Abstract. An 8 bit segmented current steering DAC is presented for the compensation of mismatch of sensors with current output arranged in a large arrays. The DAC is implemented in a 1.8 V supply voltage 180 nm standard CMOS technology. Post layout simulations reveal that the design target concerning a sampling frequency of 2.6 MHz is exceeded, worst-case settling time equals 60.6 ns. The output current range is 0–10 μA, which translates into an LSB of 40 nA. Good linearity is achieved, INL < 0.5 LSB and DNL < 0.4 LSB, respectively. Static power consumption with the outputs operated at a voltage of 0.9 V is approximately 10 μW. Dynamic power, mainly consumed by switching activity of the digital circuit parts, amounts to 100 μW at 2.6 MHz operation frequency. Total area is 38.6 × 2933.0 μm2.

A current-mode delta-sigma modulator is presented for electrochemical sensor arrays utilizing a Current Conveyor and a Current Controlled Oscillator (CCO). Second order noise shaping is achieved although a very simple topology is used with only one integrator. The impact of oscillator non linearity is kept low thanks to a pseudo-differential design.Simulations predict an SNDR of 102 dB at 10 kHz bandwidth, 5 MHz sampling frequency, oversampling ratio of 256, and a CCO non-linearity of 1 %. Even at 5% oscillator non-linearity an SNDR of 72 dB is achieved. A feasibility check is accomplished by designing the proposed topology on transistor-level.

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A low-voltage fully differential current-mode continuous time delta-sigma modulator is presented for application in electrochemical sensor arrays. Although a first order topology is realized by using a single differential integrator, second order noise shaping is achieved. A differential quantizer based on current controlled oscillators (CCOs) allows a currentmode implementation with high noise-immunity and low-voltage compatibility. Thanks to the differential design nonlinearity impact on circuit performance is kept low. Moreover, the typical clock-jitter sensitivity for continuous time modulators is addressed by a switched shaped-current feedback DAC. The modulator implemented in 180 nm standard CMOS technology consumes 28μW and achieves an SNDR of 95dB at a signal bandwidth of 10 kHz and an oversampling ratio of 256.

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