VDD2

VDD1

ISO224

5 V

AC

Voltage

Source

GND1

GND1

GND2

5 V

ADC

GND2

15

ISO224

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SBAS738 – JUNE 2018

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9 Application and Implementation

NOTE

Information in the following applications sections is not part of the TI component

specification, and TI does not warrant its accuracy or completeness. TI’s customers are

responsible for determining suitability of components for their purposes. Customers should

validate and test their design implementation to confirm system functionality.

9.1 Application Information

The ISO224 enables high-precision measurement of ±10-V signals that are used in a harsh environment in a

wide range of industrial applications. The high input resistance of the device simplifies the connection of its input

to different sensors or other signal sources. The very low nonlinearity, ac and dc errors, and temperature drift

make the ISO224 a robust, high-performance, isolated amplifier for applications where high voltage isolation is

required. The differential 4-V output offers high immunity to noise and allows connection to a wide range of

analog-to-digital converters (ADCs) powered on a 5-V nominal supply.

9.2 Typical Application

Isolated amplifiers are often used for data acquisition in industrial applications to safely separate the low-voltage

portion of the system from the high common-mode voltage input of the system. The input structure of the ISO224

is optimized for isolated voltage sensing in this kind of application.

Figure 9 shows a typical operation of the device for voltage sensing as used in power line monitoring systems.

The phase voltage amplitude is reduced with a resistive divider to match the input voltage range of the ISO224.

The high input voltage range and the high common-mode transient immunity of the device ensure reliable and

accurate operation even in high-noise environments.

Figure 9. Using the ISO224 for AC Voltage Sensing

9.2.1 Design Requirements

Table 1 summarizes the typical design requirements for an AC power line voltage sensing application.

Table 1. Design Requirements

PARAMETER

VALUE

50 V to 750 V

Bandwidth

600 Hz (minimum)

1 mA (maximum)