Fully Integrated Digital GaN-Based LSK Demodulator for High-Temperature Applications

We present the first Gallium Nitride (GaN)-based demodulator system dedicated to demodulating Load-Shift Keying (LSK) modulated signals that can operate at high temperature (HT). GaN500 technology is adopted to implement the proposed demodulator. Stable DC output characteristics of epitaxial AlGaN/GaN Heterojunction Field Effect Transistors (HFETs) operating at up to 500 degrees C enable designing HT ICs. Conventional digital gates such as inverters, NAND2, NAND3, delay elements and a D Flip-Flop are employed to implement the proposed demodulator. The demodulation system is fabricated on a 2.67 mm(2) silicon carbide (SiC) substrate and experimentally validated at 160 degrees C, whereas the building blocks (inverters and NANDs) show a stable operation at HT up to 400 degrees C. A minimum of 1 V amplitude difference can be detected between the high voltage level (HVL = +/- 5 V) and low voltage level (LVL = +/- 4 V) of an applied LSK modulated signal to recover transmitted digital data. Two high-voltage supply levels (+/- 14 V) are required to operate the system. Its total power consumption is 3.4 W.