Fairchild Semiconductor International Inc. says it has a received an unsolicited offer to buy its business, topping its existing deal with ON Semiconductor.

The bidder is identified in SEC documents only as "Party G."

The new offer of $21.70 a is valued at roughly $2.46 billion based on Fairchild's 113.4 million shares outstanding.

Fairchild agreed in November to be bought by ON Semiconductor for $20 per share, or about $2.27 billion.

Fairchild's board of directors said Tuesday that it is reviewing the new offer but has not changed its recommendation supporting of the with ON Semiconductor.

Shares in Fairchild, which is based in San Jose, California, ended Tuesday up 3 cents at $20.01