## Overview of the AD8628ARTZ-R2 The **AD8628ARTZ-R2** is a high-precision, ultra-low offset voltage operational amplifier manufactured by **Analog Devices**. It belongs to the "Zero-Drift" family, utilizing chopper-stabilized technology to provide near-zero DC offset and drift over temperature and time. ### Key Specifications | Parameter | Specification | | :--- | :--- | | **Architecture** | Zero-Drift (Chopper Stabilized) | | **Offset Voltage ($V_{OS}$)** | 1 $\mu$V (Typical), 5 $\mu$V (Maximum) | | **Offset Drift** | 0.005 $\mu$V/°C | | **Operating Voltage Range** | 2.7 V to 5.0 V | | **Gain Bandwidth Product** | 2.5 MHz | | **Input Bias Current** | 30 pA | | **Package Type** | SOT-23-5 | | **Temperature Range** | -40°C to +125°C | --- ### Core Electronic Features #### 1. Zero-Drift Technology The most significant feature of the AD8628 is its ability to eliminate $1/f$ noise (flicker noise). By continuously sampling and correcting the input offset, the device maintains extreme accuracy even in environments with fluctuating temperatures. #### 2. Rail-to-Rail Input and Output (RRIO) * **Input:** The common-mode input range includes both the negative and positive supply rails. * **Output:** The output can swing within millivolts of the supply rails, maximizing the dynamic range for low-voltage ADCs. #### 3. Low Noise and High Speed Despite being a zero-drift amplifier, it offers a 2.5 MHz bandwidth and a low noise density (approx. 22 nV/√Hz), making it suitable for AC signals as well as precision DC measurements. --- ### Pin Configuration (SOT-23-5) | Pin Number | Mnemonic | Description | | :--- | :--- | :--- | | 1 | OUT | Amplifier Output | | 2 | V- | Negative Supply (or Ground) | | 3 | +IN | Non-inverting Input | | 4 | -IN | Inverting Input | | 5 | V+ | Positive Supply | --- ### Typical Applications 1. **Precision Weigh Scales:** Used to amplify minute signals from load cells. 2. **Current Sensing:** Ideal for shunt-based current monitoring due to the ultra-low offset. 3. **Medical Instrumentation:** High-accuracy ECG/EEG amplification where DC precision is critical. 4. **Thermocouple Amplifiers:** Measuring microvolt-level changes in temperature sensors. --- ### Part Number Breakdown: AD8628ARTZ-R2 * **AD8628:** The base model number (Single version). * **A:** Performance grade (Standard). * **RT:** Package designator for SOT-23. * **Z:** RoHS compliant (Lead-free). * **R2:** Packaging suffix (7-inch reel containing 250 units).