A 1.57mW 99dBΩ CMOS transimpedance amplifier for VHF micromechanical reference oscillators

This work investigates a low-power transimpedance amplifier (TIA) topology suited for VHF micromechanical oscillator applications. The TIA circuit comprises of a regulated-cascode (RGC) transimpedance gain stage and an inverter-based wideband Cherry-Hooper amplifier with capacitive peaking. The circuit was designed using TSMC 0.18μm CMOS technology, exhibiting mid-band gain of 99dBμ 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 than -128dBc/Hz at 1kHz offset.