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The paper presents the design and measurements of a low noise integrated circuit in a CMOS 130 nm for the readout of a hybrid pixel detector operating in a single photon counting mode. A core of IC contains a matrix of $128\times256$ square shaped pixels of $75~\mu \text{m}$ pitch. Each readout pixel consists of a charge sensitive amplifier (CSA), a shaper, two discriminators, and two 14-bit counters. We present the novel CSA feedback circuitry with an effective resistance of 0.6 $\text{G}\Omega $ and sets of switches, which allows low noise operation and fast return to the CSA output baseline at the same time providing the possibility of operation with a higher flux of input pulses. The measured equivalent noise charge of IC (bump-bonded to silicon sensor) is only 44 $\text{e}^{-}$ rms at 15°C, the offset spread is 5.5 $\text{e}^{-}$ rms and the energy resolution is FWHM = 380 eV @ 8keV, which is currently the best result in single photon counting pixel detectors. The hybrid pixel detector can register up to 107 million photons/mm2 per second, while the power consumption per single pixel is about $42~\mu \text{W}$ .

64 Channel Neural Recording Amplifier with Tunable Bandwidth in 180 nm CMOS TechnologyThis paper presents the design and measurements of low-noise multichannel front-end electronics for recording extra-cellular neuronal signals using microelectrode arrays. The integrated circuit contains 64 readout channels and is fabricated in CMOS 180 nm technology. A single readout channel is built of an AC coupling circuit at the input, a low-noise preamplifier, a band-pass filter and a second amplifier. In order to reduce the number of output lines, the 64 analog signals from readout channels are multiplexed to a single output by an analog multiplexer. The chip is optimized for low noise and good matching performance and has the possibility of pass-band tuning. The low cut-off frequency can be tuned in the 1 Hz - 60 Hz range while the high cut-off frequency can be tuned in the 3.5 kHz - 15 kHz range. For the nominal gain setting at 44 dB and power dissipation per single channel of 220 µW, the equivalent input noise is in the range from 6 µV - 11 µV rms depending on the band-pass filter settings. The chip has good uniformity concerning the spread of its electrical parameters from channel to channel. The spread of the gain calculated as standard deviation to mean value is about 4.4% and the spread of the low cut-off frequency set at 1.6 Hz is only 0.07 Hz. The chip occupies 5×2.3 mm2of silicon area. To our knowledge, our solution is the first reported multichannel recording system which allows to set in each recording channel the low cut-off frequency within a single Hz with a small spread of this parameter from channel to channel. The first recordings of action potentials from the thalamus of the rat under urethane anesthesia are presented.