Performance and future development of the ASDBLR ASIC for the ATLAS TRT

The ATLAS TRT straw tracker will consist of more than 420 K straw tubes filled with a Xenon-based fast gas located in a magnetic field of 2 T. Some tubes will operate at rates in excess of 20 MHz. Stringent signal processing goals $9 have been determined using both simulation tools and measurement standards set by hand tuned discrete component prototypes. These include the ability to detect the earliest clusters from ionizing tracks as well as energetic $9 transition radiation photons without baseline shifts in a low noise and low power design. We report on measurements of two ASIC's fabricated in different processes that appear to be capable of achieving these goals. (2 refs).