High Performance Low Power Pulse-Clocked TMR Circuits for Soft-Error Hardness

The use of pulse-clocked latches has become ubiquitous in commercial unhardened integrated circuits (ICs) both for their performance and power benefits. In this paper, their use in soft-error hardened triple modular redundant (TMR) circuits is presented. The proposed multi-bit, self-correcting, TMR pulse-clocked latch macro provides a low power, high-speed design with high soft-error immunity. The macro includes test modes for delay testing of both individual and TMR copies with minimal area overhead, as well as a non-redundant operating mode. A physical design flow provides spatial separation of redundant logic copies to avoid upsets due to collection in multiple domains. A TMR, 128-bit data, 256-bit key, advanced encryption standard (AES) is fabricated on a 90-nm foundry low-standby power (LSP) process and its hardness verified using error injection simulations and proton beam testing.