R. Garg, S. Khatri,
"A Novel, Highly SEU Tolerant Digital Circuit Design Approach,"
IEEE International Conference on Computer Design (ICCD) 2008, Lake Tahoe, CA, October 12-15 2008, pp. 14-20.
In this paper, we present a new radiation tolerant CMOS
standard cell library, and demonstrate its effectiveness in
implementing radiation hardened digital circuits. We exploit the
fact that if a gate is implemented using only PMOS (NMOS)
transistors then a radiation particle strike can result only in
logic a 0 to 1 (1 to 0) flip. Based on this observation, we derive
our radiation hardened gates from regular static CMOS gates. In
particular, we separate the PMOS and NMOS devices, and split the
gate output into two signals. One of these outputs of our radiation
tolerant gate is generated using PMOS transistors, and it drives
other PMOS transistors (only) in its fanout. Similarly, the other
output (generated from NMOS transistors) drives only other NMOS
transistors in its fanout. Now, if a radiation particle strikes one
of the outputs of the radiation tolerant gate, then the gates in
the fanout enter a highimpedance state, and hence preserve their
output values. Our radiation hardened gates exhibit an extremely
high degree of SEU tolerance, which is validated at the circuit
level. Using these gates, we also implement circuit level hardening
based on logical masking, to selectively harden those gates in a
circuit which contribute most to the soft error failure of the
circuit. The gates with a low probability of logical masking are
replaced by SEU tolerant gates from our new library, such that the
digital design achieves a 90% soft error rate reduction.
Experimental results demonstrate that this reduction is achieved
with a modest layout area and delay penalty of 62% and 29%
respectively, for area mapped designs. In contrast with existing
approaches, our approach results in SEU immunity for extremely
large critical charge values (>650fC).
Associated Project(s):SHIELD (Smuggled HEU Interdiction through Enhanced anaLysis and Detection): A Framework for Developing Novel Detection Systems Focused on Interdicting Shielded HEU