Low noise amplifier for MEMS gyroscope readout circuit

The paper presents a two stage low noise amplifier for a MEMS gyro readout circuit. BiCMOS circuitry allows the LNA to achieve low noise level at the working frequency of 15 kHz without using chopper stabilization technique and large biasing currents in the first stage. First stage of the low noise amplifier is a three stage opamp with resistive feedback, first stage of which is a bipolar stage with passive load with input current compensation circuit, second is a single-ended to differential converter, and the third is a class AB output stage. The second stage of the low noise amplifier is a fully differential opamp with resistive feedback. Proposed circuit is designed in 0.25 SiGe BiCMOS technology. Input referred noise voltage at 15 kHz is 8.2 nV/√Hz, gain of the amplifier is 54 dB while the phase shift at 15 kHz is 0.3°.