Amplifier circuitry

Amplifier circuitry for amplifying an input signal from a MEMS capacitive sensor comprising:

• a first amplifier having an input for receiving the input signal and configured to output, at a first amplifier output, a first output signal based on the input signal;
• a second amplifier configured to output, at a second amplifier output, a second output signal which varies inversely with the first output signal;
• wherein the first amplifier output is connected to the second amplifier output via first and second impedances so that a voltage at a common-mode node between the first and second impedances is equal to a common-mode voltage of the first and second output signals;
• and
• wherein the second amplifier comprises:
• an input stage having an input terminal connected to a first reference voltage and a feedback terminal connected to the common-mode node;
• and
• an output stage connected between an output terminal of the input stage and the second amplifier output.