ON Semiconductor (NASDAQ: ONNN) recently purchased Sanyo Semiconductor ($1.1 billion in annual revenues) and thus has several thousand employees and several fabs in Japan.

We understand that all employees are safe. We think some of ON Semi's fabs have experienced intermittent power disruptions, making production difficult in the near-term. Some scrap, yield loss, and production downtime are likely in multiple facilities, Craig Berger wrote in a note to clients.

Beyond that, ON Semi does have about 35 percent revenue exposure to Japanese customers.

We expect that in the near-term, these customers will not be buying as much product from ON Semi and other suppliers, Berger said.

If Japan is $300 million in quarterly revenues, and the Japan tragedy struck with about 15 days remaining in the quarter, and demand from these customers falls by 40 percent over the next month, then the first quarter 2011 revenues could be impacted by $20 million, or about 2 percent of revenues.

For the second quarter of 2011, such an exercise suggests that ON Semi's revenues could be impacted by roughly $50 million to 70 million in revenues (depending on how fast customer purchasing returns), or roughly 5 to 8 percent of total revenues, a slight near-term negative.

However, the analyst said, this is a short term impact, some demand could push into later second quarter or third quarter as opposed to just evaporating away, and some products like discretes could see incremental supply tightness that could aid pricing and margins later this year.

Net, we like ONNN at current levels (though if the Japanese situation gets worse ONNN could revisit $8.50), and still think the firm can achieve $1.30 run rate earnings by year-end 2011, and suggesting ONNN shares are a bargain at current prices, said Berger who has an outperform rating on ON Semiconductor stock.

Shares of ON Semiconductor were up 5 cents to $9.84 on Nasdaq.