Soft errors (primarily single-event transients (SET) and single-event upsets (SEU)) are receiving increased attention due to the increasing prevalence of automotive and biomedical electronics. In recent years, several latch designs have been developed for SEU/SET protection, but each has its own issues regarding timing, area, and power. Therefore, we propose a novel soft-error mitigating latch design, called SEM-Latch, which extends QUATRO and incorporates a speed path whereas embedding a reference voltage generator (RVG) for simultaneously improving timing, area, and power in 45nm CMOS process. SEM-Latch effectively reduces the power, area, and PDAP (product of delay, area, and power) by an average of 1.4%, 12.5%, and 8.7%, respectively, in comparison to a previous latch (HPST) with equivalent SEU protection. Furthermore, in comparison to AMSER-Latch, SEM-Latch reduces area, timing overhead and PDAP by 27.2%, 48.2%, and 60.2%, respectively, to provide 99.9999% particle rejection rate for SET protection.