Patent attributes
A signal isolator apparatus includes a first substrate for supporting input circuitry including a high frequency oscillator circuit for receiving an input signal, a second substrate for supporting output circuitry including a detector circuit for providing an output signal; and a third substrate having parallel conductive layers separated by insulation. The third substrate has an upper conductive shield formed in a second conductive layer and a lower conductive shield formed in a fifth conductive layer. A transformer is formed between the upper and lower conductive shields and includes a primary winding formed in a third conductive layer and a secondary winding formed in a fourth conductive layer. The oscillator circuit is connected to the primary winding and adapted to excite the primary winding at a first frequency in response to the input signal, and the detector circuit is connected to the secondary winding and adapted to selectively sense the first frequency and provide the output signal. The third substrate is arranged to form a bridge connection between the first and second substrates.