Novel resonant-tunneling multiple-threshold logic circuit based on switching sequence detection

We present a novel multiple-threshold circuit using resonant-tunneling diodes (RTDs). The logic operation is based on detecting a switching sequence in the RTD circuit. This scheme enables us to increase the number of threshold voltages by more than a factor of two compared with previous RTD-based MVL circuits. SPICE simulation shows that the circuit can operate at a clock frequency as high as 10 GHz. A 4-bit flash analog-to-digital converter, which uses the present circuit as a quantizer, is also discussed.