A Process and Temperature Compensated Two-Stage Ring Oscillator
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Date: 02-20-2009
Start Time:
2:00pm
End Time: 3:00pm
Speaker: Kumar Lakshmikumar
From:
Conexant Systems, Inc
Location: Interschool Lab - 7th floor - CEPSR
Hosted by:
Prof. Yannis Tsividis
Local positive feedback in a delay element enables a ring oscillator with only two stages to oscillate and produce quadrature clocks. Routh-Hurwitz’s criterion is applied to prove that such a structure can oscillate. An internally generated power supply from a constant-gm bias keeps the free running frequency to within ± 5% from -40 to 125˚C over process variations. The 1.25GHz oscillator in 0.13μm CMOS draws 3.4mA and has a phase noise of -88dBc/Hz at 1MHz offset.
Local positive feedback in a delay element enables a ring oscillator with only two stages to oscillate and produce quadrature clocks. Routh-Hurwitz’s criterion is applied to prove that such a structure can oscillate. An internally generated power supply from a constant-gm bias keeps the free running frequency to within ± 5% from -40 to 125˚C over process variations. The 1.25GHz oscillator in 0.13μm CMOS draws 3.4mA and has a phase noise of -88dBc/Hz at 1MHz offset.