Low noise oscillator having dissimilar MOS gate structures

An oscillator including an oscillating element and a first amplifier connected between an input terminal and an output terminal of said oscillating element, said oscillator comprising:

• said first amplifier has a first P-type transistor and a first N-type transistor both fabricated by a MOS process;
• a gate of said first P-type transistor and a gate of said first N-type transistor are connected together for receiving an oscillating signal from said output terminal of said oscillating element;
• a drain of said first P-type transistor and a drain of said first N-type transistor are connected together for providing a feedback signal to said input terminal of said oscillating element;
• a source of said first P-type transistor is connected to a power supply;
• a source of said first N-type transistor is connected to a ground potential;
• said gate of said first P-type transistor is configured to provide an electrical path between a P-type source diffused region and a P-type drain diffused region;
• said gate of said first N-type transistor is configured to provide an electrical path between an N-type source diffused region and an N-type drain diffused region;
• said first N-type transistor has a gate length longer than a gate length of said first P-type transistor;
• and
• a second amplifier having an input terminal connected to an output terminal of said first amplifier, said second amplifier including a second P-type transistor and a second N-type transistor, said second N-type transistor having a longer gate length than said second P-type transistor.