Compact GaN-Based DCFL Amplifier With Direct-Coupled Loads for Wide-Temperature Applications

Compact amplifier with stable performance across wide temperature ranges is promising for the high-temperature electronics. This work aims to demonstrate a direct-coupled FET logic (DCFL)-based amplifier using monolithic D-mode GaN HEMT loads, optimized for robust operation from 25 °C to 300 °C. The amplifier integrates a p-GaN HEMT driver with varying-width D-mode GaN HEMT loads (250Ω-50Ω) to evaluate voltage transfer characteristics (VTC), noise margins, and frequency response. Experimental measurements confirm minimal temperature sensitivity in key DC parameters, consistent VOH of 5 V, and stable gain up to ~1 kHz with a 3-dB cutoff frequency of ~0.1 MHz. Benchmarking against prior GaN-based amplifiers highlights the proposed design’s efficiency, requiring only two active devices while maintaining competitive gain and superior thermal resilience. These results validate the DCFL amplifier’s suitability for high-temperature applications in aerospace, automotive, and power conversion systems.