The paper proposes a complete self-timed functional tolerance element - ST FCT. It's described results of the functional simulation, verification of semi-modular, as well as an example of the synthesis of self-timed circuits in CAD MultiSim and comparison of performance at different supply voltages. Application of the proposed element allows the synthesis of self-timed circuits in a redundant fault-tolerant basis preserving functional completeness in terms of failures, enables the automatic synthesis of custom self-timed combinational circuits, which could remain operational state at reduced voltage. Key words: self-timed circuits, reduced supply voltage, functionally complete tolerance element, CAD, semi-modular.
