A 0.4 Hz-335 MHz 130 dBΩ Transimpedance Amplifier with Tunable-Bias for MEMS Oscillators

The paper presents a 0.4 Hz-335 MHz 130 dB transimpedance amplifier (TIA) for driving capacitive MEMS beam resonators. The proposed TIA is a four-stage topology, consisting of a regulated cascaded amplifier, a NMOS Cherry-Hooper amplifier, a CMOS Cherry-Hooper amplifier, and a Common-Source amplifier. The novel part of this work is a tunable control voltage to maintain an appropriate operating point. Implemented on the SMIC 180 nm CMOS process, the TIA was elaborately designed and shows a simulated gain of 130 dB and, a bandwidth of 335 MHz with TIA input/output parasitic of 0.5 pF. The input-referred noise current of the TIA is 1.3 pA/ Hz at the resonant frequency of 20.18 MHz. The TIA drives the MEMS resonator well and oscillation builds up within 50 with a swing of 2.56 Vpp and the MEMS oscillator shows a simulated phase noise of -124.2 dBc/Hz at 100 kHz offset. The power consumption is 26.76 mW under 3.3V supply.