AD8629ARZ - Zero-Drift Dual Op Amp | Analog Devices
MPN: AD8629ARZ ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $2.38 | $2.38 |
| 10 | $2.14 | $21.40 |
| 100 | $1.92 | $192.00 |
| 500 | $1.72 | $860.00 |
| 1,000 | $1.55 | $1,550.00 |
AD8629ARZ Overview
A zero-drift amplifier is an operational amplifier that continuously corrects its input offset voltage using auto-zeroing or chopping techniques, resulting in microvolt-level offset and near-zero drift over temperature and time. In the amplifier hierarchy, a zero-drift amplifier is a type of precision operational amplifier, which is a subset of linear integrated circuits used for signal conditioning in measurement systems. Engineers select zero-drift amplifiers for sensors, bridges, and data acquisition where DC accuracy is essential.
The AD8629ARZ offers a maximum input offset voltage of 1µV, input offset drift of 0.002µV/°C, and maximum input bias current of 100pA. Its gain, CMRR, and PSRR are all 130dB, providing strong rejection of common-mode and power-supply disturbances. Rail-to-rail input/output swing maximizes dynamic range in single-supply applications, while the dual-channel configuration supports differential or multi-stage designs.
Internally, the AD8629ARZ uses Analog Devices auto-zero topology, which does not require external capacitors and reduces digital switching noise compared with conventional chopper-stabilized amplifiers. The architecture maintains low noise and wide bandwidth while preserving the DC precision of an auto-zero part. The 8-SOIC package is industry standard, straightforward for PCB layout, and compatible with automated assembly.
Typical applications include precision instrumentation, thermocouple and RTD conditioning, medical monitoring, battery-powered portable instruments, IoT sensor nodes, and bridge/strain-gauge signal conditioning. The low offset and drift let systems maintain accuracy for long periods without calibration.
When designing with the AD8629ARZ, place 0.1µF ceramic decoupling capacitors close to the supply pins, avoid driving inputs beyond the rails to prevent latch-up, and use low-value feedback resistors to reduce noise. If a higher supply rail is needed, consider the ADA4522-2ARZ.
Drop-in alternatives for AD8629ARZ — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with AD8629ARZ (same form factor and footprint) — differing in Package, Slew Rate, Gain Bandwidth Product, Number of Channels, Operating Temperature Range.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
AD8629ARZ-REEL7
✅ Drop-In✓ In Stock
$1.48 / Unit
View Datasheet →AD8628ARZ
⚡ Same Package ⚠️ Specs Unverified✓ In Stock
$1.49 / Unit
View Datasheet →ADA4522-2ARZ
⚡ Same Package ⚠️ Specs Unverified✓ In Stock
$3.9 / Unit
View Datasheet →MS8629
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
OP2177ARZ
⚡ Same Package ⚠️ Specs Unverified✓ In Stock
$0.86 / Unit
View Datasheet →AD8629ARZ Maximum Ratings & Electrical Characteristics
| Number of Channels | 2 |
| Supply Voltage Range | 2.7 V to 5 V |
| Input Offset Voltage (max) | 1 µV |
| Input Offset Drift | 0.002 µV/°C |
| Input Bias Current (max) | 100 pA |
| Gain | 130 dB |
| CMRR | 130 dB |
| PSRR | 130 dB |
| Rail-to-Rail Input/Output | Yes |
| Package | 8-SOIC |
| Operating Temperature Range | -40°C to +125°C |
| RoHS Status | Compliant |
| Mounting Type | Surface Mount |
| Amplifier Type | Zero-Drift |
AD8629ARZ Pin Configuration
| Pin 1 | OUT A — Output of amplifier A |
| Pin 2 | -IN A — Inverting input of amplifier A |
| Pin 3 | +IN A — Non-inverting input of amplifier A |
| Pin 4 | V- — Negative supply |
| Pin 5 | +IN B — Non-inverting input of amplifier B |
| Pin 6 | -IN B — Inverting input of amplifier B |
| Pin 7 | OUT B — Output of amplifier B |
| Pin 8 | V+ — Positive supply |
Typical Applications
AD8629ARZ is suitable for 6 applications: Precision Instrumentation, Thermocouple and RTD Conditioning, Medical Monitoring, Battery-Powered Portable Instruments, IoT Sensor Nodes, Bridge and Strain-Gauge Signal Conditioning.
