GT Readout Platform: Testing and Bring-Up

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Resistance measurements with cable attached

• Cable was produced in-house, see TIDIDECS-114 - Getting issue details... STATUS
• There are no serial number on the cables, so for now only using one and assigning it "Cable 01"
• Measuring between banana connector on the cable and test points on the board

Resistance measurements with analog and digital boards mated

Measuring on test points on the analog board.

Voltage measurements with analog and digital boards mated

• FPGA is not programmed.
• All power rails are not powered up yet on the digital board, see Issue #3.
• All power rails on the analog board are disabled by default due to the pull-down resistor R21.

Simplified virtual I/O gateware for the FPGA

Only digital board

• Before programming the FPGA
  • Current consumption: 327 mA at 24 V on P24V0D
  • Temperature: Stable at around 28C with fan blowing on the bottom of the board (not FPGA side)
• After programming the FPGA
  • Current consumption: 336 mA at 24 V on P24V0D
  • Temperature: Stable at around 29C with fan blowing on the bottom of the board (not FPGA side)
• Virtual IO
  • prsntAnalogL and prsntCarrierL both are high indicating no boards are plugged in
  • hwRev is correct: 0b0001
  • hardwareIo[7:4] works

Digital and analog board

• After programming the FPGA
  • Current consumption: 338 mA at 24 V on P24V0D
  • Temperature stable at around 32C now due to analog board in the way of the airflow to the digital board
• prsntAnalogL is now low indicating that the analog board is plugged on
• Toggling pwrEnable HIGH should turn on all the power supplies on the analog board
  • This includes supplies on the P24V0A power rail also so this must be provided from the external supply
  • Toggling the pwrEnable HIGH
  • Current consumption:
    • 440 mA at 24 V on P24V0D
    • 47 mA at 24 V on P24V0A
  • Probing on analog board:
    • P5V0A FIRST = 4.978 V
    • P5V0D FIRST = 5.013 V
    • P1V8A FIRST = 1.816 V
    • P1V8D FIRST = 1.803 V
    • P1V8D = 0.494 V
    • P3V3D = 0 V
    • P3V3A = 0 V
    • P1V8A = 0 V
    • P2V5 AVDD = 0 V
    • P2V5A SINK = 0 V
    • P0V8 DC BIAS = 0 V
  • → Something is not working on the analog board and the power sequencing!
    • Issue identified, see Issue #1
    • Gave all three analog boards to the workshop on 2024-04-26 for rework
• Reworked analog board received back on 2024-04-29
  • Testing 38-C00-01 and 39-C00-01
    • Current consumption after programming and enabling power to analog board:
      • 446 mA at 24 V on P24V0D
      • 192 mA at 24 V on P24V0A
    • Probing on analog board:
      • P5V0A FIRST = 5.003 V
      • P5V0D FIRST = 4.990 V
      • P1V8A FIRST = 1.807 V
      • P1V8D FIRST = 1.801 V
      • P1V8D = 1.808 V
      • P3V3D = 3.280 V
      • P3V3A = 3.294 V
      • P1V8A = 1.800 V
      • P2V5 AVDD = 2.517 V
      • P2V5A SINK = 2.529 V
      • P0V8 DC BIAS = 0.807 V
      • P1V3 A1VDD = 1.303 V
      • P1V3 A2VDD = 1.303 V
      • P1V3 A3VDD = 1.305 V
      • P1V3 A4VDD = 1.302 V
      • P0V6 A1SINK = 0.616 V
      • P0V6 A2SINK = 0.624 V
      • P0V6 A4SINK = 0.616 V
      • P0V6 A3SINK = 0.619 V
    • → All looks good!
    • Temperature stable at around 36C with fan blowing on the top of the analog board, not directly on the FPGA

Digital, analog and carrier board

• prsntCarrierL is now low indicating that the carrier board is plugged on

Mounted LEAP transceiver

• Mounted a LEAP transceiver on board 38-C00-01 on 2024-04-30
  • Instructions from Detector assembly instructions#Connectingtransceiver
• Only powering up the digital board by itself:
  • FPGA is not programmed
  • 481 mA at 24 V on P24V0D
    • Compare this to 327 mA without the transceiver

Mounted fiber optical pigtail

• Mounted a fiber optical pigtail on board 38-C00-01 on 2024-05-01
  • Instructions from Detector assembly instructions#Connectingthetransceivercable

Mounted boards to cooling block

• Mounted digital board 38-C00-01 and analog board 39-C00-01 on 2024-05-1
• Started with the analog board:
  • Cut two pieces of 1 mm thick thermal pad that covered most of the components
  • Added additional 1 mm thick thermal pad over the regulators on the left side of the board as shown below
  • Added some 3 mm thick thermal pad over the regulators on the right side of the board
• Screwed the analog board into the cooling block
• Then the digital board:
  • Cut one 1 mm thick thermal pad for the FPGA
  • Cut one 1 mm thick thermal pad for the big and tall regulator
  • Cut one 1 mm thick thermal pad covering all the other regulators on the left side of the board as shown below
  • Cut some 3 mm thick thermal pads and placed over clock components on the right side of the board
• Carefully plugged in the digital board into the analog board through the connector
• Tightened the screws on the digital board but not all the way since the distance is smaller between the two boards on the cooling block
  • Tightening more would probably cause a lot of stress on the connector which sets the height of 17.5 mm between the board
• Powered everything up
• LEAP transceiver gets too warm after only about 2 min of being on even with a fan blowing above
  • This needs to be connected to the cooling block somehow
  • Could also use the LEAP with a heatsink for use in the lab with a fan
• The original cooling plate for the LEAP transceiver does not fit as is because it was based on the previous board design
  • Hacked it together by drilling and tapping a hole into the copper cooling block
  • Added a 3 mm thermal pad between the LEAP transceiver and the plate to fill out the gap
  • Seems to work OK, with the plate heating up slowly and the LEAP not feeling too hot

First full system test