0000866291 2020-11-19 2020-11-19 0000866291 false 8-K 001-39675 2021-05-05 ALLEGRO MICROSYSTEMS, INC. DE 46-2405937 955 Perimeter Road 03103 Manchester, NH (603) 626-2300 false false false false Common Stock, par value $0.01 per share ALGM NASDAQ true false