Isolation Amplifiers

AMC0302D

AMC0302D - ±50mV Reinforced Isolated Amplifier | Texas Instruments

The AMC0302D from Texas Instruments is a precision, ±50mV-input reinforced isolated amplifier with a differential output. It is designed for accurate current sensing in motor drives, inverters, and other power electronics where galvanic isolation is required. The device provides a fixed gain of 8.2 V/V and operates from a single 3.3V or 5V supply on the high-side, with a separate 3.3V or 5V supply on the low-side. The reinforced isolation barrier is certified to withstand 5kVRMS (DWV package) or 3kVRMS (D package) for 60 seconds, ensuring safety in high-voltage applications. An isolated amplifier is a type of amplifier that provides electrical isolation between its input and output stages, allowing signal measurement across a potential difference while protecting low-voltage circuitry from high-voltage transients. It is a key component in the signal chain of power conversion systems, bridging the gap between high-voltage power stages and low-voltage control electronics. The AMC0302D belongs to the family of isolation amplifiers, which are essential for current sensing, voltage sensing, and isolated data acquisition. Key features of the AMC0302D include a linear input voltage range of ±50mV, a fixed gain of 8.2 V/V, and a bandwidth of 250 kHz. The device offers excellent DC accuracy with a maximum offset error of ±0.3mV and a gain error of ±0.2%. It also features a low temperature drift of ±5 µV/°C, ensuring stable performance over the full -40°C to +125°C temperature range. The differential output is insensitive to ground shifts, enabling reliable signal transmission over long distances. The AMC0302D uses a sigma-delta modulation architecture with an internal reference, providing high-resolution conversion of the input signal. The isolation barrier is implemented using capacitive coupling, which offers high immunity to magnetic interference and supports high-speed data transmission. The device is available in both wide-body (DWV) and narrow-body (D) SOIC-8 packages, with the DWV package providing reinforced isolation up to 5kVRMS. Typical applications include motor phase current sensing in variable frequency drives, inverter current monitoring in solar and UPS systems, and isolated current sensing in industrial automation. The AMC0302D is also suitable for battery management systems and power monitoring in electric vehicles. Its high accuracy and isolation rating make it ideal for safety-critical applications. When designing with the AMC0302D, ensure proper PCB layout to maintain isolation creepage and clearance distances. Place the high-side and low-side ground planes separately and avoid routing high-voltage traces under the device. Use appropriate filtering on the input to reduce noise and ensure stable operation.