Design and construction of an ALICE SDD end-ladder prototype board

The paper explains the design and the construction of a prototype of an end-ladder card for the ALICE SDD experiment. The final end-ladder card will receive an input dataset from the front-end electronics and will transmit the elaborated dataset through an optical channel to the counting room. The proposed prototype card includes an actual ALICE SDD end-ladder prototype card with all the components foreseen for the final version. This is designed together with an external larger card with all the testing equipment required for measurements in lab. The end-ladder card matches the final dimensions while the external larger one provides all the connectors and an optical receiver mirror unit for an easy-to-use complete system. The final optical modules are provided into the end-ladder prototype card and are composed of 2-photodiodes and 1-laser single-mode 1310 nm with their single mode fibers. Once the front end dataset enters the prototype, a small size digital rad-hard chip carries out a bidimensional compression and acts as a JTAG switch for the front end electronics. The incoming dataset is then compressed, packed, serialized and output via an 800 Mb/s optical link to the external receiver card of the prototype. The mirror receiver card deserializes the stream and reconstructs the original dataset before being compressed.