The **AD628ARMZ-R7** is a high-performance, precision differential amplifier designed by Analog Devices. It is specifically engineered to handle high common-mode voltages while extracting small differential signals, making it ideal for industrial and automotive applications. --- ### 1. Key Technical Specifications | Parameter | Specification | | :--- | :--- | | **Type** | Difference Amplifier | | **Common-Mode Voltage Range** | ±120V (at Vs = ±15V) | | **Supply Voltage (Single)** | 4.5V to 36V | | **Supply Voltage (Dual)** | ±2.25V to ±18V | | **Gain Range** | 0.1 to 100 (Externally Configurable) | | **Bandwidth** | 600 kHz | | **CMRR (Min)** | 75 dB (DC to 500 Hz) | | **Package Type** | 8-MSOP (Micro Small Outline Package) | --- ### 2. Core Functional Parts The AD628 consists of several internal sections that allow it to function as a versatile signal conditioner: #### A. High-Voltage Input Scaling The device uses an internal resistor network that scales down high input voltages. This allows the amplifier to process signals with a common-mode voltage of up to **±120V**, even when the chip itself is powered by a much lower supply (e.g., 5V). #### B. Internal Precision Resistors The resistors are laser-trimmed to ensure high matching. This precision is what provides the high **Common-Mode Rejection Ratio (CMRR)**, allowing the chip to ignore high-voltage "noise" and focus on the tiny difference between inputs. #### C. Buffering and Filtering * **VREF Pin:** Allows for level shifting. You can apply a voltage here to bias the output to a specific level (e.g., 2.5V for a 0-5V ADC). * **Filter Pin:** Provides access to the internal nodes to allow the user to add an external capacitor, creating a low-pass filter to reduce high-frequency noise. --- ### 3. Applications and Use Cases Due to its high voltage tolerance and precision, the AD628 is commonly used in: 1. **Current Sensing:** Measuring the voltage drop across a shunt resistor in high-voltage power lines. 2. **Motor Control:** Monitoring phase currents in industrial motors. 3. **Battery Management Systems (BMS):** Measuring individual cell voltages in high-voltage battery stacks. 4. **Isolation Interface:** Acting as a bridge between high-voltage sensors and low-voltage microcontrollers/ADCs. --- ### 4. Ordering Information (Decoding the Suffix) * **AD628**: The base model number. * **ARMZ**: Indicates the 8-lead MSOP package and RoHS compliance (lead-free). * **R7**: Indicates the packaging format (7-inch Tape and Reel, typically 1,000 pieces).