Ring oscillator using an RTD-HBT heterostructure

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 RT D-HBT inverters using 2 x 5 mum(2) HBT technology. The center oscillation f requency 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. Ri ng oscillators have been widely employed in phase-locked loops for clock an d data recovery and in frequency synthesis in communication systems because they are easy to design and very reliable. With CMOS technology, the oscil lation 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 f abricate ring oscillators operating at higher speeds with lower power consu mption.