Abstract: A two pin CMOS oscillator includes an improved input protection circuit which includes pairs of back-to-back diodes coupled between the input of an amplifier portion of the oscillator and the two power conductors which energize the oscillator. Provision of the back-to-back diode pairs permits use of an internal timing capacitor coupled between the output and input of the amplifier portion of the oscillator to be partially charged by an external timing resistor to a switching point of the amplifier portion of the oscillator. When the amplifier portion of the oscillator switches, the voltage at the input may be boosted or bootstrapped to voltages considerably beyond the range of voltage between the two voltage conductors. Thus, clipping of the voltage swings at the timing node of the oscillator by the protection circuit is avoided, and improved performance is achieved, especially at high frequencies.