**AD8218BRMZ-R7: A High Common-Mode Voltage, Current-Shunt Monitor**

Precision current measurement is a critical requirement in a vast array of industrial, automotive, and telecommunications applications. Systems such as motor controls, power supplies, and battery management systems necessitate accurate monitoring of current flow, often in the presence of high voltages. The **AD8218BRMZ-R7** from Analog Devices stands out as a specialized solution, engineered to excel in these demanding environments as a high-performance **current-shunt monitor**.

This device is fundamentally a difference amplifier, but one that is meticulously optimized for a specific task: amplifying a small voltage developed across a current-sensing shunt resistor, which is situated in a high-voltage line. The core challenge it overcomes is its exceptional ability to reject a very high **common-mode voltage**—up to **65 V**, from a supply voltage as low as 5 V. This means the AD8218 can accurately extract the tiny differential voltage signal (typically tens or hundreds of millivolts) from a power rail that is swinging over a very wide voltage range, rejecting the high common-mode voltage that would overwhelm a standard amplifier.

The AD8218BRMZ-R7 provides a fixed gain of **20 V/V**, translating a differential input signal into a ground-referenced, buffered output voltage that is easy for a downstream analog-to-digital converter (ADC) or microcontroller to digitize. Its architecture ensures a **high common-mode rejection ratio (CMRR)**, which minimizes errors caused by noise on the power bus. Furthermore, its wide operating temperature range (-40°C to +125°C) makes it exceptionally suited for harsh environments, including automotive under-the-hood applications and industrial motor drives.

Key advantages of using the AD8218 include its simplicity of design-in, requiring very few external components, and its ability to enhance system safety by enabling precise overcurrent detection and protection circuits. By providing an accurate representation of load current, it is indispensable for implementing control loops, optimizing power efficiency, and monitoring system health.

**ICGOODFIND**

The AD8218BRMZ-R7 is an indispensable component for engineers designing systems that require robust and precise current monitoring in high-voltage scenarios. Its unparalleled ability to reject high common-mode voltage, combined with its integrated design and reliability, makes it a premier choice for enhancing performance and safety in power-sensitive applications across multiple industries.

**Keywords:**

Current-Shunt Monitor

Common-Mode Voltage

High CMRR

Precision Measurement

Amplifier