IL711/IL712/IL721

10

NVE Corporation

11409 Valley View Road, Eden Prairie, MN 55344-3617

(952) 829-9217

www.nve.com

YouTube.com/NveCorporation

iso-apps@nve.com

Application Information

Isolator Operation

An equivalent circuit is shown below:

Data

In

Data

Out

Field

Figure 4. IL711 / IL712 / IL721 equivalent circuit (each channel).

Isolator Signal Path

The GMR isolator signal path starts with a buffered input signal that is driven through an ultraminiature coil. This generates a small magnetic

field that changes the electron spin polarization of GMR resistors, which are configured as a Wheatstone bridge. The change in spin polarization

of the resistors creates a bridge voltage which drives an output comparator to construct an isolated version of the input signal.

Small Size, High Speed, and Low EMI

The coil, GMR, and circuitry are integrated to allow small packages. GMR is inherently high speed and low distortion, and unlike transformers,

does not rely on energy transfer, so power is low and EMI emissions are minimal.

High Magnetic Immunity

GMR provides large signals which improve magnetic immunity, and the Wheatstone bridge configuration cancels ambient common-mode

magnetic fields, further enhancing immunity to external magnetic fields.