ON Semiconductor Corp. made its pursuit of Allegro Microsystems Inc. public on Wednesday after disclosing an unsolicited $6.9 billion bid that includes debt.

U.S.-based Allegro MicroSystems (ALGM) rejected a $6.9 billion takeover bid from its larger rival Onsemi, formerly known as ON Semiconductor

Allegro MicroSystems said On Semiconductor’s recent acquisition offer that values it at $6.9 billion is “inadequate.”Scottsdale, Ariz.-based On Semiconductor, also known as Onsemi, said it has offered to take over Allegro at $35.