The AMC0106M25 is a single-channel, second-order, CMOS, delta-sigma (ΔΣ) modulator designed for high-resolution analog-to-digital conversions of AC signals. The differential analog input of the AMC0106M25 is implemented with a switched-capacitor circuit. The isolated output of the converter (DOUT) provides a stream of digital ones and zeros synchronous to the external clock applied to the CLKIN pin. The time average of this serial output is proportional to the analog input voltage.

The modulator shifts the quantization noise to high frequencies. Therefore, use a digital low-pass digital filter, such as a sinc filter at the device output to increase overall performance. This filter also converts from the 1-bit data stream at a high sampling rate into a higher-bit data word at a lower rate (decimation). Use a microcontroller (μC) or field-programmable gate array (FPGA) to implement the filter.

The overall performance (speed and resolution) depends on the selection of an appropriate oversampling ratio (OSR) and filter type. A higher OSR results in higher resolution while operating at a lower refresh rate. A lower OSR results in lower resolution, but provides data at a higher refresh rate. Multiple filters can run in parallel. For example, a low OSR filter for fast overcurrent detection and a high OSR filter for high resolution current measurement.

The silicon-dioxide (SiO₂) based capacitive isolation barrier supports a high level of magnetic field immunity; see the ISO72x Digital Isolator Magnetic-Field Immunity application note. The AMC0106M25 uses an on-off keying (OOK) modulation scheme to transmit data across the isolation barrier. This modulation, and the isolation barrier characteristics, result in high reliability in noisy environments and high common-mode transient immunity.