Part A
AD8629ARMZ
Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 3786 Stückzahl
- Package
- TSSOP-8
- Series
- Linear-Verstärker.Instrumentation, OP-Verstärker, Pufferverstärker
Replacement verdict
Compatible functional replacement candidate
The AD8629ARMZ and AD8625ARU are both dual, precision, low-power operational amplifiers from Analog Devices, making the AD8629ARMZ a viable functional replacement candidate for the AD8625ARU in many designs. However, the two parts differ in package footprint, supply voltage range, and input bias current characteristics, so the substitution should be validated against the target application's supply rails, board layout, and input impedance requirements before adoption.
Amplifier Channel Count
High match
Package Type
Validation required
Supply Voltage Range
Validation required
Input Bias Current
Validation required
Parts at a glance
Part B
AD8625ARU
Analog Devices Inc.
- Lifecycle
- Active
- Stock
- 4013 Stückzahl
- Package
- TSSOP-14
- 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 | AD8629ARMZ | AD8625ARU | Why it matters |
|---|---|---|---|
| Number of Amplifiers | 2 (Dual) | 4 (Quad) | Channel count determines how many independent signal paths can be processed in one package; a dual cannot directly replace a quad in multi-channel designs. |
| Input Offset Voltage (Max) | 5 µV | 500 µV | Lower offset voltage improves DC precision; the AD8629 is a zero-drift amplifier with far tighter offset, affecting accuracy in precision sensor interfaces. |
| Input Offset Voltage Drift (Typ) | 0.005 µV/°C | 1.5 µV/°C | Drift determines offset stability over temperature; the AD8629's chopper stabilization gives dramatically better temperature stability. |
| Gain Bandwidth Product | 2.5 MHz | 5 MHz | GBW sets the achievable closed-loop bandwidth and settling behavior; the AD8625 offers roughly twice the bandwidth for faster signal processing. |
| Input Noise Voltage Density (Typ) | 22 nV/√Hz | 16 nV/√Hz | Lower voltage noise improves SNR in low-level signal amplification; the AD8625 has somewhat lower noise density. |
| Supply Current per Amplifier (Typ) | 1.0 mA | 0.8 mA | Quiescent current affects power budget; per-amplifier consumption differs and total package current depends on channel count. |
| Supply Voltage Range | 2.7 V to 5 V (single) / ±1.35 V to ±2.5 V (dual) | 5 V to 26 V (single) / ±2.5 V to ±13 V (dual) | Operating voltage range must match the system rail; the AD8625 supports much higher supply voltages, while the AD8629 is limited to low-voltage rails. |
| Package Type | 8-Lead MSOP | 14-Lead TSSOP | Footprint and pinout compatibility are essential for board-level substitution; different packages require layout changes. |
| Operating Temperature Range | -40 °C to +125 °C | -40 °C to +85 °C | The temperature range defines environmental limits; the AD8629 supports extended-temperature applications the AD8625 does not. |
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Full specification comparison
Use manufacturer datasheets as the final authority.
| Specification | AD8629ARMZ | AD8625ARU |
|---|---|---|
| Supplier | - | Rochester Electronics, LLC |
| Part Status | Active | Obsolete |
| Amplifier Type | Zero-Drift | J-FET |
| Number of Circuits | 2 | 4 |
| Output Type | Rail-to-Rail | Rail-to-Rail |
| Slew Rate | 1V/µs | 5V/µs |
| Gain Bandwidth Product | 2.5 MHz | 5 MHz |
| Current - Input Bias | 30 pA | 0.25 pA |
| Voltage - Input Offset | 1 µV | 350 µV |
| Supply Current | - | 710µA (x4 Channels) |
| Current - Output / Channel | 30 mA | 15 mA |
| Voltage - Supply Span(Min) | 2.7 V | 5 V |
| Voltage - Supply Span(Max) | 5 V | 26 V |
| Operating Temperature | -40°C ~ 125°C | -40°C ~ 85°C |
| Mounting Type | Surface Mount | Surface Mount |
| -3 dB Bandwidth | 2.5 MHz | - |
Frequently asked questions
What are the primary differences between the AD8629ARMZ and the AD8625ARU?
The AD8629ARMZ is a dual, zero-drift, rail-to-rail operational amplifier supplied in an 8-lead MSOP (RMZ) package. The AD8625ARU is a quad, low-power, rail-to-rail JFET-input operational amplifier supplied in a 14-lead TSSOP (RU) package. The most significant differences are channel count (dual vs. quad), input stage topology (zero-drift CMOS vs. JFET), and package footprint.
Are the AD8629ARMZ and AD8625ARU pin-compatible?
No. The AD8629ARMZ uses an 8-lead MSOP pinout for a dual amplifier, while the AD8625ARU uses a 14-lead TSSOP pinout for a quad amplifier. The pin counts, pin functions, and package dimensions differ, so they are not drop-in replacements for one another.
How do the input bias currents of the AD8629ARMZ and AD8625ARU compare?
The AD8629ARMZ, with its zero-drift CMOS input stage, specifies very low input bias current (typically in the picoampere range). The AD8625ARU, using a JFET input stage, specifies input bias current in the low picoampere range as well, but the exact values differ between the two datasheets. Designers should consult the respective Analog Devices datasheets for the guaranteed limits over temperature.
Which device is better suited for very low offset voltage precision applications?
The AD8629ARMZ is specifically designed as a zero-drift amplifier with very low offset voltage and offset voltage drift, making it well suited for precision DC applications. The AD8625ARU is a low-power JFET-input amplifier with good offset performance but is not specified as a zero-drift device. For the lowest offset and drift, the AD8629ARMZ is the more appropriate choice.
Do both the AD8629ARMZ and AD8625ARU support rail-to-rail input and output operation?
Yes. Both the AD8629ARMZ and the AD8625ARU are specified with rail-to-rail input and output swing, allowing them to operate with signal levels close to both supply rails. This makes both devices suitable for single-supply signal conditioning where maximum dynamic range is required.
How do the supply voltage ranges of the AD8629ARMZ and AD8625ARU compare?
Both devices operate from single-supply or dual-supply configurations. The AD8629ARMZ is specified for operation from 2.7 V to 5 V single supply (or ±1.35 V to ±2.5 V dual supply). The AD8625ARU is specified for operation from 5 V to 26 V single supply (or ±2.5 V to ±13 V dual supply). The AD8625ARU therefore supports higher supply voltages, while the AD8629ARMZ targets lower-voltage systems.
Which device consumes less quiescent current per amplifier?
Both are low-power devices, but their quiescent current specifications differ. The AD8629ARMZ typically draws approximately 1 mA per amplifier, while the AD8625ARU is specified with a lower supply current per amplifier. For exact quiescent current values and test conditions, refer to the official Analog Devices datasheets for each part.
Can the AD8629ARMZ and AD8625ARU be used interchangeably in an existing PCB design?
No. Because the two devices differ in package type (8-lead MSOP vs. 14-lead TSSOP), channel count (dual vs. quad), input stage topology, and supply voltage range, they cannot be used interchangeably without a PCB redesign and full revalidation of the circuit against the target device's datasheet.