Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: Shares of energy-management chip maker ON Semiconductor (Nasdaq: ONNN) powered to gains as high as 12.6% in early trading today, all on many times the average trading volume.

So what: First-quarter sales beat analyst targets by 5% while earnings posted a 35% positive surprise. Second-quarter guidance also points significantly above analyst expectations and is based on solid information such as rising order backlogs and booking trends, rather than on pure guesstimation.

Now what: The Sanyo Semiconductor acquisition is already paying dividends, adding about $0.06 of non-GAAP earnings per share in the first quarter. Previous owner Panasonic (NYSE: PC) wanted Sanyo only for its rechargeable-battery know-how and was happy to hand the chip division off to ON. Fairchild Semiconductor (NYSE: FCS) and Maxim Integrated Products (Nasdaq: MXIM) had better look out, because it looks as though ON knows how to swing its shiny new weapon.

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