## Technical Overview of the AD8221BRZ-R7 The **AD8221BRZ-R7** is a high-performance, precision instrumentation amplifier manufactured by **Analog Devices**. It is widely recognized for its industry-leading Common-Mode Rejection Ratio (CMRR) and its ability to maintain high performance over a wide frequency range. --- ### 1. Key Technical Specifications | Feature | Specification | | :--- | :--- | | **Type** | Precision Instrumentation Amplifier | | **Gain Range** | 1 to 1000 (Set by a single resistor) | | **CMRR (min)** | 80 dB (G=1) to 110 dB (G=1000) @ 60Hz | | **Input Offset Voltage** | 60 µV (Maximum) | | **Gain Drift** | 10 ppm/°C (Maximum) | | **Bandwidth (-3dB)** | 825 kHz (G=1) | | **Supply Voltage Range** | ±2.3 V to ±18 V | | **Package / Case** | SOIC-8 (N-Suffix) | --- ### 2. Functional Characteristics The AD8221 is designed to extract small differential signals in the presence of large common-mode noise. * **High CMRR over Frequency:** Unlike standard instrumentation amplifiers, the AD8221 maintains a high CMRR even at higher frequencies (up to 10 kHz), making it ideal for rejecting line noise and harmonics. * **Low Noise:** It features a low input voltage noise of **8 nV/√Hz** at 1 kHz, which is essential for precision sensor measurements. * **Gain Equation:** The gain is programmed using a single external resistor ($R_G$) according to the formula: `G = 1 + (49.4 kΩ / RG)` --- ### 3. Pin Configuration (SOIC-8) | Pin Number | Name | Function | | :--- | :--- | :--- | | 1 | -IN | Inverting Input | | 2 | RG | Gain Setting Resistor Pin | | 3 | RG | Gain Setting Resistor Pin | | 4 | +IN | Non-inverting Input | | 5 | -Vs | Negative Supply Voltage | | 6 | REF | Reference Pin (sets output ground level) | | 7 | Vout | Output Voltage | | 8 | +Vs | Positive Supply Voltage | --- ### 4. Typical Applications * **Medical Instrumentation:** ECG and EEG monitoring where small signals are buried in noise. * **Industrial Process Control:** Bridge amplifiers for pressure and temperature sensors. * **Data Acquisition:** High-precision analog-to-digital converter (ADC) drivers. * **Precision Weight Scales:** Strain gauge amplification. --- ### 5. Part Number Breakdown (AD8221BRZ-R7) * **AD8221:** Base Model Number. * **B:** Grade (Indicates higher precision/performance tier than 'A' grade). * **R:** Package type (SOIC). * **Z:** Lead-free/RoHS compliant. * **R7:** Packaging format (7-inch Tape and Reel, typically 1,000 units).