The **AD8223ARMZ-R7** is an integrated, low-cost, single-supply instrumentation amplifier manufactured by **Analog Devices**. It is designed to amplify small differential signals in the presence of common-mode noise, making it ideal for sensor interfacing. --- ### 1. Key Technical Specifications | Feature | Specification | | :--- | :--- | | **Architecture** | 3-Op Amp Instrumentation Amplifier | | **Package** | 8-Lead MSOP (ARMZ suffix) | | **Supply Voltage** | 2.7 V to 36 V (Single) or ±1.35 V to ±18 V (Dual) | | **Gain Range** | 5 to 1000 (Set by a single external resistor) | | **Quiescent Current** | 600 µA (Max) | | **Input Bias Current** | 20 nA (Max) | | **CMRR** | 80 dB (G=5) to 110 dB (G=1000) | | **Bandwidth** | 200 kHz (G=5) | --- ### 2. Functional Description The AD8223 is a "Rail-to-Rail" output amplifier, meaning the output signal can swing very close to the positive and negative supply rails. #### A. Gain Setting The gain ($G$) is determined by an external resistor ($R_G$) connected between pins 1 and 8. If no resistor is used, the default gain is **5**. The formula for calculating the required resistor is: $$R_G = \frac{100 \text{ k}\Omega}{G - 5}$$ #### B. Single Supply Operation Unlike traditional instrumentation amplifiers that require dual power supplies (e.g., ±15V), the AD8223 is optimized for modern single-supply systems (e.g., +5V or +3.3V). Its input common-mode range includes ground, allowing it to sense signals near 0V. #### C. Robustness The device includes internal ESD protection and can handle input voltages beyond the supply rails (up to 25V beyond the opposite rail in some configurations), providing durability in industrial environments. --- ### 3. Pin Configuration | Pin | Mnemonic | Description | | :--- | :--- | :--- | | 1, 8 | $R_G$ | Gain setting terminals | | 2 | -IN | Inverting Input | | 3 | +IN | Non-inverting Input | | 4 | -V_S | Negative Supply (or Ground) | | 5 | REF | Reference (Sets the output zero level) | | 6 | VOUT | Output | | 7 | +V_S | Positive Supply | --- ### 4. Common Applications * **Medical Instrumentation:** ECG and BP monitors. * **Industrial Process Control:** Transducer interfaces (pressure, temperature). * **Portable Systems:** Battery-powered weigh scales and handheld sensors. * **Current Sensing:** Shunt resistor amplification.