Design and performance of the ABCD chip for the binary readout of silicon strip detectors in the ATLAS Semiconductor Tracker

The ABCD design is a single chip implementation of the binary readout architecture for silicon strip detectors in the ATLAS Semiconductor Tracker. The prototype chip has been manufactured successfully in the DMILL process. In the paper we present the design of the chip and the measurement results. The basic analogue performance of the ABCD design has been evaluated using a prototype SCT module equipped with the ABCD chips. The digital performance has been evaluated using a general purpose IC tester. The measurements confirmed that all blocks of the ABCD design are fully functional and the chips meet all basic requirements of the SCT. Wafer screening has been performed using a customised wafer tester. The set-up allows measurements of all analogue and digital parameters at the nominal clock frequency of 40 MHz as well as evaluation of speed margins for the digital blocks. The ABCD chips have been irradiated separately with X-rays up to a total dose of 10 Mrad, with neutrons from a nuclear reactor up to a fluence of 2x10(14) n/cm(2) and with a high energy proton beam up to a fluence of 3x10(14) p/cm(2). The test that were performed confirmed satisfactory radiation hardness of the DMILL technology and of the ABCD design up to the radiation levels expected in the SCT.