The **AD629ARZ-R7** is a high-performance, high common-mode voltage difference amplifier manufactured by Analog Devices. It is specifically designed to measure small differential signals in the presence of very high common-mode voltages. --- ### ## Technical Specifications The following table highlights the core electrical characteristics of the AD629ARZ-R7: | Feature | Specification | | :--- | :--- | | **Common-Mode Voltage Range** | ±270 V (Continuous) | | **Supply Voltage Range** | ±2.5 V to ±18 V | | **Gain (Fixed)** | 1 V/V | | **CMRR (Common-Mode Rejection)** | 86 dB (minimum, DC to 500 Hz) | | **Bandwidth (-3 dB)** | 500 kHz | | **Slew Rate** | 2.1 V/µs | | **Package Type** | 8-Lead SOIC_N (R-7 Reel) | | **Operating Temperature** | -40°C to +85°C | --- ### ## Internal Architecture & Pin Configuration The device uses a specialized internal resistor network to attenuate high voltages before they reach the internal op-amp, allowing it to handle signals far beyond its supply rails. | Pin Number | Pin Name | Description | | :--- | :--- | :--- | | 1 | NC | No internal connection | | 2 | -IN | Inverting Input | | 3 | +IN | Non-inverting Input | | 4 | -Vs | Negative Supply Voltage | | 5 | REF(-) | Reference Input (Negative) | | 6 | OUT | Output | | 7 | +Vs | Positive Supply Voltage | | 8 | REF(+) | Reference Input (Positive) | --- ### ## Key Features * **High Common-Mode Rejection:** It can extract a small differential signal even when riding on a ±270V common-mode voltage, which would destroy standard operational amplifiers. * **Integrated Resistors:** The internal thin-film resistors are laser-trimmed to ensure excellent gain accuracy and high CMRR over temperature. * **Versatility:** The dual reference pins allow for easy offsetting of the output signal, which is useful for interfacing with single-supply ADCs. ### ## Typical Applications 1. **High Voltage Current Sensing:** Monitoring current on high-voltage power rails using a shunt resistor. 2. **Battery Stack Monitoring:** Measuring individual cell voltages in large series-connected battery packs (EVs, Solar storage). 3. **Motor Control:** Sensing phase currents in industrial motor drives. 4. **Isolation Replacement:** In some scenarios, it can replace expensive isolation amplifiers if galvanic isolation is not strictly required. --- ### ## Design Tip (Code/Formula) When calculating the output voltage ($V_{out}$), the transfer function is: ```text Vout = (V+in - V-in) + Vref ``` *Where $V_{ref}$ is the voltage applied to the reference pins, allowing you to level-shift the output for bipolar signals.*