noise density of 2.7 nV/√Hz at 1 kHz. These low-noise, high-bandwidth characteristics make them suitable for precision instrumentation, ADC driving, and audio signal chains.
Do the AD8656ARMZ and AD8655ARMZ-R2 differ in offset voltage specifications?
Yes. The AD8655 is offered with a lower maximum input offset voltage than the AD8656. The AD8655 datasheet specifies a maximum offset voltage of 250 µV, while the AD8656 specifies a maximum offset voltage of 500 µV. Designers requiring tighter DC precision should select the AD8655 grade and confirm the exact limits in the manufacturer datasheet for the specific temperature range.
Are the AD8656ARMZ and AD8655ARMZ-R2 RoHS compliant?
Yes. Both the AD8656ARMZ and AD8655ARMZ-R2 are RoHS-compliant parts per Analog Devices' product documentation. The "Z" in the suffix indicates a lead-free, RoHS-compliant package finish. Confirm compliance status on the manufacturer or authorized distributor listing for the specific orderable part number.