An analog front-end (AFE) circuit for conditioning a sensor signal is disclosed. The AFE circuit includes a first stage configured to amplify and filter the sensor signal. The first stage comprises a biquadratic filter comprising a first plurality of DC-coupled transconductance amplifiers. The AFE further includes a second stage configured to further amplify and filter the amplified sensor signal, and to compensate a direct current (DC) offset of the first stage. The second stage comprises a second plurality of AC-coupled transconductance amplifiers. Each transconductance amplifier of the first plurality and of the second plurality has a programmable transconductance and comprises a plurality of subthreshold-biased transistors.