The **AD620BRZ-R7** is a high-accuracy, low-power instrumentation amplifier manufactured by Analog Devices. It is widely considered an industry standard due to its ease of use, requiring only one external resistor to set the gain. --- ### 1. Key Technical Specifications | Parameter | Specification | | :--- | :--- | | **Gain Range** | 1 to 10,000 | | **Gain Equation** | $G = 1 + \frac{49.4\text{ k}\Omega}{R_G}$ | | **Supply Voltage Range** | $\pm2.3\text{ V}$ to $\pm18\text{ V}$ | | **Quiescent Current** | $1.3\text{ mA}$ (Max) | | **Input Offset Voltage** | $50\text{ }\mu\text{V}$ (Max) | | **Input Bias Current** | $1.0\text{ nA}$ (Max) | | **Package Type** | SOIC-8 (Surface Mount) | --- ### 2. Core Functional Blocks The AD620 is based on a modified **three-op-amp architecture**. This design provides several advantages over standard operational amplifiers: 1. **Input Stage:** Uses super-beta transistors to achieve extremely low input bias currents and high input impedance. 2. **Gain Setting ($R_G$):** Unlike discrete designs requiring matched resistor pairs, the AD620 uses a single external resistor across pins 1 and 8 to set the gain. 3. **Output Stage:** Provides a low-impedance output relative to a reference pin (Ref), allowing for easy level shifting. --- ### 3. Pin Configuration (SOIC-8) | Pin # | Name | Description | | :--- | :--- | :--- | | 1, 8 | $R_G$ | Terminals for the gain-setting resistor. | | 2 | $-IN$ | Inverting Input. | | 3 | $+IN$ | Non-inverting Input. | | 4 | $-V_S$ | Negative Supply Power. | | 5 | REF | Reference Pin (sets the "zero" output level). | | 6 | OUTPUT | Signal Output. | | 7 | $+V_S$ | Positive Supply Power. | --- ### 4. Common Applications Due to its high Common-Mode Rejection Ratio (CMRR) and low noise, it is primarily used for amplifying very small differential signals in noisy environments: * **Medical Instrumentation:** ECG and BP monitors. * **Industrial Control:** Precision weigh scales and transducer interfaces. * **Data Acquisition:** Signal conditioning for low-output sensors like thermocouples and strain gauges. --- ### 5. Part Number Breakdown * **AD620**: The base model number. * **B**: Performance Grade (Higher precision/lower offset than "A" grade). * **R**: Package style (SOIC - Small Outline Integrated Circuit). * **Z**: Lead-free/RoHS compliant. * **R7**: Packaging format (7-inch Reel, typically 1,000 units).