** Allegro MicroSystems' ALGM.O shares rise 18.5% to $26.83
** The sensor integrated circuits provider is drawing takeover interest from larger competitor ON Semiconductor ON.O, Bloomberg reported on Sunday, citing people familiar with the matter
** ON has been working with advisers in recent months to pursue ALGM, says the report
** ALGM did not immediately respond to a Reuters request for comment
** Separately, last week, ON said it would lay off about 2,400 of its employees worldwide in 2025
** ALGM has a market capitalization of $4.11 bln vs ON's $19.83 bln, according to LSEG data
** Including session's move, ALGM up about 21% YTD
(Reporting by Sanchayaita Roy in Bengaluru)
((sanchayaita.roy@thomsonreuters.com))