** Semiconductor solutions provider Allegro MicroSystems ALGM.O shares up 9% at $29.19 in premarket

** Company turns down a $6.9 billion takeover approach from Onsemi ON.O

** ALGM rejects offer saying it was "inadequate" as the company refused yet another approach from the larger rival

** Chipmaker Onsemi said on Wednesday it offered $35.10 for each Allegro share in a deal that would help it ride out a prolonged slump in demand for automotive chips

** The offer was at a premium of about 31% to Allegro's closing on Wednesday

** As of last close, ALGM has gained ~23% YTD

(Reporting by Pritam Biswas in Bengaluru)

((Pritam.Biswas@thomsonreuters.com))