A low-power MOS tetrode

An MOS tetrode has been developed to operate at low power dissipations (typical drain currents from 2 to 5 milliamperes and drain voltage of 6 volts) for use in communications receivers operating in the frequency band from 30 to 76 megacycles per second. Power gains in excess of 20 dB have been obtained at 100 megacycles per second with noise figures in the 2-to-4-dB range. Two gates are provided for signal input and agc control. The agc gate operates in a reverse-biased condition. The device offers excellent crossmodulation distortion characteristics, large dynamic range, and low dissipation, and operates over a 40-dB agc range in an rf circuit. It has very low feedback, together with a high gate-breakdown field (greater than 10⁷volts per centimeter) to resist burn-out. The dual full-gate structure provides excellent voltage and temperature stability during cutoff and storage life-tests. This paper discusses device characterization and design.