Alpha particle immune ECL latches

As lithography has scaled down to 1 mu m and lower, ECL (emitter coupled logic) latches which had been immune to alpha particles in previous technologies have become susceptible. Experimental and theoretical work has developed techniques to restore immunity without sacrificing performance or complexity. The authors first give background theory on this topic and compare simulations to actual results from accelerated soft error rate testing. They then describe an alpha sensitivity test chip and show experimental results. Operation of the shared current source (SCS) design is discussed, and tradeoffs between alpha immunity and performance are described. The SCS circuit technique achieves alpha immunity by reducing the current through the feedback emitter followers attached to the susceptible collector nodes.<
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