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 AD8651ARMZ-R2 is a viable functional replacement candidate for the AD8656ARMZ in many low-noise signal-chain applications, as both share the same MSOP-8 footprint, CMOS rail-to-rail input/output architecture, and wide supply range. However, the AD8656ARMZ offers lower voltage noise and higher output current, so the AD8651ARMZ-R2 should be validated against noise budget and load-driving requirements before adoption.
Package Type
High match
Amplifier Architecture
High match
Voltage Noise Density
Validation required
Output Current Capability
Validation required
Parts at a glance
Part B
AD8651ARMZ-R2
テキサス・インスツルメンツ
- Lifecycle
- Active
- Stock
- 8610 個数
- Package
- TSSOP-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 | AD8656ARMZ | AD8651ARMZ-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 unused-channel handling, and vice versa. |
| Input Offset Voltage (max) | 250 µV | 500 µV | Lower offset improves DC accuracy in precision signal conditioning; a substitution changes the achievable error budget. |
| Input Voltage Noise Density | 2.7 nV/√Hz | 5 nV/√Hz | Noise density directly affects SNR in low-level sensing; the dual part is roughly half the noise, so swapping changes overall noise performance. |
| Gain Bandwidth Product | 28 MHz | 50 MHz | GBW sets the closed-loop bandwidth and stability margin; the single-channel part is faster, which affects achievable signal bandwidth and compensation. |
| Quiescent Current per Amplifier (typ) | 2.3 mA | 3.5 mA | Supply current impacts power budget and thermal design; the dual part draws less per amplifier, changing total system power. |
| Package | 8-Lead MSOP | 8-Lead MSOP | Footprint and pinout must match for board-level drop-in substitution; both share the same package outline but differ in channel configuration. |
| Supply Voltage Range | 2.7 V to 5.5 V | 2.7 V to 5.5 V | Operating supply range must cover the system rail; identical ranges mean both work across the same low-voltage supplies. |
| Rail-to-Rail Input/Output | Yes (RRIO) | Yes (RRIO) | RRIO capability maximizes dynamic range on low supply rails; both share this, so headroom behavior is comparable. |
| Slew Rate | 11 V/µs | 22 V/µs | Slew rate limits large-signal response and settling; the faster single-channel part changes transient performance in the same circuit. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | AD8656ARMZ | AD8651ARMZ-R2 |
|---|---|---|
| Supplier | - | Analog Devices Inc.,Rochester Electronics, LLC |
| Part Status | Active | Obsolete |
| Amplifier Type | CMOS | Voltage Feedback |
| Number of Circuits | 2 | 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 (x2 Channels) | 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 |
| Series | DigiTrim® | - |
Frequently asked questions
What are the key differences between the AD8656ARMZ and AD8651ARMZ-R2?
The AD8656ARMZ is a dual, low-noise, precision CMOS operational amplifier, while the AD8651ARMZ-R2 is a single, low-noise, precision CMOS operational amplifier. Both are offered in an 8-lead MSOP (RM) package, but the AD8656 provides two amplifiers per package whereas the AD8651 provides one amplifier with a different pinout. The AD8651ARMZ-R2 designation indicates a tape-and-reel packaging option.
Are the AD8656ARMZ and AD8651ARMZ-R2 pin-compatible?
No. Although both devices use the same 8-lead MSOP package outline, the AD8656ARMZ is a dual amplifier with both amplifiers' inputs and outputs assigned to the eight pins, while the AD8651ARMZ-R2 is a single amplifier that uses the package pins for one amplifier plus additional pins such as a null or disable function. The pin functions differ, so they are not drop-in replacements for each other.
What are the supply voltage and quiescent current specifications for these amplifiers?
Both the AD8656 and AD8651 are specified for operation from a single supply of 2.7 V to 5.5 V. The AD8656 (dual) typically draws approximately 2.3 mA per amplifier quiescent current, while the AD8651 (single) typically draws approximately 2.3 mA total. These low quiescent currents suit battery-powered and portable instrumentation applications.
What noise and bandwidth performance do the AD8656ARMZ and AD8651ARMZ-R2 offer?
Both devices feature a low input voltage noise density of approximately 2.7 nV/√Hz at 1 kHz and a gain bandwidth product of approximately 28 MHz. These characteristics make them suitable for low-noise signal conditioning, precision filtering, and audio or sensor interface applications requiring wide bandwidth and low distortion.
Can the AD8651ARMZ-R2 be used as a replacement for one channel of the AD8656ARMZ?
Functionally, a single AD8651 amplifier channel is comparable to one channel of the AD8656 dual amplifier in terms of noise, bandwidth, and supply range. However, because the pinouts differ, a board designed for the dual AD8656ARMZ cannot directly accept the single AD8651ARMZ-R2 without layout changes. Replacement requires verifying pin functions and PCB land patterns against the respective datasheets.
What input offset voltage and temperature drift do these amplifiers specify?
The AD8656 and AD8651 are precision CMOS amplifiers with a typical input offset voltage of approximately 50 µV and a maximum offset voltage on the order of a few hundred microvolts, depending on grade. Offset voltage drift is typically around 0.4 µV/°C. These low offset and drift values support high-accuracy DC signal conditioning.
What are the operating temperature ranges and packaging options for the AD8656ARMZ and AD8651ARMZ-R2?
Both devices are specified over the industrial temperature range of −40 °C to +125 °C. The AD8656ARMZ is supplied in an 8-lead MSOP tube or reel packaging, and the AD8651ARMZ-R2 is supplied in an 8-lead MSOP tape-and-reel format (the R2 suffix denotes the reel quantity option). Designers should confirm the exact packaging quantity and ordering code against the manufacturer's ordering guide.