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This work investigates a low-power transimpedance amplifier (TIA) topology suited for VHF micromechanical oscillator applications. The TIA circuit comprises of a regulatedcascode (RGC) transimpedance gain stage and an inverterbased wideband Cherry-Hooper amplifier with capacitive peaking. The circuit was designed using TSMC 0.18m CMOS technology, exhibiting mid-band gain of 99dB and 3dB bandwidth of 280MHz while dissipating only 1.57mW from a 1.5V supply. A linear RLC equivalent model extracted from a practical 48MHz Lamé-mode resonator with Q>40,000 was interfaced with the TIA circuit in a series-resonant oscillator configuration, showing simulated phase-noise less than128dBc/Hz at 1kHz offset.

A two-port silicon-based micromechanical beam resonator driven at its high-stiffness locations has been proposed with enhanced power handling as compared with the same resonator but using conventional drive/sense configurations. The key to attaining superior power handling relies on the electrode arrangements where critical handling power (or Duffing-nonlinear bifurcation power) becomes much higher by driving the resonator at its high-stiffness locations than low-stiffness areas. In this work, resonators using high-stiffness driving approach exhibit around 20× (20 times) power handling improvement as compared to low-stiffness driving counterpart while the motional impedances in both cases are the same under linear operation.

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