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We present a novel switched-capacitor, integrator-multiplexing, second-order delta-sigma modulator (DSM) featuring a single differential difference amplifier (DDA). Power consumption is low and resolution is high when this DSM is used for portable electroencephalographic applications. A single DDA (rather than a conventional operational transconductance amplifier) with appropriate switch and capacitor architectures is used to create the second-order switched-capacitor DSM. The configuration ensures that the resolution is high. The modulator was implemented using a standard 180 nm complementary metal–oxide–silicon process. At a supply voltage of 1.8 V, a signal bandwidth of 250 Hz and a sampling frequency of 200 kHz, simulations demonstrated that the modulator achieved an 82 dB peak signal-to-noise–distortion ratio and an effective number of bits of 14. [ABSTRACT FROM AUTHOR]