Speaker
Dr
Ken Wyllie
(CERN)
Description
The transmission of data from detectors in future high energy experiments will be driven by a number of requirements. In many cases, raw bandwidth is the strongest of these but other needs such as diverse functionality, compactness, low power and radiation resistance are equally important. The GigaBit-Transceiver (GBT) project has been launched to provide a solution to these problems. The aim is to deliver a chip-set to build a bidirectional optical link transmitting and receiving serial data at 4.8 Gigabit/s.
The GBT project is based on four integrated circuits; a trans-impedance amplifier to receive signals from a photo-diode, a laser driver, an ancillary interface chip, and a transceiver (GBTX) containing a high-speed serialiser and de-serialiser. All of these have been successfully prototyped, and this paper will focus on the design and results from the GBTX prototype. This has been designed in commercial 130 nm CMOS with particular emphasis on enhancing its immunity to single-event-effects, which would otherwise lead to data corruption and link down-time. The chip has been fully characterized in the lab, with bit error rates in data transmission below 10^-15. These and other results will be presented, together with additional functionality included in the chip for the distribution of timing signals and built-in test features. The high speed serial data requires the use of dense flip-chip interconnects on the chip which will be described together with a corresponding custom ball-grid-array package. The paper will conclude with the application of the GBT in the planned upgrade of the LHCb experiment at CERN, where the bandwidth and functionality play a crucial role in this trigger-less data acquisition system.
Author
Dr
Ken Wyllie
(CERN)
