This paper evaluates different trade-offs of N-modular redundancy technique in SRAM-based FPGAs. Redundant copies of the same module were implemented and the outputs voted by self-adapted majority voter. The redundant design was exposed to neutrons and the error rate was evaluated. Results in cross-section, area and power consumption were analyzed for different numbers of redundant modules, ranging from 3 copies (standard TMR) up to 7 copies.