An amplifier-discriminator chip for the GLAST silicon-strip tracker

An amplifier-discriminator circuit has been designed for reading data from the silicon-strip detectors of the Gamma Large Area Space Telescope (GLAST). For the 38 pF expected detector loading, an equivalent noise charge (ENC) of 1600 electrons has been demonstrated on a 32 channel chip with a power consumption of under 150 mu W per channel;md a 1 mu s time constant. The typical rms threshold variation was under 750 electrons ENC. These results satisfy the requirements of the GLAST mission.