SMQIE: Challenges associated with a low frequency charge integrator and encoder211 for the CDF II Calorimeter

摘要

The SMQIE is the newest member of the QIE family of integrated circuits. It has211u001ebeen developed specifically for the Shower Max Detector upgrade of the CDF Plug 211u001eand Central Calorimeters at Fermilab. Like its predecessors, it converts charges 211u001eover a wide dynamic range with a variable resolution. Unlike its predecessors it 211u001econtains its own Flash, trigger delay pipeline and buffer area. Furthermore, it 211u001eoperates both at a lower frequency and with only a simple 5-volt power supply. 211u001eThe simultaneous requirements of low frequency and reduced voltage force the 211u001efront end into a low current, high impedance regime. Specialized circuitry is 211u001enecessary to prevent charge slopped-over into subsequent time slices. The 211u001econsiderable amount of digital circuitry monolithic with the analog front end 211u001emakes for a noisy substate. Specialized circuitry and layout techniques are 211u001enecessary to keep this chip from being noise-limited. The final design is a two-211u001echannel single-ended Charge Integrator and Encoder (QIE) that operates at a 211u001efrequency of Integrator and Encoder (QIE) that operates at a frequency of 7.6MHz 211u001ewith a least significant bit resolution of 15 fC in its lowest range.