A discriminator with a current-sum multiplicity output for the PHENIX multiplicity vertex detector

A current output multiplicity discriminator for use in the front-end electronics (FEE) of the Multiplicity Vertex Detector (MVD) for the PHENIX detector at RHIC has been fabricated in the a 1.2-/spl mu/ CMOS, n-well process. The discriminator is capable of triggering on input signals ranging from 0.25 MIP to 5 MIP. The frequency response of the discriminator is such that the circuit is capable of generating an output for every bunch crossing (105 ns) of the RHIC collider. Channel-to-channel threshold matching was adjustable to /spl plusmn/4 mV. One channel of the multiplicity discriminator occupied an area of 85 /spl mu//spl times/630 /spl mu/ and consumed 515 /spl mu/W from a single 5-V supply. Details of the design and results from prototype device testing are presented.