Optocouplers transmit signals by light through a bulk dielectric that provides galvanic isolation:
The optical elements are slow, have limited life, and the bulk dielectric
limits optocoupler miniaturization. IsoLoop couplers use spintronics and magnetics
rather than optics to transmit data:
Isolators consist of an IsoLoop microscopic coil and an integrated
spin valve made of GMR resistors:
spin valve is spintronicGMR
element with two stable resistance states. The coil creates a magnetic field proportional
to the input current signal across a dielectric film. The field changes the spin
polarization of the spin valve resistor elements and thus their resistance The
spin valve output is amplified and conditioned to produce an isolated replica
of the input signal. Thus IsoLoop Isolators transmit signals by a magnetic field
and electron spin rather than by light and photons.
The entire device is
shielded for immunity to external fields. Ground potential variations are common
to both sides of the field-producing input coil, so they do not generate a current.
Therefore, no magnetic field results, and these variations are rejected, resulting
in a very large common-mode rejection ratio (CMRR) and true galvanic isolation.