Part A
AD8656ARMZ
テキサス・インスツルメンツ
- Lifecycle
- Active
- Stock
- 7742 個数
- Package
- MSOP-8
- Series
- リニアアンプ - 計装用、オペアンプ、バッファアンプ
Replacement verdict
Compatible functional replacement candidate
The AD8657ARMZ-R7 and AD8656ARMZ are both dual-channel, low-noise CMOS operational amplifiers in the same 8-lead MSOP (RM-8) package, sharing a common footprint and pinout that make them strong functional replacement candidates. The AD8657ARMZ-R7 is specified for lower supply voltage operation and reduced quiescent current, while the AD8656ARMZ offers higher bandwidth and faster slew rate. Designers should validate supply voltage headroom, dynamic performance, and thermal margins against the target application before final substitution.
Package and Pinout
High match
Channel Count and Amplifier Type
High match
Supply Voltage Range
Validation required
Dynamic Performance
Validation required
Parts at a glance
Part B
AD8657ARMZ-R7
テキサス・インスツルメンツ
- Lifecycle
- Active
- Stock
- 2910 個数
- Package
- MSOP-8
- Series
- リニアアンプ - 計装用、オペアンプ、バッファアンプ
Key differences
Rows are prioritized by design impact. Highlighted values require attention during substitution.
Key electrical and mechanical differences between the two devices
| Parameter | AD8657ARMZ-R7 | AD8656ARMZ | Why it matters |
|---|---|---|---|
| Number of Amplifiers | 2 | 2 | Both are dual op-amps, so channel count is identical and does not affect substitutability. |
| Supply Voltage Range | 2.7 V to 5.5 V | 2.7 V to 5.5 V | Matching supply ranges ensure the parts can drop into the same rail configuration without rework. |
| Input Offset Voltage (Max) | 250 µV | 250 µV | Offset voltage directly affects DC accuracy; identical limits mean comparable precision in signal chains. |
| Input Bias Current (Typ) | 1 pA | 1 pA | Very low bias current suits high-impedance sensor interfaces; matching values preserve input loading behavior. |
| Gain Bandwidth Product | 2.7 MHz | 28 MHz | GBW sets the achievable closed-loop bandwidth; the large difference means the AD8656 supports much faster signal processing. |
| Slew Rate | 1.2 V/µs | 11 V/µs | Slew rate limits large-signal response; the AD8656 handles faster transients and higher-frequency large signals. |
| Quiescent Current per Amplifier (Typ) | 18 µA | 2.3 mA | Quiescent current drives power budget; the AD8657 is far lower power, critical for battery-operated designs. |
| Input Voltage Noise Density (Typ) | 22 nV/√Hz | 2.7 nV/√Hz | Lower noise density improves SNR in precision sensing; the AD8656 is significantly quieter for low-level signals. |
| Package / Mounting | 8-Lead MSOP, Surface Mount | 8-Lead MSOP, Surface Mount | Identical package and footprint allow direct PCB replacement without layout changes. |
Need help validating a replacement?
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | AD8656ARMZ | AD8657ARMZ-R7 |
|---|---|---|
| Series | DigiTrim® | - |
| Part Status | Active | Active |
| Amplifier Type | CMOS | CMOS |
| Number of Circuits | 2 | 2 |
| Output Type | Rail-to-Rail | Rail-to-Rail |
| Slew Rate | 11V/µs | 0.08V/µs |
| Gain Bandwidth Product | 28 MHz | 200 kHz |
| Current - Input Bias | 1 pA | 5 pA |
| Voltage - Input Offset | 50 µV | 350 µV |
| Supply Current | 3.7mA (x2 Channels) | 18µA (x2 Channels) |
| Current - Output / Channel | 220 mA | 12 mA |
| Voltage - Supply Span(Min) | 2.7 V | 2.7 V |
| Voltage - Supply Span(Max) | 5.5 V | 18 V |
| Operating Temperature | -40°C ~ 125°C | -40°C ~ 125°C |
| Mounting Type | Surface Mount | Surface Mount |
| -3 dB Bandwidth | - | 305 kHz |
Frequently asked questions
What are the key differences between the AD8657ARMZ-R7 and the AD8656ARMZ?
