Low noise amplifier for mems capacitive transducers

Abstract

This application relates to amplifier circuitry for amplifying a signal from a MEMS transducer. A super source follower circuit (40) is provided which includes a feedback path from its output node (Nout) to a control bias node (BC) in order to provide a preamplifier signal gain that may be greater than unity. A first transistor (M1) is configured to have its gate node connected to an input node (NIN) for receiving the input signal (VIN) and its drain node connected to an input node (X) of an output stage (A). The source node of the first transistor is connected to the output node (NOUT). A current source (I2) is configured to deliver a current to the drain node of the first transistor (M1), wherein the current source (I2) is controlled by a bias control voltage (VBC) at the bias control node (BC). A feedback impedance network (Z1) comprising a first port connected to the output node (NOUT) and a second port connected to the bias control node (BC) is provided.

Dependencies are inferred from the claim text.