AMC23C12 datasheet(12/32 Pages) TI

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7 Detailed Description

7.1 Overview

The AMC23C12 is an isolated window comparator with an open-drain output and optional latch function. The

window comparator is comprised of comparator Cmp0 and Cmp1. Cmp0 compares the input voltage (VIN)

against the positive threshold (VIT+) and Cmp1 compares the input voltage (VIN) against the negative threshold

(VIT–). VIT+ and VIT– are of equal magnitude but opposite signs, therefore the comparison window is centered

around 0 V. The comparison threshold is adjustable from ±20 mV to ±300 mV through an internally generated

100-μA reference current and a single external resistor.

The open-drain output is actively pulled low when the input voltage (VIN) is outside the comparison window.

The behavior when VIN drops back inside the window is determined by the LATCH pin, as described in the

Open-Drain Digital Output section.

When the voltage on the REF pin is greater than VMSEL, the device operates in positive-comparator mode. This

mode is particularly useful for monitoring positive voltages. The negative comparator (Cmp1) is disabled and

only the positive comparator (Cmp0) is functional. The reference voltage in this mode can be as high as 2.7 V.

Galvanic isolation between the high- and low-voltage side of the device is achieved by transmitting the

comparator states across a SiO2-based, reinforced capacitive isolation barrier. This isolation barrier supports

a high level of magnetic field immunity, as described in the ISO72x Digital Isolator Magnetic-Field Immunity

application report. The digital modulation scheme used in the AMC23C12 to transmit data across the isolation

barrier, and the isolation barrier characteristics itself, result in high reliability and common-mode transient

immunity.

7.2 Functional Block Diagram

GND2

OUT

LATCH

VDD2

GND1

REF

VDD1

AMC23C12

–VREF

VREF

Cmp0

Cmp1

LDO

100 μA

AMC23C12

SBASAB2 – FEBRUARY 2022

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AMC23C12 Datasheet(PDF) 12 Page - Texas Instruments