Ion beam testing of ALTERA APEX FPGAs

摘要

In this work we have studied the effects of heavy ion beam irradiation on a Field Programmable Gate Array (FPGA). We have essentially investigated the Single Event Effects (SEE) induced by ions having Linear Energy Transfer (LET) values between LET = 1.6 MeV·cm{sup}2/mg and LET = 78 MeV·cm{sup}2/mg. Our tests were performed on a device of the APEX family manufactured by Altera Corporation, featuring a SRAM-based configuration memory. The test methodology was based on the implementation of four shift registers (SRs), two of them using Triple-Modular-Redundant (TMR) technique. The Functionality of this circuit was continuously checked during irradiation and every detected error was logged and timestamped by a control system. Very few Single Event Upsets have been detected in the SRs. On the contrary, we have recorded a large number of Single Event Functional Interrupts (SEFIs). SEFIs were induced by SEUs in the SRAM configuration memory. We observed a constant increase of the supply current during irradiation but this effect was not due to Single Event Latch-up's, but to progressive SEU-induced driver contentions or cumulative micro latch-ups. The configuration memory cross section has been calculated from SEFI cross section.