Ring oscillator using an RTD-HBT heterostructure

Abstract

We report the first ring oscillator design using a Resonant Tunneling Diode-Heterojunction Bipolar Transistor (RTD-HBT) heterostructure for high-speed and low-power applications. The ring oscillator consists of three-stage RTD-HBT inverters using 2 x 5 mum(2) HBT technology. The center oscillation frequency of the oscillator is 17.32 GHz and it consumes only 2.3 mW from a 1.3-V power supply. The phase noise is -88.8 dBc/Hz at a 1 MHz offset and -95.2 dBc/Hz at a 10 MHz offset under the above-mentioned bias condition. Ring oscillators have been widely employed in phase-locked loops for clock and data recovery and in frequency synthesis in communication systems because they are easy to design and very reliable. With CMOS technology, the oscillation frequency is limited to the sub-GigaHertz to GigaHertz range due to the low speed of CMOS. With RTD-HBT technology, we are able to design and fabricate ring oscillators operating at higher speeds with lower power consumption.