SMQIE: A charge integrator and encoder chip for the CDF Run II Shower Max detector

The Technical Design Report for the CDF II Detector calls for the development of an imbedded two-dimensional position sensitive detector sandwiched inside the electromagnetic calorimeter and placed at the shower maximum. The purpose of this detector is to aid in the identification of electrons and photons, to separate photons from π ⁰s, and to help identify electromagnetic showers. This detector is called the Shower Max. In order to achieve CDF´s goals for resolution, timing, power and economy, as well as to fit into the available space, a full-custom integrated circuit was required for the project the SMQIE. The SMQIE has been fabricated in a 1.2 μm CMOS process using vertical NPN transistors in critical areas. It operates without deadtime. Its QIEs have eight ranges and an overall dynamic range of 13 bits. Its FADCs have a 5-bit resolution with a nominal LSB of 31.25 mV. Its Level 1 Trigger delays are 42 beam crossings or approximately 5.5 μs. Its data buffers hold up to four events, each of which can consist of four time slices. Finally, the chip accepts a maximum input charge up to 150 pC with a minimum resolution of 15 fC