Custom integrated front-end circuit for the CMS electromagnetic calorimeter

A wide dynamic range multigain transimpedance amplifier custom integrated circuit has been developed for the readout of avalanche photodiode and vacuum phototriode in the CMS electromagnetic calorimeter for the Large Hadron Collider experiment. The 92-dB input dynamic range is divided into four ranges of 12 bits each in order to provide 40-MHz analog sampled data to a 12-bit analog-to-digital converter. This concept, which has been integrated in rad-hard full complementary bipolar technology, will be described. Experimental results obtained in the lab and under irradiation will be presented along with the test strategy being used for mass production. Index Terms--Bipolar custom integrataed circuits, electromagnetic calorimeter, low noise, wide dynamic range.