AMPLIFIER CIRCUIT FOR CMOS CRYSTAL OSCILLATOR CIRCUIT AND ITS USING METHOD

摘要

PURPOSE:To correspond to both transmitting signal of a crystal oscillator circuit and clock signal of an external circuit by an amplifier circuit for a CMOS crystal oscillator circuit with simple constitution. CONSTITUTION:The gate terminal of respective MOS transistors 2 and 3 of a CMOS inverter circuit 1 is separated and connected to first and second respective independent external terminals A and B. The output terminal of the CMOS inverter circuit 1 is connected to an internal circuit and connected to a third external terminal C. When the oscillation signal of the crystal oscillator circuit is inputted to the internal circuit, the first and second external terminals A and B are mutually connected, and between the mutually connected common external terminals A and B and the third external terminal C, the crystal oscillator circuit is connected. On the other hand, when a clock signal is inputted to the above-mentioned internal circuit, the first and second external terminals A and B are respectively connected to off powers VDD and VSS to make each corresponding MOS transistor into an OFF condition and the clock signal is inputted to the third external terminal.