• carrusel_obdt_theta_test_1
  • carrusel_obdt_theta_test_2
  • carrusel_obdt_theta_test_3

OBDT Theta Tester

Interface board to a XM105 board for driving I2C signals and measuring voltages through an ADC.

The OBDT Theta Tester is a mezzanine designed to test different OBDT-board interfaces used in the CMS detector. Nevertheless, it may be used for other purposes.
This board fits on a FMC XM105 Debug Card, providing several GPIO ports of a Xilinx FPGA.
The design implements 4 I2C buses, one of them connected to a slave ADC device (AD7997). Each of them includes a dual bidirectional voltage-level translator (PCA9306DC1).
The ADC digitizes several input analog voltages, as well as other internal voltages.
It also includes an optocoupler (ACPL-227-50BE) which interconnects an external circuit with a FPGA GPIO output port.
The firmware currently under development will implement 4 I2C slaves and 1 I2C master to control the ADC device and some loopback routines to check all the interfaces. 


This PCB has been designed using Altium 17


  • OBDT Theta Tester schematics
  • OBDT Theta Tester gerber files
  • OBDT Theta Tester Altium project