A new type of relaxation oscillator is presented that combines excellent control linearity with low timing jitter. By using an alternative for the Schmitt trigger, the jitter caused by threshold level noise can be significantly reduced compared to a conventional relaxation oscillator, under equal conditions of control linearity. Circuits realized in a 0.8-μm CMOS process show a typical measured distortion in the control characteristic of HD2 = -67 dB and HD3 = -90 dB (Δf = 500 KHz), without using any feedback linearization techniques. The measured phase noise is -102 dBc/Hz at 10-kHz offset at fosc = 1.5 MHz (65-ppm rms jitter) for a total supply current of 360 μA.
|Number of pages||9|
|Journal||IEEE journal of solid-state circuits|
|Publication status||Published - Jun 2002|