Sector Snap: Semiconductors rally

The Philadelphia Semiconductor Sector index jumped 10.76, or 2.8 percent, to 391.04.

Silicon Labs said Tuesday strong demand, especially in its voice and embedded modem businesses, will help boost its earnings, excluding stock options costs, to 40 cents and 42 per share. Its prior outlook was for adjusted earnings of 37 cents to 39 cents per share, and analysts polled by Thomson Financial predict a profit of 38 cents per share.

The company's shares rose $2.74, or 7.7 percent, to $38.58 in midday trading. In the past 52 weeks, the stock has traded between $25.39 and $45.15.

"We continue to believe SLAB remains one of the most interesting companies in our (coverage) universe with a combination of diversified high-margin, high-growth businesses," wrote Deutsche Bank analyst Arnab Chanda in a note to investors.

Shares of Marvell Technology Group Ltd., which makes chips for data storage and communications uses, also climbed.

Cowen and Co. analyst Daniel Berenbaum started coverage of the company with an "Outperform" rating Wednesday.

"With strong product offerings in growing markets and evidence accumulating that its operational and financial house is in order, we see an opportunity for MRVL to outgrow peers and generate significant growth and cash flow," he wrote in a note to investors.

Marvell's shares rose 72 cents, or 4.1 percent, to $18.10. The stock has traded between $9.77 and $20.04 in the past year.

Elsewhere, Advanced Micro Devices Inc. jumped 28 cents, or 4.5 percent, to $6.52, having changed hands between $5.31 and $16.19 in the past year.