A 125 dBΩ 1.1 GHz Transimpedance Amplifier for 150 MHz Capacitive MEMS Disk Oscillator

As a candidate for the reference frequency source of 5G/6G communication transceivers, capacitive MEMS resonators have very high insertion loss. This paper proposes an ultrahigh gain wideband transimpedance amplifier (TIA) for the 150 MHz capacitive radial contour-mode MEMS resonator. Using active shunt-shunt feedback and 5-stage tunable Cherry-Hooper amplifiers, the post-simulated gain and bandwidth of the TIA is 125 dBΩ and 1.1 GHz, respectively. The TIA works well with the resonator, and the MEMS oscillator builds up within 3 μs with a swing of 1 Vpp. The post-simulated phase noise is -95 dBc/Hz at 1 kHz offset and -117 dBc/Hz at 10 kHz offset after the automatic-gain control loop is turned on. Implemented on 0.18 μm CMOS process, the TIA consumes 15 mW under a 1.8 V supply.