6 Detailed Description

6.1 Overview

The AMC0100R is a precision, galvanically isolated amplifier with a ±250mV differential input, and single-ended,

ratiometric output. The input stage of the device drives a second-order, delta-sigma (ΔΣ) modulator. The

modulator converts the analog input signal into a digital bitstream that is transferred across the isolation barrier

that separates the high-side from the low-side.

On the low-side, the received bitstream is processed by an analog filter that outputs a GND2-referenced,

single-ended signal at the OUT pin. This single-ended output signal is proportional to the input signal. The

full-scale output voltage of the isolated amplifier is equal to the voltage applied to the REFIN pin.

The SiO2-based, capacitive isolation barrier supports a high level of magnetic field immunity, as described in the

ISO72x Digital Isolator Magnetic-Field Immunity application note. The digital modulation used in the AMC0100R

transmits data across the isolation barrier. This modulation, and the isolation barrier characteristics, result in high

reliability and high common-mode transient immunity.

6.2 Functional Block Diagram

ΔΣ Modulator

GND1

INP

INN

VDD1

Reference

20 MHz Oscillator

VDD2

OUT

REFIN

GND2

Analog Filter

1.44V

+

–

216kΩ

96kΩ

DAC

6.3 Feature Description

6.3.1 Analog Input

The high-impedance input buffer on the INP pin feeds a second-order, switched-capacitor, feed-forward ΔΣ

modulator. The modulator converts the analog signal into a bitstream that is transferred across the isolation

barrier, as described in the Isolation Channel Signal Transmission section.

There are two restrictions on the analog input signal. First, if the input voltage exceeds the value specified in

the Section 5.1 table, the input current must be limited to 10mA. This limitation is caused by the device input

electrostatic discharge (ESD) diodes turning on. Second, linearity and noise performance are specified only

when the input voltage is within the linear full-scale range (VFSR). VFSR is specified in the Section 5.3 table.

AMC0100R

SBASAS5 – OCTOBER 2025

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