Molybdenum gate MOS applied to an AM/FM digital frequency synthesizer

An n-channel molybdenum self-aligned gate MOS technology has been developed and applied to an AM/FM digital frequency synthesizer. A high-frequency programmable divider operating at 180 MHz has been achieved by the use of molybdenum, low parasitic capacitance structures and zero-threshold MOS transistors, while maintaining conventional design rules. Molybdenum gate MOS has enabled the realization of a single-chip system, which consists of a directly programmable divider for the AM/FM local oscillators, a reference counter, a phase comparator, a circuit for dial tuning, and memories for storing the frequencies for 16 stations. A differential comparator has been fabricated on the LSI chip to simplify digital tuning in the receiver.