Low noise amplifier for integrated angular acceleration sensor

This paper presents a two stage low noise chopper amplifier for integrated angular acceleration sensor signal processing circuit which consists of amplifiers, phase-locked loop and automatic gain control. Capacitor feedback amplifier circuit is one of the most suitable for CMOS technology however capacitor amplifier with chopped op-amp has poor low frequency performance because of parasitic resistive coupling between inputs of the op-amp. In presented amplifier modulators are placed outside capacitive feedback which improves noise and gain performance. Proper gain distribution between stages contributes to minimizing output noise and phase shift. Chopper ripple is of no concern because of low pass filters in phase-locked loop in signal processing circuit. Proposed circuit is designed in 0.18 CMOS technology. The chopper amplifier consumes 1.75 mA current. Input referred noise voltage at 15 kHz is 8.2 nV/√Hz, gain of the amplifier is 53 dB while the phase shift is 0.6°.