Part A
AD8651ARMZ
Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 6670 Stückzahl
- Package
- MSOP-8
- Series
- Linear-Verstärker.Instrumentation, OP-Verstärker, Pufferverstärker
Replacement verdict
Compatible functional replacement candidate
The AD8657ARMZ and AD8651ARMZ share the same MSOP-8 package, dual op-amp configuration, and 2.7 V to 5.5 V supply range, making them functionally interchangeable in many designs. However, the AD8657ARMZ offers lower quiescent current and wider operating temperature range, while the AD8651ARMZ provides higher bandwidth and faster slew rate. Designers should validate AC performance and thermal margins before substituting in noise-sensitive or high-speed signal chains.
Package Type
High match
Channel Count
High match
Supply Voltage Range
Validation required
Gain Bandwidth Product
Not compatible
Parts at a glance
Part B
AD8657ARMZ
Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 2097 Stückzahl
- Package
- MSOP-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 | AD8657ARMZ | AD8651ARMZ | 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 without layout changes. |
| Supply Voltage Range | 2.7 V to 5.5 V | 2.7 V to 5.5 V | Both operate over the same low-voltage range, so power-supply compatibility is maintained across the substitution. |
| Input Offset Voltage (Max) | 350 µV | 500 µV | Lower offset improves DC accuracy; the dual part offers tighter offset, which can affect precision in sensor and instrumentation front ends. |
| Gain Bandwidth Product | 2.5 MHz | 50 MHz | GBW sets the achievable closed-loop bandwidth; the single AD8651 is far faster, so it suits high-speed signal paths the AD8657 cannot match. |
| Slew Rate | 1.2 V/µs | 30 V/µs | Slew rate limits large-signal response; the much higher slew rate of the AD8651 matters for fast transients and high-frequency waveforms. |
| Input Bias Current (Typ) | 1 pA | 10 pA | Very low bias current minimizes errors in high-impedance sources; both are CMOS-grade, but the AD8657 is slightly better for ultra-high-impedance nodes. |
| Supply Current per Amplifier (Typ) | 220 µA | 8 mA | Quiescent current drives power budget; the AD8657 is a micropower part while the AD8651 draws far more, critical for battery-powered designs. |
| Input Voltage Noise Density | 22 nV/√Hz | 5 nV/√Hz | Lower noise density improves SNR in low-level signal amplification; the AD8651 is significantly quieter for precision analog front ends. |
| Package | 8-Lead MSOP | 8-Lead MSOP | Identical package footprint allows drop-in board placement, though pin functions differ between single and dual configurations. |
| Operating Temperature Range | -40 °C to +125 °C | -40 °C to +125 °C | Matching industrial temperature ratings ensure both parts meet the same environmental requirements for harsh-environment applications. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | AD8651ARMZ | AD8657ARMZ |
|---|---|---|
| Series | DigiTrim® | - |
| Part Status | Active | Active |
| Amplifier Type | Voltage Feedback | CMOS |
| Number of Circuits | 1 | 2 |
| Output Type | Rail-to-Rail | Rail-to-Rail |
| Slew Rate | 41V/µs | 0.08V/µs |
| Gain Bandwidth Product | 50 MHz | 200 kHz |
| Current - Input Bias | 1 pA | 5 pA |
| Voltage - Input Offset | 100 µV | 350 µV |
| Supply Current | 9.5mA | 18µA (x2 Channels) |
| Current - Output / Channel | 40 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 and AD8651ARMZ operational amplifiers?
The AD8657ARMZ is a dual, low-power, precision CMOS op amp optimized for low supply current (approximately 22 µA per amplifier) and rail-to-rail input/output operation, making it suited for battery-powered and portable applications. The AD8651ARMZ is a single, high-speed CMOS op amp with a 50 MHz gain-bandwidth product and fast slew rate, intended for higher-bandwidth signal processing. They differ in channel count, supply current, bandwidth, and target application profile.
Are the AD8657ARMZ and AD8651ARMZ pin-compatible?
No. The AD8657ARMZ is a dual op amp in an 8-lead MSOP package, while the AD8651ARMZ is a single op amp in an 8-lead MSOP package. Although both use the same package outline, their pin functions and internal channel configurations differ, so they are not direct drop-in replacements for each other.
What are the supply voltage ranges for the AD8657ARMZ and AD8651ARMZ?
Both devices operate from a single supply of 2.7 V to 5.5 V. The AD8657ARMZ is specified for low-voltage, low-power operation with rail-to-rail input and output, while the AD8651ARMZ is specified for high-speed operation over the same supply range.
How do the bandwidth and slew rate of the AD8657ARMZ and AD8651ARMZ compare?
The AD8651ARMZ offers a 50 MHz gain-bandwidth product and a slew rate of approximately 22 V/µs, suitable for high-speed signal chains. The AD8657ARMZ has a much lower gain-bandwidth product (on the order of tens to hundreds of kHz) and lower slew rate, reflecting its design emphasis on low power consumption rather than speed.
Which device is better suited for battery-powered portable applications?
The AD8657ARMZ is generally better suited for battery-powered portable applications because of its very low supply current (approximately 22 µA per amplifier) and rail-to-rail input/output swing, which maximizes dynamic range at low supply voltages. The AD8651ARMZ draws significantly higher supply current to support its high-speed operation.
Can the AD8657ARMZ and AD8651ARMZ be used interchangeably in an existing design?
No. Because they differ in channel count (dual vs. single), pin configuration, supply current, bandwidth, and slew rate, they cannot be used interchangeably without redesigning the circuit and validating performance against the manufacturer datasheets for each device.
What package options are available for the AD8657ARMZ and AD8651ARMZ?
Both the AD8657ARMZ and AD8651ARMZ are offered in an 8-lead MSOP (Mini Small Outline Package) with the "RMZ" suffix indicating the MSOP package and RoHS-compliant construction. Designers should confirm exact package and ordering codes against the official Analog Devices datasheets.