Isolation

Barrier

CLKIN

DOUT

HLDO_OUT

AMC3306

RX

GND

INP

INN

Diagnostic

û Modulator

VDD

DCDC_OUT

Resonator

and

Driver

LDO

Rectifier

TX

HGND

LDO_OUT

DCDC_IN

DCDC_GND

TX

RX

Diagnostics

Bandgap

Reference

LDO

DCDC_HGND

HLDO_IN

Interface

DIAG

12

AMC3306M25

SBAS996 – MAY 2020

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7 Detailed Description

7.1 Overview

The AMC3306M25 is a fully-differential, precision, isolated amplifier with an integrated DC/DC converter that

allows the device to be supplied from a single 3.3-V or 5-V voltage supply source on the low side. The analog

input pins INP and INN are connected to a fully differential amplifier feeding the switched-capacitor input of a

second-order, delta-sigma (ΔΣ) modulator stage that digitizes the input signal into a 1-bit output stream. The

isolated data output, DOUT, of the modulator provides a stream of digital ones and zeros that is synchronous to

the externally provided clock source at the CLKIN pin with a frequency in the range of 5 MHz to 21 MHz. The

time average of this serial bitstream output is proportional to the analog input voltage.

The Functional Block Diagram section shows a detailed block diagram of the AMC3306M25. The analog input

range is tailored to directly accommodate a voltage drop across a shunt resistor used for current sensing. The

external clock input simplifies the synchronization of multiple current-sensing, or current and voltage-sensing

channels on the system level.

described in the ISO72x Digital Isolator Magnetic-Field Immunity application report, available for download at

www.ti.com.

7.2 Functional Block Diagram