Power-supply/ground-ripple rejection capability of the SMA2SH preamplifier array for a silicon micro-strip detector

The noise characteristic of the SMA2SH-series preamplifier array has been updated in terms of its sensitivity to external disturbances. An eight-channel version of the SMA2SH preamplifier was employed for the evaluation. In order to distinguish a power-supply disturbance from that coming from ground, we employed two configurations of an internal biasing circuit for the preamplifier. We ultimately found a scheme to eliminate external disturbances, where we obtained a noise level of 1000 electrons at 30 pF of the detector capacitance with a noise slope of 20 electrons/pF.