1 SEU hardening of CNFGMEM CPPM, Université de la méditerranée, CNRS/IN2P3, Marseille, France

2 13/07/2011 FEI-4 Design Collaboration Meeting Global register Memory 32 x 1 32 bits A0A0 A1A1 A2A2 A3A3 Buffers Address decoder Lines (x) WE Data inData out L 0 L 31  Address : 5 bits  Memory for 1 bit data  Can be easily extended to 16 bits data TRL latch A4A4 Loadi =L i and WE readi =L i and WEbar To config Datain

3 13/07/2011 FEI-4 Design Collaboration Meeting SEU results  During SEU test at CERN, Sasha observed strange properties for events with Global Register  12 of such events classified as "Write glitch" were observed  Variable Writen(hex) Read(hex) 1)errmask0 FFFF FFFE 2)prmpvbp_l )lvdsdrvvos 69 6D 4)plsrvgoamp FF FB 5)amp2vbpfol )pllibias )bonndac ED CD 8)dac8spare )pllibias )bonndac ED CD 11)errmask1 FFFF DFFF  Only One bit is concerned each time  Rate is event/spill  We estimate that only to event/spill attributed to a “true” SEU in the Triple DICE latch  For the others we assume that are the consequence of internal glitches

4 13/07/2011 FEI-4 Design Collaboration Meeting Memory Cell  A glitch in the internal NAND or inverter causes a glitch in the load signal  In this case the current value on the data bus is copied in the memory (we have to check this assumption)

5 13/07/2011 FEI-4 Design Collaboration Meeting Memory cell layout  We still have some space in the memory cell layout

6 13/07/2011 FEI-4 Design Collaboration Meeting What can we modify ?  Increase the area of the gates used to generate the load  Add a load capacitance at the internal load path  Introduce a delay between load signal of each latch  Depending on the option, this work can necessitate to 1 week of work including all verifications  Risk : minor