A system comprising an integrated multi-axis MEMS inertial sensor architecture. The system can include a MEMS gyroscope having a MEMS resonator and a MEMS accelerometer overlying a CMOS IC substrate. The CMOS IC substrate can include low noise Charge Sense amplifiers to process the sensed signals, programmable gain amplifiers, a demodulator, mixer, an AGC loop circuit coupled to the MEMS gyroscope to drive MEMS resonator. The CMOS IC also includes programmable Quadrature cancellation, Analog and digital phase shifters are implemented in the architecture to ensure quadrature cancellation and demodulation to achieve optimal performance. The AGC loop acts in a way such that generated desired signal amplitude out of the drive signal maintains MEMS resonator velocity at a desired frequency and amplitude while consuming low power. The MEMS gyroscope and accelerometer can be coupled to an input multiplexer configured to operate in a time-multiplexed manner.