Digital phase-shift modulation for an isolation buffer in silicon-on-sapphire CMOS

We designed and fabricated a 4-channel digital isolation amplifier in a 0.5mum silicon-on-sapphire technology. The isolation device was fabricated on a single die, taking advantage of the isolative properties of the sapphire substrate. The individual isolation channels can operate in excess of 40Mbps using digital phase-shift-keying modulation. Modulation of the input signal is used to increase immunity to errors at low input data rates. The device can tolerate ground bounces of 1V/mus and isolate more than 800V. The device uses N+1 capacitors for TV channels as opposed to 2N of previous implementations, thus minimizing the coupling silicon area and increasing reliability. Typical applications are in harsh industrial environments, transportation, medical and life-critical systems