Development of T3Maps adapter boards By: Jeremy Sandoval, University of Washington, seattle, wa

Project Purpose & Motivation Goal: To design and build a Printed Circuit Board (PCB) adapter card for T3MAPS testbeam DAQ System T3MAPS: A CMOS sensor with readout circuit and pixel sensor integrated into a single wafer. The R&D effort is to improve its radiation hardness tolerance for future ATLAS tracker upgrade DAQ requirement: 1.5V CMOS single-ended signal Multi-channel parallel I/O 5kHz to 50MHz readout speed LBNL T3MAPs Test Setup

T3MAPS Simple DAQ Hardware requirements First version of the T3MAPS DAQ is implemented on the Digilent Atlys FPGA board and does not include all of the features of LBNL setup. There are 8 command signals FPGA to T3MAPS and 1 data signal T3MAPS to FPGA. T3MAPS uses 1.5V logic and is powered off of a 1.5V supply, therefore necessary to use an Integrated Circuit (IC) to regulate voltage: TPS77615. Chose to interface with the VHDCi connector of the FPGA. Can select 2.5V or 3.3V logic, and can send power through the connector. Need a voltage translator for safely communicating with T3MAPs: SN74AVC, 8bit and 1bit versions FPGA VHDCi Connector Diagram

Breadboard Circuits 1.5V LDO Test Circuit Before designing a PCB for the hardware interface, it is necessary to test each circuit on a breadboard. Any modifications to the circuits can be quickly done saving time and money in the long run. Two main circuits: Voltage Level Shifting circuit and a Low Dropout Voltage Regulator. Voltage translation from 2.5V to 1.5V logic for 8 command signals and 1.5V logic for 1 data in signal. LDO to provide regulated 1.5V to the IC’s and to T3MAPS itself. 1.5V LDO Test Circuit

Eagle Schematic & board layout Chose to use EAGLE PCB software for this project. PCB Design Considerations: Create easy to read schematics Before starting the layout, identify the features and limitations of the PCB manufacturing service Research connector options and choose parts that are easily available or not too expensive Used polarized power connectors to prevent IC damage Create accurate smd footprints based off datasheet Include signal test points for easy signal probing LEDs are useful to verify when the board is powered Use wider trace sizes (> .32”) for traces carrying significant current Include mounting holes Arrange parts to minimize excessive trace lengths for high speed signals Include features such as a jumper to select between external and alternate power sources Final step: Add ground planes on top and bottom layers and connect them with vias.

Schematic

Design review and Changes Before a final design for the T3MAPS Adapter Board is submitted for manufacturing, the board design is circulated with the group. Need to circulate separate pictures of the top and bottom layers as well as a picture of the circuit schematic. Any changes can be quickly made and a new design circulated. This T3MAPS Adapter board went through 2 revisions before a final design was created. Top Layer Bottom Layer

PCB Fabrication Information Placed PCB order through Advanced Circuits Reasonably priced: $55 order total when using the student discount Board within 2 weeks: 5-day turn-around time + 5-day shipping Bill of materials should be used to place an order for the needed electronic components. For this board, I used Mouser over Newark or Digikey because they had the lowest overall order price Ordering a PCB requires you to export the Gerber files of your board. There are hundreds of layers used in Eagle, but the manufacturer only needs certain information contained on certain layers such as the drill locations and sizes. Many tutorials exist for exporting Gerber files.

T3MAPS adapter Construction Once the PCB arrives, you want to carefully visually inspect each trace, hole, and pad for any errors. Next, soldering all of the electronic components and connectors to the board. Make sure to use a fine tip soldering iron for fine-pitch components Make sure that the solder reflows properly such that there is a metal to metal connection from the component pin to smd pad. Avoid solder bridges (i.e. solder blobs connecting multiple pins that shouldn’t be) Fully Constructed Adapter Card

Adapter Card Testing… Several different hardware tests have been performed (next presentation)