UPDATE 1-ON Semiconductor Q1 profit beats Street view

(Recasts; adds details, share movement)

May 6 (Reuters) - ON Semiconductor Corp (ONNN.O: Quote, Profile, Research) posted a better-than-expected quarterly profit, helped by its acquisition of AMIS Holdings Inc, and forecast second-quarter revenue above Wall Street expectations, sending its shares up 8 percent after the bell.

"Backlog levels at the beginning of the second quarter of 2008 were up from backlog levels at the beginning of the first quarter... and represent over 85 percent of our anticipated second quarter 2008 revenues," CEO Keith Jackson said.

The company sees total revenue of $545 million to $560 million for the second quarter. Analysts' average forecast is $417.1 million, according to Reuters Estimates.

For the first quarter, the company earned $20.8 million, or 7 cents a share, compared with $54.0 million, or 18 cents a share, a year ago.

Excluding items, it earned 21 cents a share.

Revenue rose 3 percent to $421.9 million. Excluding the impact of the AMIS acquisition, which closed on March 17, the company had standalone revenue of about $396.4 million.

Analysts on average expected earnings of 14 cents a share before exceptional items, on revenue of $385.6 million, according to Reuters Estimates.

ON Semiconductor shares, which closed at $7.81 Tuesday on Nasdaq, were trading at $8.45 after the bell. (Reporting by Jennifer Robin Raj in Bangalore; Editing by Himani Sarkar)