APVMUX Test (February 2001)

A hybrid containing six APV25S1 chips and the APVMUX was designed and assembled at Strasbourg. Apart from minor details, this is the final hybrid for the CMS tracker, shown in fig.  with an attached kapton cable. The analog output of the six chips is multiplexed onto three lines by the APVMUX, which is the narrow chip in the center of the hybrid.

Figure: The close-to-final hybrid with six APV25S1 and an APVMUX.

The behavior of the hybrid and in particular the APVMUX was evaluated at HEPHY [67]. Since the multiplexed APV25 output is clocked at $40\,\rm MHz$, the input stage of the VME-ADC was modified by removing a slow amplifier, thus increasing the $-3\,\rm dB$ bandwidth from $50$ to $90\,\rm MHz$.