Precision Instrumentation
The AD8629ARZ's 1 µV offset and 0.002 µV/°C drift ensure accurate DC measurements in instrumentation. Its rail-to-rail output maximizes dynamic range, and the dual channel supports differential or multi-stage designs. The low bias current of 100 pA minimizes errors in high-impedance sources, making it ideal for data acquisition systems.
Recommended
Thermocouple and RTD Conditioning
The AD8629ARZ's ultra-low offset and drift are essential for accurate temperature sensing. Its high CMRR of 130 dB rejects common-mode noise in thermocouple leads, while the low bias current prevents self-heating errors in RTDs. The dual channel allows for cold-junction compensation and amplification in a single package.
Recommended
Medical Monitoring
In medical devices, the AD8629ARZ provides the precision needed for ECG, EEG, and blood glucose monitors. Its low offset and drift ensure stable readings over time, and the 2.7V to 5V supply range is compatible with battery-powered equipment. The small 8-SOIC package saves space in portable designs.
Recommended
Battery-Powered Portable Instruments
The AD8629ARZ's low supply voltage (2.7V to 5V) and low power consumption make it ideal for portable instruments. Its rail-to-rail output maximizes battery life by allowing the output to swing close to the supply rails. The dual channel reduces component count, saving board space in compact designs.
Recommended
IoT Sensor Nodes
For IoT sensor nodes, the AD8629ARZ provides accurate signal conditioning with minimal power. Its low offset and drift reduce calibration requirements, and the 2.7V to 5V supply range matches common IoT power rails. The dual channel allows for multiple sensor inputs in a single device, reducing cost and complexity.
Recommended
Bridge and Strain-Gauge Signal Conditioning
The AD8629ARZ's high CMRR (130 dB) and low offset are critical for bridge measurements. Its rail-to-rail output allows full-scale output for small bridge signals, and the low drift ensures accuracy over temperature. The dual channel supports both excitation and amplification in a single package.
Recommended
Recommended Products Summary
Engineering reference data for AD8629ARZ — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | AD8629ARZ-REEL7 | AD8628ARZ | ADA4522-2ARZ | MS8629 |
|---|---|---|---|---|---|
| Package | 8-SOIC | 8-SOIC | 8-SOIC | 8-SOIC | 8-SOIC |
| Brand | Analog Devices | Analog Devices | Analog Devices | Analog Devices | MS |
| Number of Channels | 2 | 2 | 1 | 2 | 2 |
| Supply Voltage Range | 2.7V to 5V | 2.7V to 5V | 2.7V to 5V | 4.5V to 55V | 2.7V to 5.5V |
| Input Offset Voltage (max) | 1 µV | 1 µV | 1 µV | 2.5 µV | 5 µV |
| Input Offset Drift | 0.002 µV/°C | 0.002 µV/°C | 0.002 µV/°C | 0.002 µV/°C | 0.02 µV/°C |
| Input Bias Current (max) | 100 pA | 100 pA | 100 pA | 50 pA | 100 pA |
| CMRR | 130 dB | 130 dB | 130 dB | 140 dB | 120 dB |
Key Differentiators
- Ultra-low offset voltage of 1 µV (vs MS8629)
- Near-zero drift of 0.002 µV/°C (vs MS8629)
- High CMRR of 130 dB (vs MS8629)
Design Notes
Place 0.1µF ceramic decoupling capacitors close to the V+ and V- pins to ensure stable operation. For best performance, use a 10µF tantalum capacitor in parallel for low-frequency decoupling. The AD8629ARZ operates from 2.7V to 5V, so ensure the supply is clean and within this range.
Keep the feedback network components close to the amplifier to minimize parasitic capacitance and inductance. Use a ground plane to reduce noise and provide a low-impedance return path. For high-impedance inputs, guard traces can reduce leakage currents.
Avoid driving inputs beyond the supply rails to prevent latch-up. Use input protection resistors if necessary. Also, ensure the output is not shorted to ground or supply for extended periods, as this can cause thermal stress. For best noise performance, use low-value feedback resistors (e.g., 1kΩ to 10kΩ).
Compliance Information
RoHS compliant per Analog Devices product page. AEC-Q100 not applicable for this commercial-grade part.
