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

2. 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

3. 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

4. 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

5. 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.

6. Schematic

7. 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

8. 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.

9. 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

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