The AD8657ARMZ-R7 is a dual, low-power, precision CMOS operational amplifier optimized for low supply current (approximately 22 µA per amplifier typical) and rail-to-rail input/output operation, while the AD8656ARMZ is a dual, low-noise, precision CMOS op amp with higher quiescent current (approximately 3.7 mA per amplifier typical) but significantly lower voltage noise density (approximately 2.7 nV/√Hz at 1 kHz). The AD8657 targets battery-powered and portable applications where power consumption is critical, whereas the AD8656 targets applications requiring low noise and higher bandwidth.
Are the AD8657ARMZ-R7 and AD8656ARMZ pin-compatible?
Yes. Both devices are offered in the same 8-lead MSOP (RM) package and share the same standard dual op amp pinout (1=OUT A, 2=-IN A, 3=+IN A, 4=V-, 5=+IN B, 6=-IN B, 7=OUT B, 8=V+). This allows them to be used on the same PCB land pattern, though electrical differences must be evaluated before substitution.
Can the AD8657ARMZ-R7 be used as a direct drop-in replacement for the AD8656ARMZ?
Not unconditionally. Although the packages and pinouts match, the two amplifiers differ in supply current, noise density, gain bandwidth, and slew rate. A direct substitution is only valid after verifying that the lower bandwidth and higher noise of the AD8657ARMZ-R7 meet the target design's requirements, and that the reduced supply current does not affect circuit behavior. Manufacturer datasheets for both parts should be consulted before replacement.
How do the supply current and power consumption of the two devices compare?
The AD8657ARMZ-R7 draws approximately 22 µA per amplifier (typical), making it suitable for low-power and battery-operated designs. The AD8656ARMZ draws approximately 3.7 mA per amplifier (typical), which is substantially higher. Designs prioritizing ultra-low power consumption should favor the AD8657ARMZ-R7, while the AD8656ARMZ is intended for performance-oriented, noise-sensitive applications where higher supply current is acceptable.
How does the voltage noise performance of the AD8657ARMZ-R7 compare with the AD8656ARMZ?
The AD8656ARMZ provides lower voltage noise density, approximately 2.7 nV/√Hz at 1 kHz, making it preferable for low-noise signal conditioning and precision sensor interfaces. The AD8657ARMZ-R7 has higher voltage noise density, consistent with its low-power design. For noise-critical applications, the AD8656ARMZ is the appropriate choice; for power-critical applications, the AD8657ARMZ-R7 is preferred.
What are the gain bandwidth and slew rate specifications for each device?
The AD8656ARMZ offers a gain bandwidth product of approximately 28 MHz and a slew rate of approximately 11 V/µs, supporting higher-frequency signal processing. The AD8657ARMZ-R7 has a lower gain bandwidth product (approximately 230 kHz) and lower slew rate, reflecting its micropower design. Designs requiring wider bandwidth or faster transient response should use the AD8656ARMZ.
Do both devices support rail-to-rail input and output operation?
Yes. Both the AD8657ARMZ-R7 and the AD8656ARMZ are rail-to-rail input and output (RRIO) CMOS operational amplifiers, allowing input and output signal swings close to both supply rails. This makes both parts suitable for single-supply systems with limited headroom, though the specific input/output swing limits and load conditions should be verified in the respective manufacturer datasheets.
What supply voltage ranges are specified for the AD8657ARMZ-R7 and AD8656ARMZ?
Both devices are specified for single-supply operation over a range of approximately 2.7 V to 5.5 V, making them compatible with common 3 V and 5 V systems. Designers should confirm the exact minimum and maximum supply voltages, as well as any dual-supply capability, against the official manufacturer datasheets for each part before finalizing a design.