A 192 nW 0.02 Hz High Pass Corner Acoustic Analog Front-End with Automatic Saturation Detection and Recovery

We present an acoustic analog front-end with a 100TΩ feedback resistance that is robust to PT variation (1.8× deviation across –40 to 80°C and 0.035× σ/µ across 16 measured samples) and achieves a 3.3× reduction in input referred noise (IRN). It eliminates an input frequency and phase dependent systematic offset introduced by a similar previous technique [5] and introduces automatic saturation detection and feedback resistance modulation for fast amplifier restabilization, yielding 10× improvement in artifact recovery time. The technique was implemented in a 192 nW LNA + PGA + ADC chain.