6 Detailed Description

6.1 Overview

The AMC0106M05 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 AMC0106M05 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 filter, such as

a sinc filter at the device output to increase overall performance. This filter also converts 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 AMC0106M05 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.

6.2 Functional Block Diagram

DVDD

DOUT

DGND

AGND

INP

INN

AVDD

CLKIN

Modulator

Diagnostics

Digital

Interface

AMC0106M05

SBASAS7A – AUGUST 2024 – REVISED JUNE 2025

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