Progress on the Upstream Tracker Electronics for the LHCb Upgrade

A comprehensive upgrade of the LHCb detector is foreseen for the long shut-down of the LHC in 2019/20 (LSII). As part of the upgrade, the existing TT tracking station in front of the LHCb dipole magnet will be replaced by a new silicon micro-strip detector, the Upstream Tracker (UT). Similarly to the TT, the UT will consist of four planar detection layers covering the full acceptance of the experiment. A new radiation-hard front end readout chip for the UT is being developed in 130 nm TSCM technology. It incorporates 128 input channels with the complete DAQ chain integrated: pre-amplifier, shaper and a 6-bit ADC, pedestal and common-mode subtraction, and zero-suppression as well as data serialization. Measurements on a full-featured prototype chip are well advanced and results from these tests are shown. The silicon sensors are mounted on a light carbon-fibre structure approximately 1.5 m $\times $ 10 cm, called a stave. Output signals and control signals, low-voltage power for the front-end chips and bias voltage for the silicon sensors are transported along the staves via kapton flex cables. Each of these cables carries up to 120 high speed differential pairs with a total of 38.4 Gbps and 8 A of current to power up to 24 ASICs while maintaining a minimal material budget and being easy to manufacture. The design solutions and results of prototype iterations are presented.