In this paper, a power-efficient, low noise analog front-end (AFE) is presented which employs the chopperstabilized technique. A new instrumentation amplifier structure leads to a high input impedance beyond 10 GΩ at the frequency of 10 Hz. Furthermore, an adaptive DC servo loop (DSL) is proposed which is conditionally activated to minimize the negative impact of this block on the noise performance of the AFE. The integrated input-referred noise of the amplifier is 1.33 μVrms and 1.19 μVrms over the 0.5 Hz–100 Hz frequency range when the DSL is enabled or disabled, respectively. Also, considering different aspects of the AFE, a new comprehensive figure of merit (FOM) is introduced to compare different state-of-the-art biopotential amplifiers. The power consumption and bandwidth of the designed 16-channel AFE are 15.81 μW and 235 Hz, respectively. The circuit is realized in the 180 nm standard complementary metal–oxide–semiconductor technology using a 1 V power supply.

Keywords